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Title: Parasites - A Treatise on the Entozoa of Man and Animals, Including - Some Account of the Ectozoa
Author: Cobbold, T. Spencer
Language: English
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project.)



Transcriber’s notes:

The text contains numerous inconsistencies involving spelling,
hyphenation, punctuation, and other aspects. Some of the spelling
variations possibly represent authentic contemporary alternatives while
others may be attributable to the variety of languages occurring in the
book – English, Italian, German, Spanish, Danish, Swedish, Dutch, French,
Portuguese and possibly others.

Spelling inconsistencies that are clearly typos have been corrected
where appropriate but those representing alternative spellings have been
left unchanged. A list of corrections and common inconsistencies is
appended at the end of the book.

Punctuation anomalies have been corrected silently (e.g. missing
periods, commas and semicolons, incorrect or missing quotation marks,
unpaired parentheses), particularly in the extensive bibliographic
lists, in the index and in the Figure captions.

There is significant inconsistency between the headings displayed in the
Table of Contents (TOC) and those in the text, most noticeably in Book
II where the last four entries in the TOC are appropriately identified
as Sections II, III, IV, and V but the corresponding headings in the
text are incorrectly named as Section II Part I, Part II, Part III and
Part IV. TOC headings and text headings also vary in their specific
wording and the presence or absence of parentheses and dashes.

Inconsistent ways of expressing measurements are as in the original, for
example, one fifth of an inch, 1/5th of an inch, 1/5 of an inch, 1/5″ of
an inch, 1/5″.

The dimensions of many organisms are described using an archaic unit of
length: the ‘line’ which was equivalent to 1/12 of an inch. However, as
the inch itself varied, both within and between countries, it was a
non-standard measurement, e.g. in England one line was equivalent to
2.117 mm but the French (Paris) ligne was equal to 2.256 mm. The triple
prime symbol ‴ was used to represent the unit and occasionally appears
in this text (along with the more common ′ and ″ symbols representing
feet and inches). The ligne unit is still used by watchmakers.

The closing pages of the book contain advertising material about other
works from the same publisher. In some cases the date of publication
could not be determined with certainty because of the inferior quality
of the page scans.



                               PARASITES.



                               PARASITES;

                           A TREATISE ON THE

                      ENTOZOA OF MAN AND ANIMALS,

                               INCLUDING

                      SOME ACCOUNT OF THE ECTOZOA.

                                   BY
               T. SPENCER COBBOLD, M.D., F.R.S., F.L.S.,

       HONORARY VICE-PRESIDENT OF THE BIRMINGHAM NATURAL HISTORY
                       AND MICROSCOPICAL SOCIETY.

                             [Illustration]

                                LONDON:
               J. & A. CHURCHILL, NEW BURLINGTON STREET.
                                 1879.



                                PREFACE


My introductory treatise on the Entozoa having long been out of print,
it occurred to me that instead of attempting another edition it would be
better to write an entirely new work, employing only such fragmentary
portions of the old treatise as would harmonise with the far wider
design I have now in view. Whilst, therefore, I have freely utilised
a selection of the illustrations given in the elementary volume,
comparatively few of its pages have been incorporated in the present
work.

Dealing with parasites and parasitism after a manner not hitherto
attempted I have purposely omitted minute anatomical descriptions,
and, with rare exceptions, I have avoided the introduction of clinical
details. While bringing to a focus the records of, and principal
references to, a widely scattered, intricate, and voluminous literature,
it has been my chief endeavour to supply abundance of original matter
of a kind that cannot be found in the columns of any existing treatise.
Whether I have succeeded or not the experienced helminthologist alone
can judge. He, at all events, will perceive that the summary, though
compressed within the space of a moderate-sized octavo, can only have
resulted from sustained effort.

This treatise is not professional, that is to say, it does not concern
itself with therapeutics or the curative treatment of parasitic
affections; yet it introduces and helps to solve many questions
relating to epidemics, endemics, and epizoötics due to parasites. The
medical man who only looks at the phenomena of parasitism as displayed
within the human territory must of necessity acquire a cramped, narrow,
and distorted conception of the rôle played by parasites in the
production of disease. Let it be freely granted that to the practising
physician, as such, it matters little how many beasts, birds, reptiles,
or fishes perish annually from parasitic affections; yet, when it is
demonstrable that a large proportion of the strictly human entozoa
require a change of hosts--or, in other words, need to pass through the
bodies of the lower animals--then it is evident that some acquaintance
on his part with the entozoa infesting animals becomes a practical
necessity. Knowledge of the kind here offered will often materially
aid him in recommending prophylactic measures. Moreover, the study of
comparative pathology, almost ignored in England, conveys with it other
lessons of high value in relation to the healing art. The great mind
of John Hunter comprehended all this long ago, as any student of the
beautiful preparations contained in the museum of the Royal College
of Surgeons may readily convince himself; and this is all the more
noteworthy, since the subject concerns the physician rather than the
surgeon.

To the naturalist the second half of this book addresses itself in a
very direct manner. When engaged in his dissections, an appeal to its
pages will often enable him to decide at once as to the species of
parasite accidentally encountered, and if a full diagnosis be demanded
it will guide him to better sources of information. Many hundreds of
correspondents, not having ready access to the systematic writings of
Rudolphi, Diesing, and Dujardin, have requested me to identify their
“finds.” I have rarely or never failed to comply with their requests;
but it is hoped that the present work may prove of ready service to
subsequent inquirers, and thus place a reasonable limit upon the number
of future applicants. Since the manuscript of this work was completed I
have received Dr von Linstow’s _Compendium der Helminthologie_, which,
for the purposes held in view by the author, leaves little to be desired.

Expressly to meet the requirements of the Sanitarian I have dwelt upon
the developmental phenomena exhibited by those parasites that occasion
fatal helminthiases; and, in this relation, I have not confined my
remarks to the parasites that are injurious to man in a direct manner,
but have extended my observations to the genesis of those entozoa that
prove destructive to horses, to beasts of burden generally, and to other
creatures which, like cats and dogs, are in various ways subservient
to man’s wants. It will be seen that in this way several questions
relating to the purity of water and flesh-food, respectively, have been
incidentally brought under notice.

In view of the magnitude of the task which my enthusiasm, perhaps
unwarrantable, has led me to undertake, I know full well how
considerately my foreign friends and correspondents will deal with
the errors of omission and commission that they will certainly detect
in these pages. If there be any educated persons at home who still
affect to despise the revelations of helminthology, I can assure them
that their prejudices are misplaced. The study of the structure and
economy of a humble parasite brings to the investigator no slight
insight into the workings of nature. If these workings cannot at all
times be pronounced to be “good and beautiful,” they must at least
be characterised as “true.” The knowledge of the true--especially if
that knowledge by its practical applications be calculated to confer
substantial benefits upon man and his inferior fellow-creatures--ought
to be held in high esteem; but, apart from this purely utilitarian view,
there remains for the investigator the delight occasioned by the in-rush
of new scientific ideas. The average mind, being either essentially
commercial or ridiculously sentimental, as the case may be, is totally
incapable of comprehending the motive power that animates and guides the
votary of science. The late Professor Faraday, a man wholly untinged by
the ambitions of wealth and power, once remarked to me that there were
no people so difficult to instruct as those who were ignorant of their
own ignorance. It is just these very persons who, when placed in high
positions of social, political, or professional trust, most powerfully
contribute to check a nation’s progress. There are too few genuine
workers at science in this country. As one of the rank and file, I claim
only to have honestly contributed my mite. I should like to see a small
army of helminthologists rise up and lay siege to the fortresses at
present securely held by thousands of death-dealing parasites.

                                                         T. S. C.

  74, Portsdown Road, London
         _May, 1879_.



                         SYNOPSIS OF CONTENTS.


                                                                  PAGE

  GENERAL INTRODUCTION                                               1


                                BOOK I.

                           PARASITES OF MAN.

  SECTION I.--TREMATODA (FLUKES)                                    14
     "   II.--CESTODA (TAPEWORMS)                                   56
     "  III.--NEMATODA (ROUNDWORMS AND THREADWORMS)                149
     "   IV.--
          PART  I.--Acanthocephala (Thornheaded Worms)             256
           "   II.--Suctoria (Leeches)                             257
           "  III.--Arachnida (Parasitic forms of)                 259
           "   IV.--Crustacea (alleged Parasitic forms of)         268
           "    V.--Insecta (Parasitic forms of)                   269
           "   VI.--Protozoa (Parasitic forms of)                  276

  APPENDIX (Statistics)                                            284


                                BOOK II.

                         PARASITES OF ANIMALS.

  SECTION I.--PARASITES OF MAMMALIA.
          PART  I.--Parasites of Quadrumana                        289
           "   II.--Parasites of Cheiroptera                       293
           "  III.--Parasites of Insectivora                       295
           "   IV.--Parasites of Carnivora                         297
           "    V.--Parasites of Pinnipedia                        313
           "   VI.--Parasites of Rodentia                          315
           "  VII.--Parasites of Edentata                          320
           " VIII.--Parasites of Ruminantia                        322
           "   IX.--Parasites of Solidungula                       356
           "    X.--Parasites of Pachydermata                      393
           "   XI.--Parasites of Cetacea and Sirenia               416
           "  XII.--Parasites of Marsupialia and Monotremata       430
     "   II.--PARASITES OF AVES                                    434
     "  III.--PARASITES OF REPTILIA                                451
     "   IV.--PARASITES OF PISCES                                  457
     "    V.--PARASITES OF EVERTEBRATA                             480

  APPENDIX (Hæmatozoa)                                             485

  INDEX                                                            489



                        LIST OF BIBLIOGRAPHIES.


                                                                  PAGE

  No. 1. General and systematic treatises                            8

      2. Minor treatises, general memoirs, and monographs           10

      3. Literature of _Fasciola hepatica_ in man                   17

      4. _Distoma lanceolatum_ in man                               20

      5.     "   _crassum_                                          28

      6.     "   _sinense_                                          29

      7.     "   _conjunctum_ in man                                33

      8.     "   _heterophyes_                                      35

      9.     "   _ophthalmobium_                                    36

     10. _Tetrastoma_ and _Hexathyridium_                           36

     11. _Amphistoma hominis_                                       38

     12. _Bilharzia hæmatobia_                                      55

     13. _Tænia mediocanellata_ and the beef-measle                 84

     14.    "  _solium_ and the pork-measle                         94

     15.    "  _tenella_ and the mutton-measle                      99

     16.    "  _lophosoma_                                          99

     17.    "  _nana_                                              100

     18. Tapeworm varieties and monstrosities                      105

     19. _Bothriocephalus latus_, _B. cordatus_, and
            _B. cristatus_                                         112

     20_a._ General literature of hydatids (English)               141

       _b._ Hydatids of the liver                                  142

       _c._    "              "  and other organs together         143

       _d._ Liver hydatids. American cases                         144

       _e._ Hydatids of the lungs and pleura                       144

       _f._    "     of the kidney                                 144

       _g._    "     of the spleen, omentum, and abdominal cavity  144

       _h._    "     within the pelvic cavity                      145

       _i._    "     of the heart and blood-vessels                145

       _k._    "     of the brain and cranial cavity               145

       _l._    "     of the bones                                  145

       _m._    "     of the breast, muscles, and soft parts        146

       _n._    "     of uncertain seat                             146

       _o._    "     of animals                                    147

       _p._    "     in man. Foreign literature                    147

     21. _Trichina spiralis._ English literature                   174

              "               Foreign literature                   177

     22. _Trichocephalus dispar_                                   180

     23. _Filaria Bancrofti_ (_F. sanguinis hominis_)              202

         Supplement (Hæmatozoa)                                    488

     24. _Filaria loa_                                             206

     25.     "   _lentis_                                          206

     26.     "   _labialis_                                        207

     27.     "   _trachealis_ and _F. bronchialis_                 208

     28. _Eustrongylus_ (_Strongylus_) _gigas_                     210

     29. _Dochmius duodenalis_                                     216

     30. _Dracunculus medinensis_                                  224

     31. _Oxyuris vermicularis_                                    232

     32. _Leptodera_ (_Anguillula_) _stercoralis_ and
            _L. intestinalis_                                      235

     33. _Ascaris mystax_                                          241

     34.     "   _lumbricoides_                                    251

     35. _Echinorhynchus gigas_                                    257

     36. _Sanguisuga medicinalis_ and other leeches                259

     37. _Pentastoma tænioides_ and _P. constrictum_               265

     38. _Demodex_, _Sarcoptes_, and other Arachnidan ectozoa      268

     39. _Gammarus pulex_ in man                                   269

     40. Bugs, lice, and other insect parasites of man             275

     41. _Psorospermiæ_, _Gregarinæ_, and other protozoa           283

     42. _Entozoa_ of monkeys                                      293

     43.     "     and ectozoa of bats                             295

     44.     "     of insectivorous mammals                        297

     45.     "     of carnivorous mammals                          310

     46.     "     of seals                                        315

     47.     "     of rodents                                      320

     48.     "     of sloths and ant-eaters                        322

     49.     "     of ruminants                                    352

     50.     "     and ectozoa of solipeds                         389

     51.     "            "    of elephants                        400

     52.     "     of rhinoceroses                                 402

     53.     "     of the hippopotamus and tapir                   403

     54.     "     and ectozoa of swine                            414

     55.     "     of whales, dolphins, and dugongs                429

     56.     "     of marsupial animals                            434

     57.     "     and ectozoa of birds                            448

     58.     "     of reptiles                                     456

     59.     "     and ectozoa of fishes                           477

     60.     "     of insects, crustaceans, and mollusks           484



                                ERRATUM.


Page 296, line 24 from the top, for “in the glow-worm (_Glomeris_),”
read “in a myriapod (_Glomeris_) which is phosphorescent like the
glow-worm.”



                               PARASITES.

                             INTRODUCTION.


No person can derive advantage from the study of parasites unless the
subject be approached in a right frame of mind. In other words, the
student of helminthology must, as a primary discipline, dispossess
himself of all preconceived opinions whatsoever, and in an attitude of
child-like simplicity seek truth for its own sake. Unless the mind be
absolutely free and unfettered it cannot rightly interpret the facts of
this peculiar department of biological science. Those students who are
nervously anxious to reconcile the conclusions of modern science with
the ideas of their forefathers are certain to remain just as ignorant of
the true value and significance of nature-teachings as all their fathers
were.

Whether dealing with the external or internal forms, the study of
parasites of man and animals is practically one of boundless extent;
and there is probably no department of knowledge, possessing an equal
value in relation to the welfare of man and beast, that is so thoroughly
misunderstood by those who are directly concerned in the appreciation of
its revelations. This has arisen from a total misconception as to cause
and effect. Most people, not excluding even the votaries of the healing
art, following tradition, regard the internal parasites or entozoa as
creatures either directly resulting from certain diseased conditions
of their _hosts_ or as organisms which would not have existed if their
_bearers_ had been perfectly healthy. Nothing can be more absurd. Such a
conclusion is utterly at variance with all logical deduction from known
facts. It is, however, quite on a par with multitudes of other popular
delusions which, in spite of the advance of science, will probably never
become wholly eradicated from the public mind. People who hold these
notions either cannot or do not desire to reject a view which has for
them a dominating power almost equal to that of any known religious
dogma. In conversation I have repeatedly noticed this to be the case.
These people are the victims of educated ignorance and they will never
allow that parasites are natural developments, accomplishing ends or
parts of the orderly mystery which reigns everywhere. Some of then
still cling to the creed that the presence of parasites, of internal
ones at least, betokens evidence of Divine disfavor; and their minds
are troubled with all sorts of distressing and childish conceptions.
In the present age one would have thought that such ridiculous ideas
could not be seriously maintained; but instead of being relegated to
the limbo of similar “old wives’ fables” they dominate the opinions of
thousands of our so-called educated people. The genuine searcher after
truth does not need to be told that all preconceptions of this order
hopelessly obscure the mental vision. They operate to render a just and
adequate understanding of the science of helminthology impossible. The
biologist may say what he lists, but he knows perfectly well that the
superstitious mind will continue to ignore the precious and elevating
results of scientific research, and that it will perseveringly continue
to persuade itself that internal worms, parasites, and entozoa, of
whatever kind, belong to the category of “plagues” liable to be
distributed as special punishments for human wrong-doing.

As remarked in my previous treatise, the best way of studying the
entozoa is to regard them as collectively forming a peculiar _fauna_,
destined to occupy an equally peculiar territory. That territory is the
wide-spread domain of the interior of the bodies of man and animals.
Each bearer or “host” may be viewed as a continent, and each part or
viscus of his body may be regarded as a district. Each district has its
special attractions for particular parasitic forms; yet, at the same
time, neither the district nor the continent are suitable as permanent
resting-places for the invader. None of the internal parasites “continue
in one stay;” all have a tendency to roam; migration is the soul of
their prosperity; change of residence the essential of their existence;
whilst a blockade in the interior soon terminates in degeneration and
death. I repeat it. The entozoa constitute a specialised fauna. What
our native country is to ourselves, the bodies of animals are to them.
To attack, to invade, to infest, is their legitimate prerogative. Their
organisation, habits, and economy are expressly fashioned to this
end. How remarkable and complex is their structure, and how peculiar,
diverse, and varied are their ways and wanderings, the contents of this
volume will, I trust, sufficiently explain. The puerile horror which
even some scientific persons affect to display in regard to the subject
is altogether out of place. To the rightly balanced mind the study of
these much abused “worms” is just as attractive as any other section
of zoology. Helminthology opens up to our view many of the strangest
biological phenomena of which the human mind can take cognisance; whilst
a profound and extended knowledge of the subject, in all its bearings,
is calculated to secure to the community a rich practical reward by
enabling us to do effectual battle with not a few of the many ills of
life to which our flesh is heir.

Further on the general advantages to be derived from the study of
parasites I cannot here dilate, and it becomes the less necessary
that I should do so, since I have entered upon the subject very fully
elsewhere. The character of the present work, moreover, imposes
brevity. If the plan which I now propose to follow should not be deemed
altogether satisfactory from the purely zoological standpoint, it
will nevertheless have the advantage of simplicity and novelty; and
knowing full well the difficulties that must surround any attempt to
give a perfect classification of the entozoa, considered as a natural
group, I feel sure that my helminthological friends will credit me with
exercising a wise discretion in selecting the simplest available method
of arrangement. My plan, therefore, is to devote separate sections of
this work to the parasites of the different classes of vertebrated
animals, including man, treating of the various species in regular
succession. This arrangement is merely one of convenience and has no
reference whatever to conceptions of zoological equivalency as variously
interpreted and maintained by authors and investigators. The parasitic
groups will be taken up in the following order, quite irrespective of
their relative importance, and also without any attempt to treat each
group with equal fulness. In the matter of recent literature only will
the present record and summary make any approach toward completeness, my
hope being to render this treatise indispensable and trustworthy as a
ready means of reference.

I. FLUKES. TREMATODA.--This group embraces several families of
parenchymatous worms. The various species exhibit one or more
suckers, which the older naturalists regarded as so many mouths or
_perforations_. Hence the ordinal title. The term fluke is of Saxon
origin, meaning anything flat. Thus, it has been applied to sole-fish
or flounders, to the flattened halves of the tail of cetaceans, to the
blades of anchors, and so forth. Although the common liver fluke is
flat, many species of the order are round, biconvex, or even filiform
organisms. I recognise six families:--_Monostomidæ_, _Distomidæ_,
_Amphistomidæ_, _Tristomidæ_, _Polystomidæ_, and _Gyrodactylidæ_. Most
of the species are entozoal; but many adhere to the surface of the body
of piscine hosts.

II. TAPEWORMS. CESTODA.--This comprises not only the tapeworms, but
also the measles and other bladder-worms or cystic Entozoa of the old
authors (Cystica). The Greek word _kestos_ means a band or girdle;
hence the ordinal term above given. The bladder-worms, including
Hydatids, Cysticerci, &c., are the larval stages of growth of various
tapeworms. The further reduction of this order into sub-orders or
families requires careful attention. At present we have _Tæniadæ_,
_Acanthotæniadæ_, _Dibothridæ (= Bothriocephalidæ)_, _Diphyllobothridæ_,
_Tetrarhynchidæ_, and _Tetraphyllobothridæ_. All the genera and species
are entozoal. The proposal to separate the snouted or proboscidiform
tapeworms (_Rhynchotæniadæ_) from those in which the rostellum is absent
(_Arhynchotæniadæ_) does not recommend itself to my judgment.

III. ROUNDWORMS. NEMATODA.--This series comprises not only lumbricoid
or roundworms proper, but also threadworms. The term derives its origin
from the Greek word _nema_, signifying a thread. It likewise includes
the strongyles, the term _strongulos_ meaning round or cylindrical.
This is a very extensive group whose parasitic members are strictly
entozoal, whilst the non-parasitic forms are either entirely free or
they infest plants. Some of the so-called free nematoids live in the
slime of animals. The artificial classification by Schneider, based
on the muscular system, places these parasites in three well-marked
groups, but I think it a disadvantage to separate widely many really
closely allied forms. Thus, in his _Polymyarii_ we have the genus
Enstrongylus, and in his _Meromyarii_ the Strongyli proper. Most of the
genera may be fairly included in the following families:--_Ascaridæ_,
_Cheiracanthidæ_, _Cucullanidæ_, _Strongylidæ_, _Trichinidæ_,
_Oxyuridæ_, _Trichocephalidæ_, _Filaridæ_, _Gordiidæ_, _Anguillulidæ_.

IV. THORNHEADED-WORMS. ACANTHOCEPHALA.--This group embraces a small
series of parasites, which, in general appearance, resemble the nematode
worms. They differ, however, essentially, being, as the term indicates,
furnished with spine-covered heads. They are, moreover, destitute
of digestive organs. The species are entozoal in habit, abounding
particularly in fishes and reptiles. At present, all the known forms are
included in one family (_Echinorhynchidæ_), which also comprises only a
single genus.

V. ANNELID PARASITES. SUCTORIA.--In this category one must place all
such suctorial annelids as affix themselves to hosts for a longer or
shorter period. Many of the leech-like parasites (_Clepsinidæ_, and
especially _Malacobdellidæ_) remind one of certain flukes (_Tristoma_,
&c.) possessing ectozoal habits; whilst the leeches, properly so called,
afford instances of the passage from a semi-parasitic to what has been
called the free parasitic mode of existence. In tropical countries these
creatures very readily attach themselves to man and animals, often
creating severe distress. The genera _Clepsine_ and _Hæmocharis_ attack
mollusks and fishes respectively. The species are all ectoparasitic and
exceedingly numerous. They cannot be described in this work.

VI. ARACHNID PARASITES, ARACHNIDA (part of).--The great class of
articulated, limb-jointed, or, more strictly, arthropodous animals,
includes a variety of parasites. The mites, true ticks, and such like
creatures, belong to this group. Some few of them are entozoal in
habit, others are only partially so, whilst the majority are entirely
ectozoal. Of the two great sections of Arachnida, namely, Pulmonaria
and Trachearia, the latter alone contains strictly parasitic forms. The
parasitic species belong to the following families:--_Pentastomidæ_,
_Pycnogonidæ_, _Ixodidæ_, _Acaridæ_, _Gamasidæ_, _Hydrachnidæ_,
_Solpugidæ_. The parasitism of some of the species is very partial or
slight. Thus, certain of the water mites, in their juvenile state,
dwell on aquatic insects only; and the tick-like _Gamasidæ_ occur upon
dung-beetles. The other ectozoal species attack vertebrated animals, and
several attach themselves to man himself. The whale lice (_Cyamidæ_) are
here included in the _Pycnogonidæ_, though often placed by zoologists
with the Crustaceans.

VII. CRUSTACEAN PARASITES. CRUSTACEA (part of).--A large number of
species belonging to various well-marked sections of this great class
of Invertebrates are parasitic in their habits, most of them being
comprised in the so-called haustellated group. They are familiarly
known to zoologists as Epizoa. As this latter term implies, they are
strictly ectozoal in character, most of the species victimising fishes
by attaching themselves, not only to the general surface of the body,
but also to the eyes, and especially to the gills or branchiæ. The
species for the most part belong to the families _Lernæidæ_, _Caligidæ_,
_Dichelestidæ_, and _Argulidæ_. In this category must likewise be placed
two other families belonging to the so-called isopodous section of
edriophthalmatous crustaceans. These are the _Cymothoidæ_, which attach
themselves to the tails of fishes, and the _Bopyridæ_, which occupy
the branchial cavity of shrimps. The nature of this work precludes any
detailed notice of the numerous members of this section.

VIII. INSECT PARASITES. INSECTA (part of).--The insects, properly so
called (that is to say, arthropodous, evertebrated creatures, with six
legs), are many of them essentially parasitic in their habits. The most
important of these are “bots” and other larvæ or maggots of various
flies (Diptera). The varieties of lice are also included in this group.
Some few of the insect parasites are strictly entozoal in habit, at
least for a part of their lifetime, being previously attached externally
for a short period only. Most of the forms are essentially ectozoal. A
very large number of insect tormentors, although deriving nourishment
from their victims, attach themselves to the animals for so short a time
that they cannot be classed as parasites under the ordinary acceptation
of the term. As examples of the so-called free parasitism, the autumnal
flies (_Tabanidæ_) and _Stomoxys_ may be cited. Although embracing
but few strictly parasitic forms we have the following:--_Œstridæ_,
_Hippoboscidæ_ (with _Melophagus_), and _Nycteribiidæ_. In regard to the
maggots of _Muscidæ_ and _Sarcophagæ_, some of them are parasitic on
animals and man, whilst others are parasitic upon insects themselves.
The larvæ of _Conopidæ_ attack humble-bees internally. Those parasitic
insects, properly so called, which, like certain of the crustaceans,
are sometimes spoken of as epizoa, comprise three well-marked families.
Thus, we have Pediculidæ (the source of lousiness), _Philopteridæ_, and
_Liotheidæ_. Both of the latter embrace numerous species which for the
most part content themselves with devouring the feathers of birds and
the hairs of quadrupeds. In addition to these it may be added that some
of the rat-tailed larvæ or Helophilus maggots (_Syrphidæ_) are parasitic
in man and quadrupeds, as are also the larvæ of the churchyard beetle
(_Blaptidæ_). The closely allied _Tenebrionidæ_ and other coleopterous
families also supply various maggots possessed of parasitic habits.
Fleas and bugs come under Van Beneden’s category of free parasites. This
is equivalent to calling them non-parasitic parasites, an expression
which looks very like a contradiction of terms.

IX. PROTOZOAL PARASITES. PROTOZOA (part of.)--This miscellaneous
assemblage of minute creatures embraces a number of parasites of very
low organisation. In the present work it is neither desirable nor
necessary to hazard any statements respecting their precise zoological
position. It is sufficient to say that the parasitic protozoa are
for the most part entozoal in habit, not a few of them possessing
vegetable affinities. The microscopic _Bacteridæ_, _Gregarinidæ_, and
_Psorospermiæ_, comprise a multitude of organisms which are strictly
parasitic in their habits, whilst amongst the _Infusoria_ we find
numerous forms which, though dwelling in the intestinal canal of their
hosts, do not derive nourishment in a direct manner from their bearers.
Of this kind are _Paramecium_ and _Balantidium_. The separation of the
psorospermiæ and gregarinæ into genera is attended with difficulty;
nevertheless, I have for convenience long recognised various types
under titles corresponding with the names of the observers who first
discovered them (_Hesslingia_, _Gubleria_, _Lindermannia_, and so
forth). Of necessity, the protozoal parasites will only be incidentally
noticed in this work. In this category I place the falsely so called
“cattle-plague bodies.” The micrococci and bacteria hardly come within
the province of the helminthologist.

Without prejudice to the foregoing restrictions I must at the same time
observe that the varied characters presented by the above-mentioned
groups show how impossible it is to treat the subject of parasitism
adequately, if one is obliged to confine his remarks to the internal
parasites or helminths proper. Many creatures possessed of entozoal and
ectozoal habits are parasites in every legitimate sense of the term, and
yet they do not belong to the class _Helmintha_ in its common zoological
acceptation. _That_ class taken by itself may still be allowed to stand
pretty much as I represented it in 1864; but in the present work I
cease to speak of the Entozoa as in any sense the zoological equivalent
of the _Helmintha_. I prefer to employ the term Entozoa in its popular
and wider acceptation. It conveniently stands thus, moreover, in direct
contradiction to the term Ectozoa.

As this work treats of parasites only, I purposely refrain from dealing
with the Turbellarians, and certain other creatures usually classed with
_Vermes_. The vague term “worms,” so often employed as the equivalent
of _Helmintha_, is misleading in many ways. I should like to see it
adopted only when speaking of the Annelids proper. It would still have
a sufficiently wide application, seeing that it would include Leeches,
Earth-worms, Naids, Tubed-worms, Sea-lobworms, Sea-mice, Nereids, and a
host of other setigerous species. Notwithstanding the remote connection
subsisting between “intestinal worms” and worms properly so called,
the notion that an intimate relation subsists between the lumbricoid
helminths and earth-worms will probably never entirely disappear from
the popular or even from the professional mind.

Since one of the principal features of this treatise is to afford
a handy means of reference to the rich and extended literature of
parasitism, I here subjoin a list of general and systematic treatises.
To most of these I shall constantly refer. Full special references to
detached memoirs will appear in the bibliographies scattered throughout
the body of the work.

BIBLIOGRAPHY (No. 1).--_Bremser_, ‘Ueber lebende Würmer im lebenden
Menschen,’ Vienna, 1819; French edit., by Grundler, 1824.--_Idem_,
‘Icones helminthium,’ Vienna, 1824.--_Cobbold, T. S._, ‘Entozoa,
an Introduction to the Study of Helminthology, with reference
more particularly to the Parasites of Man,’ London, 1864; Supp.,
1869.--Reviews in the ‘Lancet,’ Sept. 24th, 1864, p. 353; in the
‘Med. Times and Gaz.,’ Oct. 29th, 1864, p. 474; in the ‘Athenæum,’
Oct. 15th, 1864, p. 493; in ‘Cosmos,’ Oct. 27th, 1864, p. 463; in the
‘Reader,’ Nov. 26th, 1864, p. 668; in the ‘Edinburgh Vet. Review,’
Nov., 1864, p. 662; in ‘Intellectual Observer,’ vol. vi, 1864, p. 190;
in the ‘Quarterly Journal of Science,’ No. v, January, 1865, p. 145;
in the ‘Quart. Journ. of Micr. Science,’ New Series, No. 17, Jan.,
1865, p. 43; in ‘Popular Science Review,’ Jan., 1865, p. 214; in the
‘Veterinarian,’ Feb., 1865, p. 97; in the ‘Medical Mirror,’ Jan.,
1865, p. 23; in the ‘Natural History Review’ for July, 1865; in the
‘British and Foreign Medico-Chirurgical Review,’ April, 1865, in the
‘Edinburgh Medical Journal’ for April, p. 929; in the ‘Social Science
Review’ for Feb. 1, 1866, p. 169; in ‘Dublin Quart. Journ. of Medical
Science’ for Aug., 1867.--_Davaine, C._, ‘Traité des Entozoaires et des
maladies vermineuses de l’homme et des animaux domestiques,’ Paris,
1860, 2nd edit., 1877-79.--_Diesing, C. M._, ‘Systema helminthum,’
Vienna, 1850.--_Dujardin, F._, ‘Histoire naturelle des helminthes
ou vers intestineaux,’ Paris, 1845.--_Goeze, T. A. S._, ‘Versuch
einer Naturgeschichte der Eingeweidewürmer thierischer Körper,’
Blankenburgh, 1782.--_Küchenmeister, F._, ‘Die in und an dem Körper des
lebenden Menschen vorkommenden Parasiten,’ Leipsic, 1855, 2nd. edit.,
1878-79; Eng. edit., by Lankester, 1857.--_Le Clerc, D._, ‘A Natural
and medicinal History of Worms bred in the bodies of men and other
animals’ (_sic_), Browne’s edit., London, 1721.--_Leuckart, R._, ‘Die
menschlichen Parasiten, und die von ihren herruhrenden Krankheiten,’
Leipsic und Heidelberg, 1863-1876.--_Redi, F._, ‘De animalculis vivis
quæ in corporibus animalium vivorum reperiuntur, observationes;’ Coste’s
edition, Amstelædami, 1688.--_Rudolphi, C. A._, ‘Entozoorum sive vermium
intestinalium historia naturalis,’ Amsterdam, 1808.--_Idem_, ‘Entozoorum
Synopsis,’ Berlin, 1819.--_Van Beneden, P. J._, ‘Animal Parasites and
Messmates,’ London, 1876.

Several of the above works, while professing to deal with human
parasites only, cover more or less of the whole ground of helminthology.
Leuckart’s work is invaluable in this respect; and in the matter of
literary references of a professional kind Davaine’s treatise is itself
well nigh exhaustive. In any ordinary volume it is not possible to
give a complete bibliography of parasitism. I make no pretension to
do so here; nevertheless, the large number of modern memoirs that I
have received from the distinguished writers themselves, enables me to
render this part of my book very useful. As second only in importance
to the above-mentioned works may be added the following--whether minor
treatises, memoirs, monographs, comprehensive articles, or reports of a
general or special character, respectively. As such it will be seen that
some of them are sufficiently comprehensive, and their mere enumeration
will enable the beginner to realise something like a fair estimate of
the scope of helminthology. In the case of my own works I have ventured
to add references to reviews and notices, because many of the latter
contain valuable original suggestions made by the various anonymous
writers.

BIBLIOGRAPHY (No. 2).--_Bastian, H. C._, “On the Anatomy and Physiology
of the Nematoids, parasitic and free,” ‘Philosophical Transactions,’
1865 (see also Bibliog., No. 60).--_Cobbold, T. S._, ‘Worms; a series of
lectures on Practical Helminthology,’ London, 1872; Italian edition by
Tommasi. Milan, Florence, &c., 1873.--_Idem_, ‘The Internal Parasites
of our Domesticated Animals,’ London, 1873; Italian edit. by Tommasi,
Florence, 1874.--_Idem_, ‘Tapeworms (Human), their Sources, Varieties,
and Treatment,’ London, 3rd edit., 1875. Reviews (1st and 2nd edit.,
with ‘Threadworms’), in ‘Brit. and For. Med.-Chir. Review’ for 1867,
p. 433; in ‘Edin. Med. Journ.’ for 1866-67, p. 107; in ‘Lancet,’
Nov. 10th, 1866; in ‘Popular Science Review,’ Oct. 1st, 1866; in
‘Intellectual Observer,’ Oct. 1866; in ‘Med. Press and Circular,’
Jan. 16th, 1867; again in the ‘Lancet,’ for March 13th, 1867; and in
‘Dublin Quart. Journ. of Medical Science’ for 1867, 3rd edit.; in the
‘Field,’ Sept. 25th, 1875; and in ‘Popular Science Review’ for Jan.,
1876.--_Idem_, ‘Catalogue of the Specimens of Entozoa in the Museum
of the Royal College of Surgeons of England,’ London, 1866; noticed
in the ‘Lancet’ for March 24th, 1866, p. 321.--_Idem_, “On the best
Methods of displaying Entozoa in Museums,” ‘Journ. Linn. Soc.,’ vol.
viii, p. 170.--_Idem_, ‘New Entozootic Malady,’ &c., 1864; popular
brochure, reviewed in the ‘Lancet,’ Feb. 4th, 1865, p. 128; in the
‘Athenæum,’ Jan. 21st, 1865, p. 87; in the ‘British Med. Journal,’
Jan., 1865; in the ‘Veterinary Review and Stockowners’ Journal,’ No.
2, New Series, Feb., 1865, p. 76; in the ‘Reader,’ Feb. 4th, 1865, p.
142; in ‘Med. Times and Gaz.’ for June 2nd, 1865; in the ‘Field’ for
March 18th, 1865.--_Idem_, “Parasites of Man,” forming a series of
articles contributed to the ‘Midland Naturalist,’ 1878-79.--_Idem_,
“Notes on Entozoa contained in the various Metropolitan Museums,” in
‘Lancet,’ May 13th, 1865, p. 503.--_Idem_, “Report on _Plica polonica_,
in reference to Parasites,” in ‘Pathological Soc. Trans.,’ 1866, p.
419.--_Idem_, “Report on Experiments respecting the Development and
Migrations of the Entozoa,” ‘British Assoc. Reports’ (Bath Meeting)
for 1864, p. 111; and briefly noticed in ‘Lancet’ for Sept. 24th,
1864.--_Idem_, Miscellaneous observations, including “Note on Parasites
in the Lower Animals,” in ‘Dub. Med. Press’ for Feb. 11th, 1863, p.
154.--_Idem_, “Vegetables, Fruits, and Water considered as sources of
Intestinal Worms;” in the ‘Popular Science Review’ for Jan., 1865, p.
163.--_Idem_ (anonymously), “On Comparative Pathology and Therapeutics”
(in relation to Entozoötics); leading art. in ‘Lancet’ for Dec. 9th,
1865, p. 652.--_Idem_, “List of Entozoa, including Pentastomes, from
animals dying at the Zoological Society’s Menagerie, between 1857-60
inclusive, with descriptions of several new species,” ‘Proc. Zool.
Soc.,’ 1861.--_Idem_, “Remarks on all the Human Entozoa,” ‘Proc. Zool.
Soc.,’ 1862; abstracts in ‘Brit. Med. Journ.’ for 1862, and in ‘Edinb.
New Phil. Journ.,’ vol. xvii, new series, 1863, p. 145; in Report of
the ‘Proceed. of the Brit. Assoc. at Cambridge,’ 1862.--_Idem_, “Our
Food-producing Ruminants, and the Parasites which reside in them;
being the Cantor Lectures of the Society for the Encouragement of
Arts, Manufactures, and Commerce,” delivered in 1871, and pub. in the
‘Journal of the Soc. of Arts’ for that year.--_Davaine, C._, “Les
Cestoïdes,” in ‘Dict. Encycl. des Sci. Med.,’ Paris, 1876.--_Eberth,
C. J._, ‘Untersuchungen ueber Nematoden,’ Leipsic, 1863.--_Heller,
A._, “Darmschmarotzer,” in Von Ziemssen’s ‘Handbuch,’ Bd. vii, 1876;
and in the American edition of the same, 1877.--_Jones, T. R._, “List
of Entozoa of Greenland,” taken from _Krabbe_; ‘Arctic Manual,’ 1875,
p. 179.--_Krabbe, H._, ‘Helminthologiske Undersogelser,’ Copenhagen,
1865.--_Leuckart, R._, ‘Die Blasenbandwürmer und ihre Entwicklung,’
Giessen, 1856.--_Moquin-Tandon, A._, “Epizoa and Entozoa,” in Hulme’s
edit. of his ‘Elements of Medical Zoology,’ London, 1871.--_Nordmann,
A. von_, ‘Mikrographische Beiträge zur Naturgeschichte der wirbellosen
Thiere,’ Berlin, 1832.--_Olsson, P._, “Entozoa, iakttagna hos
Skandanaviska hafsfiskar.,” Lund, ‘Univ. Årsskrift,’ 1867.--_Owen,
R._, “Entozoa,” art. in Todd’s ‘Cyclopædia of Anat. and Physiol.,’
London, 1839.--_Idem_, “Entozoa,” ‘Lectures (iv and v) on the
Comp. Anat. and Physiol. of the Invertebrate Animals,’ London,
1855.--_Pagenstecher, H. A._, ‘Trematodenlarven und Trematoden,’
Heidelberg, 1857.--_Rhind, W._, ‘A Treatise on the Nature and Cure of
Intestinal Worms, &c.,’ London, 1829.--_Rolleston, G._, “Characteristics
of Nematelminthes and Platyelminthes,” in his ‘Forms of Animal
Life,’ Oxford, 1870.--_Schneider, A._, ‘Monographie der Nematoden,’
Berlin, 1866.--_Siebold, C. von._, “Parasiten,” art. in Wagener’s
‘Handwörterbuch der Physiol., &c.,’ 1845.--_Idem_, “Helminthes,” Book
v, in Burnett’s edit. of Siebold and Stannius’ ‘Comparative Anatomy,’
London and Boston, 1854.--_Thomson, A._, “Entozoa,” in the art. “Ovum,”
in Todd’s ‘Cyclop. of Anat. and Physiol.,’ London, 1859.--_Van Beneden,
P. J._, ‘Mémoire sur les Vers Intestineaux,’ Paris, 1858.--_Idem_, “Les
Vers Cestoïdes,” ‘Mém. de l’Acad. Roy.,’ Brussels, 1850.--_Verrill,
A. E._, “The External and Internal Parasites of Man and the Domestic
Animals,” ‘Rep. of Board of Agriculture,’ Connecticut, U.S., 1870.--_Von
Baer, K. E._, ‘Observations on Entozoa;’ in an analytical notice of
his article “Beiträge zur Kentniss der niedern Thiere,” from ‘Nova
Acta Nat. Cur.,’ tom. xiii, in the ‘Zool. Journ.,’ vol. iv, p. 250,
1828-29.--_Wagener, G. R._, ‘Beiträge zur Entwicklungsgeschichte der
Eingeweidewürmer,’ Haarlem, 1857.--_Weinland, D. F._, ‘An Essay on the
Tapeworms of Man,’ Cambridge, U.S., 1858.



                                BOOK I.

                           PARASITES OF MAN.


Whatever notions people may entertain respecting the dignity of the
human race, there is no gainsaying the fact that we share with the lower
animals the rather humiliating privilege and prerogative of entertaining
a great variety of parasites. These are for the most part entozoal in
habit. As the parasites are apt to cause suffering to the bearer, a
superstitious age sought to interpret their presence as having some
connection with human wrong-doing. We can now afford to smile at such
erroneous ideas. The intimate relation subsisting between parasitic
forms dwelling in man and animals, and their interdependence upon one
another, alone suffices to preclude the idea that parasites have been
arbitrarily placed within the human bearer. It would seem, indeed, that
our existence is essential to the welfare and propagation of certain
species of parasites. Possibly it is only by accepting the hypothesis
of “Natural Selection” that we can escape the somewhat undignified
conclusion that the entozoa were expressly created to dwell in us, and
also that we were in part designed and destined to entertain them. View
the matter as we may, the internal parasites of man and animals strictly
conform to a few well-known types of structure, but these types branch
out into infinitely varied specific forms. The vulgar mind sees nothing
attractive in the morphology and organisation of a parasitic worm, and
common-place conceptions of the beautiful cannot be expected to embrace
within their narrow grasp the marvelous harmony and order that pervade
the structure and economy of the individual members of this remarkable
class of beings.



SECTION I.--TREMATODA (Flukes).


_Fasciola hepatica_, Linneus.--The first form I have to consider is
the common liver fluke. The part this entozoon plays in the production
of disease will be fully stated when treating of the parasites of the
sheep and other ruminants. About twenty instances of its occurrence
in the human body have been recorded. It has been found beneath the
skin in the sole of the foot (Giesker), and also under the scalp
(Harris), and behind the ear (Fox). Its more frequent seat is in the
liver and gall-ducts (Pallas, Brera, Bidloo, Malpighi) and gall-bladder
(Partridge). The alleged cases by Bauhin, Wepfer, and Chabert are
spurious, as is probably also that given by Mehlis. Duval’s case appears
to be genuine, but the occurrence of the worm in the portal vein was
accidental. Dr Murchison has recorded a case, occurring at St Thomas’s
Hospital, where a solitary specimen was found in the liver. Dr H. V.
Carter also met with the worm in a young Hindoo.

In the second half of the present work I shall reproduce Blanchard’s
admirable figure of the sexually mature worm (Fig. 61), accompanied
by a categorical statement respecting the known facts of development.
In this place, however, I may observe that the cases recorded by
Giesker, Harris, and Fox had clearly pointed to the circumstance that
the higher larvæ of this fluke must be armed cercariæ, otherwise they
could not have bored their way through the human skin. As we shall
see, Dr Willemoes-Suhm’s investigations have furnished evidence as to
the truth of this supposition. For anatomical details I refer to my
introductory treatise. In the adult state the liver fluke has been known
from the earliest times. We have clear evidences that it was described
by Gabucinus in the year 1547, and also subsequently by Cornelius Gemma,
who, in a work published some thirty years later, refers to an epizootic
disease prevalent in Holland during the year 1552, and which was very
justly attributed to the parasite in question. After this date many
writers described the liver fluke more or less accurately, and entire
volumes were devoted to the consideration of the formidable disease
which it occasions. The nomenclature of the parasite has been a subject
of controversy. Amongst naturalists in general the common liver fluke
is often described under the combined generic and specific name of
_Distoma hepaticum_; but the title is both incorrect and inappropriate.
The proper generic appellation of this parasite is _Fasciola_, as
first proposed by the illustrious Linneus (1767) and subsequently
adopted by F. Müller (1787), Brera (1811), Ramdohr (1814), and others.
Unfortunately Retzius (1786) and Zeder (1800) changed the generic
title without good cause, and the majority of writers, following their
authority, refused to employ the original name, although a consideration
of the distinctive types of structure severally displayed by the genera
_Distoma_ and _Fasciola_ fairly demanded the retention of the Linnean
title. In later times M. Blanchard (1847) strongly advocated the
original nomenclature, and I have myself continually urged its adoption.
On somewhat different grounds Professor Moquin-Tandon followed the same
course.

In the sexually mature state the liver fluke commonly measures three
fourths of an inch in length, occasionally reaching an entire inch or
even sixteen lines; its greatest breadth also varying from half an
inch to seven or eight lines transversely; body very flat, presenting
distinct dorsal and ventral surfaces, frequently curled toward the
latter during life; upper or anterior end suddenly constricted, produced
and pointed in the centre, forming the so-called head and neck;
posterior extremity less acuminated, sometimes rounded, or even slightly
truncated; margins smooth, occasionally a little undulated, especially
towards the upper part; oral sucker terminal, oval, rather smaller than
the ventral acetabulum, which is placed immediately below the root of
the neck; reproductive orifices in the middle line, a little below the
oral sucker; intromittent organ usually protruded and spirally curved;
a central, light-coloured space, covering two thirds of the body from
above downwards, marks the region of the internal male reproductive
organs, being bordered on either side and below by a continuous dark
band, indicating the position of the so-called yolk-forming organs; a
small, brown-coloured, rosette-like body situated directly below the
ventral acetabulum, marks the limits of the uterine duct; a series of
dark lines, branching downwards and outwards on either side, indicate
the position of the digestive organs; general color of the body pale
brownish yellow, with a slight rose tint. The surface of the body,
though smooth to the naked eye, is clothed throughout with small
epidermal spines which diminish in size towards the tail.

If any argument were necessary to show how desirable it is to
furnish full descriptions of the commoner kinds of parasite, I could
adduce numerous instances that have been brought under my notice
where professional men and others have been entirely mistaken as to
the essential nature of their parasitic finds. Thus, I have known an
instance where a great authority on the diseases of dogs has persisted
in asserting for the free proglottides of a tapeworm a nematode origin;
and, in like manner, human tapeworm-segments have frequently been
mistaken for independent fluke parasites. One of the most remarkable
instances of this kind is that which I have elsewhere described as
an error on the part of Dr Chabert. My reasons for so regarding his
interpretation of the facts observed by him stand as follows:

In the ‘Boston Medical and Surgical Journal’ for the years 1852-53-54,
Dr J. X. Chabert described several cases of Tænia, and he averred that
the tapeworms were associated with numerous specimens of _Distoma
hepaticum_. The passage of distomes by patients during life was even
regarded by Dr Chabert as indicative of the presence of Tænia within
the intestines. Surely, I remarked, Dr Chabert was mistaken. Are not
these so-called distomes the well-known _proglottides_? Not willingly
doubting Dr Chabert’s statements, but desirous, if possible, of
verifying the accuracy of his conclusions, I wrote to him (March 22nd,
1864) requesting the loan of a specimen, but I was not fortunate enough
to receive a reply. In the “Case of Tænia” in a boy four and a half
years old, given in the 49th vol. of the journal, Dr Chabert writes as
follows:--“In consequence of his passing the _Distoma hepaticum_, I
concluded he must be afflicted with Tænia.” Further on it is added, that
the administration of an astringent injection “caused the discharge of
innumerable small worms (_Distoma hepaticum_).” I think this is quite
decisive. The idea of “innumerable” flukes being expelled in this way is
altogether out of the question.

The only genuine case in which any considerable number of Distomata,
of this species, have been observed in the human subject is the one
recently recorded by Dr Prunac. In this instance two flukes were vomited
along with blood immediately after the administration of salines (sel
de Seignette), and about thirty were passed per anum. On the following
day, some tapeworm proglottides having been evacuated, both salts and
male-fern extract were administered. This caused the expulsion of an
entire tapeworm, and also about twenty more flukes. Notwithstanding
this successful treatment the hæmatemesis returned in about a month,
when, finally, three more flukes were vomited and the bleeding ceased.
Had not the parasites been submitted for identification to a competent
observer (Prof. Martins, of Montpellier), some doubt might have been
entertained as to the genuineness of this remarkable case. In reference
to Dr Prunac’s comments on the facts of fluke-parasitism in man, I will
only remark that Dr Kerr’s Chinese cases, to which he refers, were
probably due to _Distoma crassum_ and not to _D. hepaticum_. The Chinese
flukes will be noticed below.

BIBLIOGRAPHY (No. 3).--Full references to details of the cases by
Partridge, Fox, and Harris are given in Appendix B. to Lankester’s
Edit. of _Küchenmeister’s_ Manual. See also the works of Davaine and
_Leuckart_ (_l. c._ Bibl. No. 1).--_Carter, H. V._, “Note on _Distoma
hepaticum_” (from a patient under the care of Mr Pandoorung), ‘Bombay
Med. and Physical Soc. Trans.’ (Appendix), 1862.--_Chabert, J. X._
(quoted above). Murchison, C., ‘Clinical Lectures on Diseases of the
Liver,’ (2nd Edit., Appendix), London, 1877.--_Prunac_, De la Douve ou
Distome hépatique chez l’homme; in ‘Gazette des Hôpitaux’ for December,
1878 (p. 1147). For further references in this work, see Bibliog. No. 49.

_Distoma lanceolatum_, Mehlis.--At least three instances of the
occurrence of this small fluke in the human body have been observed.
The authority for these cases rests, severally, with Bucholz, who
found them in the gall bladder in considerable numbers at Weimar; with
Chabert, who expelled a large number from the intestines of a girl in
France; and with Küchner, who obtained forty-seven specimens from a
girl in Bohemia. Probably many similar instances have been overlooked,
and Küchenmeister hints that Duval’s parasites (above mentioned) may
have been this species. Although this worm will again be incidentally
noticed in connection with bovine parasites (and its ciliated larvæ
will also be referred to when discussing the characters of the embryo
of Bilharzia), I here subjoin a diagnosis of the characters of the
adult parasite. The lancet-shaped liver fluke is a small flat helminth,
measuring rather more than the third of an inch in length, and about
one line and a half in breadth, being also especially characterised by
its lanceolate form; the widest part of the body corresponds with a
transverse line drawn across the spot where the vitellaria terminate
below, and from this point, on either side, the width of the animal
becomes gradually narrowed towards the extremities; both ends are
pointed, but the inferior or caudal one more obtusely than the anterior
or oral end; the general surface is smooth throughout, and unarmed; the
reproductive orifices are placed in the central line immediately in
front of the ventral sucker, and below the point at which the intestine
bifurcates; the oral sucker is nearly terminal, and 1/50″ in breadth,
the ventral acetabulum being about the same diameter; the testes form
two lobed organs placed one in front of the other in the middle line
of the body and directly below the ventral sucker; the uterine canal
is remarkably long, forming a series of tolerably regular folds, which
occupy the central and hinder parts of the body, reaching almost to
the caudal extremity. The vitelligene glands cover a limited space, on
either side of the centre of the body near the margin. The _foramen
caudale_ communicates with a contractile vesicle, which passes upwards
in the form of a central trunk-vessel, early dividing into two main
branches; these latter reach as far forwards as the œsophageal bulb,
opposite which organ they suddenly curve upon themselves, retracing
their course for a considerable distance backwards; the digestive canals
are slightly widened towards their lower ends, which occupy a line
nearly corresponding with the commencement of the lower fifth of the
body; the ova are conspicuous within the uterine folds, which present a
dark brownish color in front, passing to a pale yellow color below.

[Illustration: FIG. 1.--The lancet-shaped fluke (_Distoma lanceolatum_),
showing the disposition of the digestive and reproductive organs
internally. Viewed from behind; mag. about 12 diameters. After
Blanchard.]

In reference to Kichner’s remarkable case I reproduce an abstract of it
from Leuckart’s account (‘Die menschlichen Parasiten,’ Bd. i, s. 608),
the original particulars of which were communicated to Leuckart by Dr
Kichner himself:--

“Dr Kichner’s patient was a young girl, the daughter of the parish
shepherd at Kaplitz, having been accustomed to look after the sheep
ever since she was nine years old. The pasture where the animals
fed was enclosed by woods, being traversed by two water dykes, and
being, moreover, also supplied by ten little stagnant pools. These
reservoirs harboured numerous amphibia and mollusks (such as _Lymnæus_
and _Paludina_), and the child often quenched her thirst from the half
putrid water. Probably she also partook of the watercresses growing in
the ditches. At length her abdomen became much distended, the limbs much
emaciated, and her strength declined. Half a year before death she was
confined to her bed, being all the while shamefully maltreated by her
step-mother. Dr Kichner only saw her three days before her death, and
ascertained that she had complained of pain (for several years) over the
region of the liver. A _sectio cadaveris_ was ordered by the Government,
when (in addition to the external evidences of the cruel violence to
which the poor creature had been subjected) it was found that she had
an enormously enlarged liver, weighing eleven pounds. The gall-bladder
which was very much contracted and nearly empty, contained eight calculi
and forty-seven specimens of the _Distoma lanceolatum_, all of which
were sexually mature.”

As I have remarked in a former comment on this singular case, one can
have no difficulty in arriving at the conclusion that these parasites
were obtained from the girl’s swallowing trematode larvæ, either in
their free or in their encysted condition. Leuckart says it was not
possible to ascertain whether the parasites had any connection with the
gall-stones, or whether the two maladies, so to speak, were independent
of each other; yet this question might possibly have been solved if the
calculi had been broken up in order to ascertain their structure. It
is just possible that dead distomes may have formed their nuclei, and
if so, the circumstance would, of course, point to the worms as the
original source of the malady.

So far as I am aware, the actual transformations undergone by the
larvæ of _Distoma lanceolatum_ have not been observed. The _Planorbis
marginatus_ has been confidently referred to as the intermediate bearer
of the cercariæ of the common fluke, and Leuckart supposes that the same
mollusk harbours the larvæ of this species. The ciliated embryos carry
a boring spine or tooth, and it is most probable that the higher larvæ
are similarly armed.

BIBLIOGRAPHY (No. 4).--_Kichner_ (see _Leuckart_), quoted
above.--_Cobbold_, ‘Entozoa’ (p. 187).--The case by Bucholz (reported as
one of _Fasciola hepatica_) is given by _Jördens_ in his work (quoted by
Diesing and Leuckart) ‘Entomologie und Helminthologie des menschlichen
Körpers,’ (s. 64, tab. vii, fig. 14), 1802.--_Chabert’s_ French case is
quoted by _Rudolphi_ in his ‘Entozoorum sive vermium,’ &c. (_loc. cit._,
Bibl. No. 1), p. 326, 1808.

_Distoma crassum_, Busk.--This large species was originally discovered
by Prof. Busk in the duodenum of a Lascar who died at the Seamen’s
Hospital, 1843. It, however, remained undescribed until 1859, when, with
the discoverer’s approval, I gave some account of it to the Linnean
Society.

Of the fourteen original specimens found by Mr Busk, several have been
lost. The one that he himself gave me I handed over to Prof. Leuckart,
and it is figured in his work (‘Die mensch. Par.,’ s. 586). A second
is preserved in the museum attached to the Middlesex Hospital, and a
third is contained in the Museum of the Royal College of Surgeons. This
last-named specimen is the best of the original set. It supplied me with
the few details of structure figured in outline in my ‘Introductory
Treatise’ (fig. 42, p. 123), published in 1864; and it also in part
formed the basis of the description of the species communicated to
the Linnean Society in June, 1859 (“Synopsis of the Distomidæ,” p. 5,
‘Proceedings,’ vol. v). The late Dr Lankester, it is true, was the first
to give a distinctive title to this entozoon (_Distoma Buskii_); but
as the discoverer objected to this nomenclature, and as Dr Lankester’s
proposed terms were unaccompanied by any original description, I
requested Mr Busk to suggest a new name for the worm, which he
accordingly did. As I subsequently pointed out, Von Siebold had already
employed the compound title _Distoma crassum_ to designate a small fluke
infesting the house-martin (_Hirundo urbica_); but for reasons similar
to those which contributed to set aside Dr Lankester’s nomenclature, the
title adopted in my synopsis at length came to be recognised by Leuckart
and by other well-known helminthologists. Before this recognition took
place, Dr Weinland, of Frankfort, had so far accepted Lankester’s
nomenclature as to call the species _Dicrocœlium Buskii_. In my judgment
there are no sufficient grounds for retaining Dujardin’s genus. Further,
I may observe that, in addition to the above-mentioned specimens, two
others are preserved in the Museum at King’s College. Thus, only five
out of the fourteen specimens are still in existence.

No well-authenticated second instance of the occurrence of this worm
took place until the year 1873, when a missionary and his wife from
China consulted Dr George Johnson respecting parasites from which they
were suffering. After a brief interval, both of Dr Johnson’s patients
were by an act of courtesy on the part of this eminent physician placed
under my professional care. I need hardly add that Dr Johnson had from
the very first recognised the trematode character of the parasites. From
the patients themselves I ascertained that they had been resident in
China for about four years. During that period they had together freely
partaken of fresh vegetables in the form of salad, and also occasionally
of oysters, but more particularly of fish, which, in common with the
oysters, abound in the neighbourhood of Ningpo. From their statements it
appeared to me that to one or other of these sources we must look for
an explanation of the fact of their concurrent infection. Fluke larvæ,
as we know, abound in mollusks and fish; but whether any of the forms
hitherto found in oysters or in fish have any genetic relation to the
flukes of man, is a question that cannot very well be settled in the
absence of direct experimental proof. I should add that it was not until
after their visit to the interior of the country, some 130 miles distant
from Ningpo, that the symptoms (which Dr Johnson in the first instance,
and myself subsequently, considered to have been due to the presence
of the parasites) made their appearance. Whilst in the country the
missionary and his wife freely partook of freshwater fish, and on one
occasion they received a quantity of oysters that had been sent up from
Ningpo. The husband assured me that the fish were always thoroughly well
cooked.

If it be asked what were the symptoms produced, I can only furnish
such few and hitherto unpublished particulars as the missionary
himself supplied. I need hardly say that he was a highly cultured and
intelligent gentleman, since only such persons are chosen for missionary
work in China.

From inquiries made by me on the 29th of January, 1875, I learnt
that they left Ningpo in November, 1872, and travelled thence 130
miles into the interior of the country. In the following September,
or about ten months subsequently, the missionary was attacked with
diarrhœa, which persisted until expulsion of some of the parasites had
occurred. According to the patient’s statements this result, so far,
was entirely due to his having been placed on a milk diet; this course
of treatment having been recommended by Dr Henderson, of Shanghae. The
patient himself always suspected the presence of intestinal worms of
some sort or other, although a Japanese doctor laughed at the idea of
such a thing. Some other doctor treated this missionary for parasites,
administering both male-fern and santonine without effect.

It was not until several months had elapsed that his wife was attacked
with diarrhœa. In both cases there was more or less flatus. The motions
were white, and there were other indications implying that the liver was
affected. Later on, symptoms of indigestion, with heartburn, set in and
became very severe. Streaks of blood appeared in the fæces, but there
was no dysentery. For the most part these symptoms were attributed to
the effects of climate.

When, in the month of February, 1875, I saw the missionary a second
time, professionally, I found that all the old symptoms had returned.
He had a foul tongue, the surface of the body was cold, he felt
chills, and the pulse, though regular, registered ninety-six to the
minute. Indigestion, nausea, headache, and diarrhœa had reappeared.
Notwithstanding these febrile symptoms, so satisfied was the patient
himself that all his ailments were entirely due to the presence of
parasites, that I felt inclined to take the same view of his case.
Accordingly my attention was principally directed to an effort for their
expulsion; and in this view I ordered an aloetic pill followed by a
castor-oil emulsion. This having no effect, I subsequently prescribed
aloes and assafœtida pills, followed by scammony mixture. The action
of the latter drug did not occasion griping, but, although efficient,
led only to negative results. I should mention that in the patient’s
judgment none of the vermifuges administered to him at any time had
exerted any influence in the expulsion of the flukes. He was still
thoroughly impressed with the notion that the milk diet, ordered by Dr
Henderson, was the sole cause of their expulsion.

As even a missionary could not live by milk alone I insisted upon a more
substantial diet. The milk, indeed, had occasionally been supplemented
by Liebig’s extract of meat and by light farinaceous food. When I last
saw him neither he nor his wife had passed any more flukes, but they
did not feel satisfied that no more guests remained. Somewhat improved
in general health, the missionary resolved to go back to his duties in
China. I expressed my fears, however, that his strength would prove
unequal to the work.

From the size and almost leathery texture of the two flukes which were
in the first instance submitted to my notice, I at once recognised the
species; but as they were spirit-specimens, I requested that if any more
examples were obtained they should be sent to me in the fresh state.
Fortunately others were brought in a few days, when, from an examination
conducted whilst they were still fresh, I was able to make out several
details of structure which had hitherto escaped notice. Altogether I
secured seven specimens, three of them being in a mutilated condition.
In what way these mutilations (as shown by my dried specimens) occurred
I have not been able to make out, either by personal observation or by
questioning the bearers. Two of the parasites look as though portions
had been carefully excised near the centre. The new facts I have gleaned
were derived from the examination of two comparatively small specimens,
one of which, dried, has, by Prof. Rolleston’s desire, been deposited
in the anatomical department of the University Museum at Oxford. When
I took occasion to bring some of the new specimens under Mr Busk’s
attention, he at once recognised them as referable to the species he had
long ago discovered.

The earliest literary notice of _Distoma crassum_ appeared in Dr Budd’s
classical treatise ‘On Diseases of the Liver;’ and in it the author
correctly stated, from data supplied by Mr Busk, that these human flukes
were “much thicker and larger than those of the sheep,” being, it is
added, from “an inch and a half to near three inches in length.” The
longest of my recent specimens, however, scarcely exceeds two inches,
whilst the smallest and most perfect (the one at Oxford) measures less
than an inch from head to tail. The greatest width of my broadest
specimen is little more than half an inch, or 9/16″. None of the twelve
examples that I have examined approach the length of three inches; but
Mr Busk assured me that, judging from his recollection, some of his
specimens were even longer than that. I fear, nevertheless, that the
estimate given in my Synopsis is somewhat exaggerated; at all events it
is so for average specimens.

[Illustration: FIG. 2.--The large human fluke (_Distoma crassum_) _a_,
Oral sucker; _b_, intestine; _c_, cæcal end of same; _d_, reproductive
papilla; _e_, uterine rosette (the folds of which are not branched);
_f_, one of the folds (in profile); _g_, vitellarium; _h_, hernial
protrusion (the result of an injury to the specimen); _i_, upper testis;
_j_, streaks or layers of seminal fluid which have escaped by rupture
and assumed a branched appearance; _k_, lower testis uninjured (but
slightly altered in outline from flattening); _l_, ventral sucker.
Magnified 2 diameters. Original.]

The new anatomical facts made out by me bear reference principally to
the reproductive apparatus. What else I have observed is for the most
part confirmatory of the statements made by Mr Busk. In particular,
his brief account of the position and character of the digestive
organs was not only confirmed by my earlier examinations, but is now
re-verified. In the representation given in my ‘Introduction’ I showed
in dotted outline two large organs which I supposed to be the testes.
I distinctly observed radiating lines proceeding from the centre in
each; but I could not discover the slightest trace of any limiting
border to either organ. I now found in the same position two nearly
circular flattened masses with clearly defined limits (_i_, _k_). No
doubt could be entertained as to the testicular character of the lower
organ (_k_). In the original drawing I further indicated the presence
of a third and much smaller globular mass, which I termed the ovary;
but what I supposed to represent this organ in the particular specimen
from which the accompanying illustration was drawn turns out to be
merely a hernial protrusion resulting from injury (_h_). The radiating,
broad, and branching seminal ducts are beautifully distinct in one of
my specimens, forming the most attractive feature of the parasite’s
organisation (_k_). In consequence of injury to the specimen which is
here drawn, the upper testis (_i_) displays no seminal tubes. I made out
the female reproductive organs with more completeness. In the outline
drawing given in my introductory treatise I had indicated the probable
position of the uterine folds; reducing the organ to the simplest
expression of what I concluded must obtain in the normal condition. My
conjecture was perfectly correct. The uterus consists of irregularly
folded tubes, which, though here and there apparently branching from
a central tube, are in reality folded evenly upon themselves. The
oviduct can be distinctly traced to its outlet in the reproductive
papilla, which, as usual in true Distomes, is placed in the middle line,
immediately above the ventral sucker. In my examination of Mr. Busk’s
original specimens I could not find the slightest trace of vitelligene
organs; but in my fresh examples I not only obtained proof that these
organs were largely developed, but that their limitations could be fixed
with accuracy (_g g_). They consisted of two large elongated masses, one
on either side of the body, occupying about two thirds of the entire
length of the parasite. Their yolk-vesicles were distinctly seen; but
the main efferent canals were only here and there traceable. Clearly,
the position and character of the yolk-forming glands of this large
human fluke are quite unlike those of any of its congeners. This fluke
is a remarkably fine species, and, when viewed in the fresh state with
a powerful pocket-lens, presents a most striking appearance. I did not
observe any cutaneous spines. I found the eggs to present an average
long diameter of about 1/200″, by 1/330″ in breadth. They are therefore
somewhat smaller than those of the common fluke. In the specimen
preserved in the Hunterian Museum there was complete evidence of the
presence of an excretory outlet at the caudal extremity; but I did not
succeed in finding any trace of the water-vascular system higher up. I
have no doubt, however, that it exists.

As regards the affinities of _Distoma crassum_, it is clear that this
Trematode has little in common either with the liver-fluke of cattle
and sheep (_Fasciola hepatica_), or the still larger species obtained
by me from the giraffe (_Fasciola gigantea_). The simple character
of the digestive tubes obviously connects it more closely with the
lancet-shaped fluke (_Distoma lanceolatum_), the last-named parasite
being, as already shown, an occasional resident in the human liver,
where its presence, moreover, undoubtedly contributed towards the
production of the fatal result.

In my remarks on the missionary’s diet it is hinted that the Ningpo
oysters may have played the _rôle_ of intermediary bearers to the
parasite in question; and as tending in some measure to strengthen this
notion, it should be borne in mind that Mr. Busk’s original fluke-bearer
came from the east. It is not improbable that the Lascar host may have
partaken of the same particular species of fish or shell-fish that the
missionary and his wife partook of. Be that as it may, the frequency
of the occurrence of Trematodes and their larvæ in marine mollusks is
well known. According to Woodward, several species of oyster are sold
in the Indian and Chinese markets. Thus, it would require the skill of
a malacologist to determine the particular species of _Ostrea_ to which
the Ningpo oysters should be referred.

Mons. Giard is of opinion that the singular larvæ known as _Bucephali_
attain sexual maturity in sharks and dog-fishes; therefore it is
extremely unlikely that the _Bucephali_ should have been in any way
concerned in the infection of our missionary and his wife; nevertheless
there remains the probability that these human bearers swallowed
other kinds of Trematode larvæ when they consumed the Ningpo oysters.
Moreover, if it should happen that none of the other larvæ occurring in
oysters are capable of developing into flukes in the human territory,
it yet remains highly probable that some one or other of the various
encysted (and therefore sexually immature) Trematodes known to infest
marine fishes will turn out to be the representative of our _Distoma
crassum_. In this connection we must not forget that the flesh of
the _Salmonidæ_ forms the probable source of human _Bothriocephali_;
and there is some likelihood that salt-water fishes, if not actually
the primary, may become (after the manner explained by M. Giard) the
secondary intermediary bearers of fluke-larvæ. At all events, I am
inclined to look to the Ningpo oysters, or to some other of the various
species of marine shell-fish sold in eastern markets, as the direct
source of _Distoma crassum_; for, in addition to the bucephaloid
cercarians, we have abundant evidence of the existence of other and more
highly developed fluke-larvæ in marine bivalve mollusks.

In this connection I will only further observe that we possess very
little knowledge of the parasites which take up their abode in the
viscera of savages. This ignorance results partly from the fact that
these untutored races, as proved by the statements of Kaschin and
others, actually, in the matter of severe symptoms, suffer much less
from the presence of intestinal worms than their civilised fellow-men
do. The subject is worthy of further attention, but no one, so far as I
am aware, has cared to institute the necessary inquiries in a methodical
way. I strongly suspect that several of the human parasites which we
now consider to be rare would be found to be abundant if by means of
post-mortem examinations and other methods of investigation we could
be made acquainted with the facts of helminthism as they occur amongst
the raw-flesh and fish-eating savage tribes. Of course any person,
notwithstanding the utmost care and cleanliness, as in the cases before
us, may contract a noxious parasite; nevertheless, speaking generally,
it may be said that the measure of internal parasitism affecting any
given class of people bears a strict relation to the degree of barbarism
shown by such persons in their choice of food and drink, and in their
manner of eating and drinking. This statement, if true, is not destitute
of sanitary importance; moreover, it applies not alone to ourselves, but
also to all the domesticated animals that serve our wants. Cleanliness
is just as necessary for their welfare as for our own.

In the spring of 1878 my patients returned from China. They had
experienced fresh attacks from the parasite; moreover, one of their
children, a little girl, was also victimised by the same species
of fluke. Thus, in one family I have encountered three cases of
fluke-helminthiasis due to _Distoma crassum_! One of the worms passed by
the little girl _per anum_ is now in my possession. It not only shows
the upper testis perfectly, but also the many times transversely folded,
simple, uterine rosette which is certainly not branched. There are also
traces of an organ which I take to be the cirrhus-pouch; but I have
never seen the penis protruded externally.

For the purposes of diagnosis I subjoin the following characters. The
_Distoma crassum_ is a large, flat helminth varying from an inch and a
half to two and a half inches in length, and having an average breadth
of five eighths of an inch; it is especially also characterised by its
uniform and considerable thickness, combined with the presence of a
double alimentary canal which is not branched; the body is pointed in
front, and obtusely rounded posteriorly; the integument being smooth
and unarmed; the reproductive orifices placed immediately above the
ventral sucker; the testes form two large rounded organs, situated below
the uterine rosette, and disposed in the middle line, one in front of
the other; the uterine folds occupy the front part of the body; near the
lateral margins there are two large vitelligene glands, one on either
side of the intestinal tube; the excretory organ probably consists of a
central trunk with diverging branches, opening below.

BIBLIOGRAPHY (No. 5).--_Budd_, original notice in his ‘Diseases
of the Liver,’ 2nd edition, quoted by Lankester in Appendix B to
Küchenmeister’s ‘Manual of Parasites,’ p. 437, 1857.--_Cobbold, T. S._,
“Synopsis of the _Distomidæ_,” in ‘Journ. of the Proceed. of the Linnean
Soc.,’ vol. v, Zool. Div., 1860 (original description p. 5).--_Idem_,
‘Entozoa,’ p. 193, 1864.--_Idem_, “Remarks on the Human Fluke Fauna,
with especial reference to recent additions from India and the East,”
the ‘Veterinarian,’ April, 1876.--_Idem_, “On the supposed Rarity,
Nomenclature, Structure, Affinities, and Source of the large Human Fluke
(_D. crassum_),” ‘Linn. Soc. Journ.,’ vol. xii, Zool. Div., 1876, p. 285
_et seq._--_Idem_, “Observations on the large Human Fluke, with notes
of two cases in which a missionary and his wife were the victims,” the
‘Veterinarian,’ Feb., 1876.--_Idem_, “The new Human Fluke,” in a letter
published in the ‘Lancet,’ Sept., 1875.--_Leidy_, in ‘Proceed. Acad.
Nat. Sciences of Philadelphia;’ see also Dr McConnell’s paper quoted
below (Bibl. No. 6).--_Leuckart_, l. c., Bd. I, s. 560.--_Weinland_, l.
c. (Bibl. No. 2), Appendix, p. 87.

_Distoma Sinense_, Cobbold.--The discovery of this species is due to
Prof. J. F. P. McConnell, who “on the 9th of Sept., 1874, found a large
number of flukes in the liver of a Chinese, obstructing the bile ducts.”
The species measures 7/10″ in length, by 1/7″ in breadth, the eggs
being 1/833″ by 1/1666″. Dr McConnell showed in his original memoir
that the worm cannot well be confounded with _Fasciola hepatica_, with
_Distoma lanceolatum_, or with _D. conjunctum_. In this conclusion he
was supported by Dr T. R. Lewis, who examined the specimens with him.
In a letter communicated to the ‘Lancet,’ quoted above, I proposed
the nomenclature here given; but Prof. Leuckart, unaware of this
step, afterwards suggested the terms _Distomum spatulatum_. Later on
I received numerous specimens from Calcutta, the examination of which
enabled me to confirm the accuracy of the original description. As
regards the male organs in the subjoined figure, it will be seen, by
comparing the lettering and references, that I have interpreted the
facts of structure somewhat differently from Prof. McConnell.

[Illustration: FIG. 3.--The Chinese fluke (_Distoma Sinense_). _a_, Oral
sucker; _b_, œsophageal bulb; _c_, intestine; _c′_, cæcal end; _d_,
ventral sucker; _e_, genital pore; _f_, uterine folds; _g_, ovary; _h_,
vitellarium; _i_, vitelligene duct; _k_, upper seminal reservoir; _l_,
testes; _m_, lower seminal pouch; _o_, vas deferens; _p_, pulsatile
vesicle; _p′_, water vessel. After McConnell.]

In the month of December, 1874, a Chinese died in the Civil Hospital
at Port Louis, Mauritius, whilst he was under the care of Dr William
Macgregor, chief medical officer of the Colony of Fiji. The post
mortem revealed the presence of a very great number of flukes in the
bile-ducts. Dr Macgregor described these parasites with great care, and
having favored me with a copy of his manuscript I at once recognised the
worms to be identical with the species discovered by McConnell. I also
received through Dr Henry Clark, of Glasgow, two Mauritius specimens,
which when compared with the Calcutta examples proved to be specifically
identical. Dr Macgregor’s paper, communicated to the Glasgow
Medico-Chirurgical Society, gives full particulars of the helminthiasis
associated with this parasite, whilst both his and Prof. McConnell’s
account of the structure of the worm are remarkably complete in details,
and well illustrated. It is not a little curious to notice that although
these parasites were obtained in countries far removed from China, they
were in both instances taken from Chinese; moreover, from the statements
of Macgregor, it appears very probable that the parasites in question
are a common source of liver disease. Without doubt oriental habits are
eminently favorable to fluke infection, for we are now acquainted with
four species of flukes whose geographical range is limited to eastern
parts.

BIBLIOGRAPHY (No. 6).--_McConnell, J. F. P._, “Remarks on the Anatomy
and Pathological relations of a new species of Liver-fluke,” ‘Lancet,’
Aug. 1875; repr. in the ‘Veterinarian,’ Oct., 1875; also in the
‘Lancet,’ March 16th, 1878, p. 406.--_Macgregor, W._, “A new form of
Paralytic Disease, associated with the presence of a new species of
Liver Parasite (_Distoma Sinense_),” ‘Glasgow Med. Journ.’ for Jan.,
1877; also in the ‘Lancet’ for May 26th, 1877, p. 775.--_Cobbold, T.
S._, in a note to the ‘Lancet,’ Sept., 1875, and in the Appendix to
Macgregor’s paper, p. 15, 1877.--_Leuckart, R._, l. c., Bd. ii, s. 871,
1876.

_Distoma conjunctum_, Cobbold.--The little fluke which I first
discovered in the gall-ducts of an American fox (_Canis fulvus_) was
fourteen years afterwards obtained from pariah dogs in India by Dr. T.
R. Lewis (1872); but it remained for Prof. McConnell to show that this
entozoon also invades the human subject (1874). A second instance of its
occurrence in man was recorded in 1876. We all figured the worm, and in
respect of general details our descriptions for the most part agreed
(fig. 56). The worms from the dog and fox gave an average of 1/4″ in
length, but the majority of those found by McConnell in man were fully
3/8″ from head to tail.

Writing in the spring of 1876 Dr McConnell says:--“In the ‘Lancet’ for
the 21st of August, 1875, I published the description of a new species
of liver-fluke found in the bile-ducts of a Chinaman (_sic_) who died in
this hospital. Dr Spencer Cobbold has very kindly interested himself
in this discovery, and proposed the name of _Distoma Sinense_ for the
new fluke. This discovery (in September, 1874) has stimulated me to pay
still greater attention to the morbid conditions of the biliary canals
in our post-mortem examinations; but, although more than 500 autopsies
have been conducted since that date, I have not met with another
instance of distomata in the liver until within the last fortnight. On
the 9th of January, 1876, in examining the liver of a native patient who
had died in the hospital, I again found a large number of flukes in the
bile-ducts, and having carefully examined many specimens, I recognise
the species as the _D. conjunctum_ of Cobbold. Dr Cobbold discovered
this fluke in 1858; but, as far as I am aware, the human liver has never
hitherto been found infested by these parasites, and this will give
general interest and importance to the following case.”

“Jamalli Khan, a Mahommedan, aged twenty-four, admitted into the
hospital on the 25th of December, 1875. He is a resident of Calcutta,
and an ordinary labourer (coolie). He states that he had been suffering
from ‘fever’ for the last two months, at first intermittent in
character, but for the last seven days more or less continued. He is
much emaciated and reduced in strength. Complains of pain on pressure
over the liver and spleen; the latter can be felt much enlarged,
reaching downwards to nearly the level of the umbilicus; the lower
border of the liver, however, can only just be felt below the ribs.
Temperature on evening of admission 101° F. Conjunctivæ are anæmic,
but not jaundiced. Has also a little bronchitis. The fever continued
with slight remissions for ten days (January 4th, 1876), the highest
diurnal temperature (in the afternoon) varying from 103° to 104° F.; it
then abated, but dysentery set in. He began to pass six or eight stools
in the twenty-four hours, attended with much griping, and containing
varying quantities of blood-tinged, gelatinous mucus. These became more
frequent, in spite of treatment, during the next three days, and on the
8th of January he was manifestly sinking; passed his evacuations into
the bedclothes, became cold and collapsed, and died in this state that
same evening.

“A post-mortem examination was made on the following morning, thirteen
hours after death. All the organs of the body were found more or less
anæmic, but exhibited nothing remarkable with the following exceptions.
The lungs towards their posterior margins and bases were dark, but still
spongy and crepitant. The spleen was found greatly enlarged, heavy;
capsule tense and stretched; substance soft, reddish brown, irregularly
pigmented; weight 1 lb. 13 oz. The liver was of about normal size; its
surfaces smooth, the capsule slightly hazy looking. Hepatic substance
firm, but abnormally dark, and the bile-ducts particularly prominent
and thickened. Numbers of small distomata escaped from the incisions
made into the organ, and could be seen protruding from the dilated
biliary canals. The gall-bladder was filled with thick greenish-yellow
bile, measuring about an ounce and a half, but containing no parasites,
and no ova even could be detected on microscopical examination of this
bile and of scrapings from the lining membrane of the gall-bladder.
The cystic duct was free from obstruction. The condition of the common
choledic duct could not so well be ascertained, as the liver had been
removed from the abdominal cavity before anything extraordinary had been
detected in its condition, but, so far as it could be examined, it was
found patent; the duodenal mucous membrane was well bile-stained, and
there was evidence of biliary colouring matter in the fæcal contents
of the bowels. On carefully dissecting out, and then laying open, the
biliary ducts in a portion of the right lobe of the liver (the rest
being preserved entire), numbers of distomata were found within them,
lying singly, flattened, and generally with the anterior extremity,
or “oral sucker,” directed towards the periphery of the organ, the
posterior extremity towards its centre; or in twos, threes, or even
little groups of fours, variously coiled upon themselves or upon each
other. The lining membrane of the biliary canals was found abnormally
vascular, its epithelial contents abundant (catarrh?), and, among these,
ova could be detected under the microscope. Sections of the liver,
hardened and then examined in glycerine, showed fatty infiltration of
the lobular structure, but not to any advanced degree; the bile ducts
considerably dilated, their walls thick and hypertrophied, but nothing
else abnormal, or in any way remarkable. The weight of the liver was 3
lbs. In the transverse and descending colon numerous indolent-looking,
shallow, pigmented ulcers were found, and in the rectum others evidently
more recent and highly injected. The submucous tissues throughout were
abnormally thickened. The intestinal contents consisted of only about
three ounces of thin yellowish (bilious) fæcal fluid, with small bits of
opaque mucus. This was carefully washed and examined, but no flukes were
discovered. About a dozen distomata escaped from the liver on making the
primary incisions, and quite twice this number was found subsequently
within the biliary canals. Only a portion of the right lobe has, as I
have said, been dissected, so that it may be confidently stated that
probably not less than a hundred of these flukes must have infested
this liver. All were found dead, but it must be remembered that the
autopsy was performed thirteen hours after the death of the patient.
It is remarkable that in this case, as in the one before described by
me, no distomata were found in the gall-bladder. The presence of these
parasites in the bile-ducts seems to have led to catarrhal inflammation
of their lining membrane and abnormal thickening and dilatation of
their walls, but there is no evidence of their having caused sufficient
obstruction to produce cholæmia, as in the case just referred to, and no
marked pathological change could be detected in the lobular structure of
the liver.”

After referring to the anatomical descriptions of the worm, as recorded
by myself (in ‘Entozoa’) and by Lewis (in the memoir quoted below),
Professor McConnell further observes that the addition of a few more
particulars seems necessary for the determination of the identity of the
species. He then gives the following characters:

“Body lanceolate, anterior and posterior extremities pointed, the latter
obtusely. Surface covered with minute spines or hairs. Average length
3/8″ (three eighths of an inch); average breadth 1/10″. ‘Ventral’ sucker
slightly smaller than ‘oral.’ Reproductive papilla or genital orifice
placed a little above and to one side of the former. Alimentary canal
double and unbranched. Uterine folds and ovary placed in the median
line, and above the male generative organs, the latter consisting of two
very distinct globular bodies or testes. Ova of the usual type, _i. e._
oval in outline, having a double contour, and granular contents; average
length, 1/750″; average breadth, 1/1333″. The only point of note is that
the average length of these flukes is greater than that of the same
species found by the authors above referred to. The _D. conjunctum_ in
the American fox, and in the pariah dog, has an average length of 1/4″;
only two or three specimens of this size were found in this liver, and
these showed evidences of immaturity; a few were found 1/2″ in length;
but the great majority exactly 3/8″. The anatomical characters are
otherwise precisely identical.”

Professor McConnell concludes his communication by a remark in reference
to the common source of infection shared by mankind and dogs in India.
The occurrence, however, of this entozoon in an American red fox points
to a very wide geographical distribution of the species. It is hardly
likely that the fox, though dying in the London Zoological Society’s
Menagerie, should have contracted the parasite in England. In the second
half of this work I shall reproduce my original drawing (fig. 56) from
the ‘Linnean Transactions;’ but I may refer to my Manual (quoted below)
for a reproduction of McConnell’s figure. In my original specimens the
integumentary spines had fallen, probably as a result of post-mortem
decomposition.

BIBLIOGRAPHY (No. 7).--_Cobbold, T. S._, “Synopsis of the Distomidæ” (l.
c.), 1859; and in “Further Observations on Entozoa, with experiments,”
‘Linn. Trans.,’ vol. xxiii (tab. 33, p. 349), 1860.--_Idem_, “List
of Entozoa, including Pentastomes, from animals dying at the Zool.
Soc. Menagerie between the years 1857-60,” ‘Proceed. Zool. Soc.,’
1861.--_Idem_, ‘Entozoa,’ p. 20, pl. ii, 1864; and in “Manual
of the Internal Parasites of our Domesticated Animals,” p. 81,
1873.--_Lewis, T. R._, and _Cunningham, D. D._, in a footnote to their
‘Microscopical and Physiological Researches,’ Appendix C., ‘Eighth Ann.
Rep. of the San. Comm. with the Govt. of India,’ p. 168, Calcutta,
1872.--_McConnell, J. F. P._, “On the _Distoma conjunctum_,” in the
‘Lancet’ for 1875-76, quoted above; reprinted in the ‘Veterinarian,’
1876; also (a second case) in the ‘Lancet’ for March 30th, 1878, p. 476.

_Distoma heterophyes_, Von Siebold.--This minute parasite, measuring
only 3/4 of a line in length, was discovered by Dr Bilharz, of Cairo,
in the intestines of a lad, post-mortem, in the year 1851. A second
similar instance occurred, when several hundred examples were collected
and afterwards distributed amongst the helminthologists of Europe.
Through the kindness of Leuckart two of the worms eventually reached
myself. From one of these the accompanying figure was drawn. For the
purpose of supplying a full diagnosis I have elsewhere described this
worm as presenting an oblong, pyriform outline, attenuated in front, and
obtusely rounded behind; body compressed throughout, the surface being
armed with numerous minute spines, which are particularly conspicuous
(under the microscope) towards the head; oral and ventral suckers
largely developed, the latter being near the centre of the body, and
about twice the diameter of the former; pharyngeal bulb distinct and
separate from the oral sucker, and continued into a long œsophagus,
which divides immediately above the ventral acetabulum; intestinal tubes
simple, gradually widening below and terminating near the posterior
end of the body; reproductive orifices inconspicuous, but evidently
placed below and a little to the right of the ventral sucker, at which
point they are surrounded by a special accessory organ, resembling a
supernumerary sucker; uterine folds numerous and communicating with
small but conspicuously developed vitelligene glands; testes spherical
and placed on the same level in the lower part of the body; ovary
distinct; aquiferous system terminating inferiorly in a large oval
contractile vesicle, the latter opening externally by a central _foramen
caudale_.

Apart from its minuteness, moreover, this trematode is especially
characterised by the possession of a very remarkable apparatus
surrounding the reproductive orifices. It consists of an irregularly
circular disk, measuring 1/125″ in diameter, and having a thick-lipped
margin, which supports seventy fish-basket-like horny ribs comparable
to the claw-formations seen in the genus _Octobothrium_. According to
Bilharz these ribs give off five little branches from their sides, but
Leuckart could not see them in his specimens. Leuckart estimated the
length of these horny filaments to be 1/1250″, whilst their breadth was
1/3570″. On the whole we may regard this organ as a complicated form of
“holdfast” designed to facilitate or give efficiency to the sexual act.
I may here also state that this structure is by no means unique; for,
if I mistake not, it exists in an equally developed degree in the young
trematode which Dr Leared found infesting the heart of a turtle. Leared
believed that he had found an ordinary distome; an opinion to which I
could not give my assent, seeing that the organ described by him as a
“folded, ventral sucker” presented a very different aspect to the oral
sucker displayed by the same animal. Without doubt, however, the organ
in his so-called _Distoma constrictum_ is analogous to the supplementary
“holdfast” existing in _Distoma heterophyes_. The views which I
originally advanced as to the source and condition of the parasite are
probably correct.

[Illustration: FIG. 4.--The small Egyptian fluke (_Distoma
heterophyes_), viewed from behind. The large ventral sucker,
supplementary disk, uterus, testes, simple divided intestine,
vitellarium, and pulsatile vesicle are conspicuous. Original.]

As regards the structure of _Distoma heterophyes_, I have only to add
that a special set of glandular organs is situated on either side of the
elongated œsophagus, but the connection between these organs and the
digestive apparatus has not been clearly made out. Leuckart compares
them to the so-called salivary glands found in _Distoma lanceolatum_,
and says, “The presence of such a glandular apparatus is also indicated
by the more ventral position of the oral sucker, and the development of
the cephalic margin.” The conspicuous contractile vesicle terminating
the excretory system is developed to an unusually large extent,
exhibiting in its interior multitudes of the well-known active molecular
particles. Lastly, I have only to add that the eggs of _Distoma
heterophyes_ measure 1/990″ in length by 1/666″ transversely.

BIBLIOGRAPHY (No. 8).--_Bilharz_, “Beitrag zur Helminth. humana,”
‘Zeitsch. für wissenschaftl. Zool.,’ s. 62, 1851.--_Cobbold_,
‘Entozoa,’ p. 195, 1864.--_Küchenmeister, F._, ‘Parasiten,’ 1855, s.
210, Eng. edit., p. 276, 1857.--_Leared_, “Description of _Distoma
constrictum_,” ‘Quarterly Journal of Micros. Science,’ new series, vol.
ii, 1862.--_Leuckart, R._, l. c., s. 613, 1863.--_Moquin-Tandon_, on the
Genus _Fasciola_, l. c., 1861.--_Weinland_, on _Dicrocœlium_, l. c., p.
86, 1858.

_Distoma ophthalmobium_, Diesing.--There is every reason to believe
that the small flukes found by Gescheid and Von Ammon in the human eye
were sexually immature worms, but since it cannot be decided as to what
adult species they are referable I prefer to notice them under the usual
title. Possibly these eye-worms may be referred to _D. lanceolatum_, as
suggested by Leuckart. However that may be, I deem it unnecessary to
repeat the details recorded in the treatises quoted below. The largest
examples measured only half a line or about one millimètre in length.

[Illustration: FIG. 5.--The eye fluke (_Distoma ophthalmobium_). Showing
the suckers and intestinal tubes. After Von Ammon.]

BIBLIOGRAPHY (No. 9).--_Cobbold_, ‘Entozoa,’ p. 191.--_Gescheid (D.
oculi humani)_, in Von Ammon’s ‘Zeitsch. f. Ophth.,’ iii, and also
in Ammon’s ‘Klin. Darstell. d. Krankheit d. Menschl. Auges.,’ vols.
i and iii.--_Küchenmeister_, Eng. edit., p. 287.--_Leuckart_, l. c.,
s. 610.--_Nordmann (Monostoma lentis)_, “Mikr. Beitr.,” Heft. ii,
‘Vorwort,’ s. ix, 1832.

_Tetrastoma renale_, Chiaje; _Hexathyridium pinguicola_, Treutler;
and _H. venarum_, Treutler.--Whether these forms are good species or
not, the fact that they were genuine parasites cannot, I think, be
disputed. The first-mentioned measured five lines in length, and was
found by Lucarelli in the urine. The second, eight lines long, was found
by Treutler in a small tumour connected with the ovary. The third,
measuring three lines in length, was twice found in venous blood, and
twice in the sputum of patients suffering from hæmoptysis.

BIBLIOGRAPHY (No. 10).--_Delle-Chiaje_, ‘Elmintografia Umana,’
1833.--_Bremser_ (l. c., Bibl. No. 2), s. 265, 1819.--_Cobbold_,
‘Entozoa’ (p. 204, et seq.).--_Dujardin_ (l. c., Bibl. No. 2), s. 265,
1819.--_Treutler_, ‘Obs. Path. Anat. ad Helm. Corp. Humani,’ p. 19,
1793.--_Zeder_, ‘Anleitung zur Naturg. der Eingeweidewürmer,’ s. 230,
1803.

_Amphistoma hominis_, Lewis, and McConnell.--The original account of
this species is based upon two finds. The first series of specimens was
procured from Dr J. O’Brien, of Gowhatty, and the second set from the
Pathological Museum of the Calcutta Medical College. Dr O’Brien and Dr
Curran together procured their specimens, post-mortem, from an Assamese.
There were hundreds of worms present in the vicinity of the ileo-colic
valve. The museum specimens were procured from a patient who died at the
Tirhoot gaol hospital in 1857. They were (say the authors) presented to
the museum by Dr Simpson, and in the catalogue their history was briefly
recorded as follows:

[Illustration: FIG. 6.--The human amphistome (_Amphistoma hominis_).
Longitudinal section. _a_, Oral sucker; _b_, pharyngeal bulb; _c_, nerve
ganglia; _d_, œsophagus; _e_, genital pore; _f_, vagina; _g_, ductus
ejaculatorius; _h_, ventral nerve cords; _i_, intestinal canal; _j_,
upper testis; _k_, water vessel; _l_, lower testis (ovary according
to Lewis); _m_, principal ducts of the vitellarium; _n_, branches of
the vitellary ducts; _o_, ventral pouch or bursa; _p_, caudal sucker.
Magnified 12 diameters. After Lewis.]

“The cæcum of a native prisoner who died from cholera in the Tirhoot
gaol hospital, with a number of peculiar and, probably, hitherto
unrecognised parasites, found alive in that part of the intestinal
canal.” (_Presented by Dr Simpson through Professor E. Goodeve._)

In continuation of their narrative, Drs Lewis and McConnell go on to
say that, “with reference to this preparation, the following very
interesting particulars from the ‘Annual Jail Report of Tirhoot’
for 1857 have been very kindly placed at our disposal by the
Surgeon-General, Indian Medical Department. The prisoner, Singhesur
Doradh, aged 30, was attacked with cholera on the 13th, and died on
the 14th of July, 1857. Had not been in hospital previously, and was
employed in cleaning the jail.”

The post-mortem examination was made three hours after death:--“Colon
externally livid, contracted; contains a little serous fluid with
flakes of mucus. Mucous membrane healthy except venous injection. In
the cæcum and ascending colon numerous parasites like tadpoles, alive,
adhering to the mucous membrane by their mouths. The mucous membrane
marked with numerous red spots like leech-bites from these parasites.
The parasites found only in the cæcum and ascending colon, none in the
small intestines.” This description is by Dr Simpson, who adds, “I
have never seen such parasites, and apparently they are unknown to the
natives. They are of a red colour, size of a tadpole, some young, others
apparently full grown, alive, adhering to mucous membrane,--head round,
with circular open mouth, which they had the power of dilating and
contracting. Body short and tapering to a blunt point.”

Drs Lewis and McConnell’s description of the worm is too long to be
quoted in full. The parasites measure 1/5″ to 1/3″ in length, by 1/8″ to
1/6″ in breadth. Science is much indebted to these eminent observers for
having unearthed the museum specimens and for recording the facts they
could gather. From a zoological point of view the most interesting fact
connected with Lewis’s amphistome is the existence of a gastric pouch.
This structure brings these human _Masuri_ into close relation with the
equine parasite which I have named _Gastrodiscus Sonsinoii_, and which
will be found illustrated in this work (fig. 62). In short, Lewis’s worm
appears like a transition form; the absence of gastric supplementary
suckerlets separating it from the new generic type.

BIBLIOGRAPHY (No. 11).--_Lewis, T. R., and McConnell, T. F. P.,_ “_Amph.
hominis_; a new parasite affecting Man,” ‘Proceedings of the Asiatic
Society of Bengal,’ Aug., 1876.

_Bilharzia hæmatobia_, Cobbold.--This remarkable parasite was discovered
by Bilharz in 1851. It was subsequently found by myself in an ape
(1857); other species of the same genus having since been detected by
Sonsino in the ox and sheep (1876). The human examples were originally
obtained from the portal system of blood-vessels. Afterwards they were
obtained by Bilharz, Griesinger, and others, from the veins of the
mesentery and bladder. It was shown that they were not only associated
with, but actually gave rise to a formidable and very common disease in
Egypt.

In 1864 Dr John Harley made the interesting announcement that he had
discovered specimens of this singular genus in a patient from the
Cape of Good Hope. He also showed that the entozoon was the cause
of the _hæmaturia_ known to be endemic at the Cape. Harley believed
his parasites to represent a new species (_Distoma capense_), but in
this view I showed that he was mistaken. His admirable contribution,
nevertheless, served not only to establish the wide range of this
parasite on the African continent, but also to throw much light upon
the subject of endemic helminthiasis. As this worm forms an almost
altogether exceptional type of fluke-structure, it became necessary
to supersede the original nomenclature proposed by Bilharz and Von
Siebold (_Distoma hæmatobium_). Accordingly I proposed the term
_Bilharzia_, whilst other helminthologists subsequently proposed various
titles (_Gynæcophorus_, Diesing; _Schistosoma_, Weinland; _Thecosoma_,
Moquin-Tandon). On various grounds, and chiefly on account of priority,
most writers have at length definitely accepted the nomenclature which
employed the discoverer’s name for generic recognition.

[Illustration: FIG. 7.--The blood fluke (_Bilharzia hæmatobia_). The
lower end of the female is withdrawn from the gynæcophoric canal of the
male. After Küchenmeister.]

The _Bilharzia hæmatobia_ may be described as a trematode helminth
in which the male and female reproductive organs occur in separate
individuals; the male being a cylindrical vermiform worm, measuring only
half an inch or rather more in length, whilst the female is filiform,
longer, and much narrower than the male, being about four fifths of
an inch from head to tail; in both, the oral and ventral suckers are
placed near each other at the front of the body; in the male the suckers
measuring 1/100″, in the female 1/314″ in diameter; in either, the
reproductive orifice occurs immediately below the ventral acetabulum.
The comparatively short, thick, and flattened body of the male is
tuberculated and furnished with a _gynæcophoric_ canal, extending from
a point a little below the ventral sucker to the extremity of the tail;
this slit-like cavity being formed by the narrowing and bending inwards
of the lateral borders of the animal, the right side being more or less
completely overlapped by the left margin of the body; caudal extremity
pointed; intestine in the form of two simple blind canals. Female with a
cylindrical body measuring only 1/312″ of an inch in thickness in front
of the oral sucker; lodged in the gynæcophoric canal of the male during
the copulatory act; thickness of the body below the ventral acetabulum
being about 1/357″, and at the lower part 1/96″; surface almost smooth
throughout; intestinal canals reunited after a short separation to form
a broad, central, spirally twisted tube extending down the middle of
the body; vitelligene and germigene canals combining to form a simple
oviducal canal, which is continued into a simple uterine tube, finally
opening near the lower margin of the ventral sucker; eggs pointed at one
end, or furnished with a projecting spine near the hinder pole.

The study of the structure and formation of the contents of the ova
possesses great interest. When fully developed the eggs are oval,
measuring from 1/180″ to 1/160″ in length, with an average transverse
diameter of 1/325″. Some are a trifle larger, others smaller.
Occasionally one encounters narrow specimens, and also aberrant forms
presenting a pear-shaped outline. I have met with eggs not exceeding
1/250″ in their long diameter, and 1/500″ transversely, whose
yolk-contents had already arrived at an advanced stage of segmentation.

[Illustration: FIG. 8.--Two eggs of _Bilharzia_. _a_, With the yolk
coarsely segmented; _b_, with the yolk granulated and the spine wanting.
Original.]

The shell is transparent, of a brown colour, and free from any markings,
lines, or sculpturing. One pole of the shell is invariably narrower than
the other, and usually presents a more or less pointed extremity (fig.
8). This narrow end commonly displays a sharp, projecting, beak-like
spine, which, at its base, constantly rests upon the centre of the pole
of the shell, but occasionally it is eccentrically placed (fig. 8_a_).
In some few examples the spine is removed to a little distance from the
actual extremity of the shell; but even in these instances, so far as
my observations go, its apex always projects beyond the level of the
curved end of the pole. Now and then the spine is altogether absent
(fig. 8_b_); and when present it is, as already hinted, very unequally
developed. In size the spine ranges from a mere point, having an extreme
length of only 1/8000″, up to the comparatively large magnitude of
1/2500″ lengthways.

According to the best evidence there is no good ground for asserting the
existence of any specific differentiation between the parasites coming
from the Cape and Egypt respectively.

[Illustration: FIG. 9.--Two eggs of _Bilharzia_, with eccentrically
placed spines. That to the left shows mulberry cleavage of the yolk; the
other having lost its embryonal contents by rupture. Original.]

Taking a more extended view of the significance of these singular
chorional spines, I think we may here recognise the early efforts of
Nature, so to speak, to form or evolve a special organ, which, in
the eggs of certain other parasites, becomes capable of attaining
a relatively prodigious degree of development. To me it seems that
the little process in question is a kind of rudimentary holdfast;
and, as such, it may be reckoned as the homologue of a variety of
egg-appendages. Eleven years ago Mr Edwin Canton discovered some curious
ova attached to the conjunctiva of a turtle’s eye. I had no hesitation
in pronouncing them to be referable to some ectozoon or entozoon
belonging to one or other of the allied genera _Polystoma_, _Tristoma_,
_Octobothrium_, and _Dactylogyrus_. Now, whilst the Bilharzia ova
display only a solitary and imperfectly developed holdfast, placed at
one end of the shell, the singular eggs described by Mr Canton develop
organs of anchorage at both extremities. Parasitic ova exhibiting
analogous processes, spines, and filamentary appendages at both poles,
have been observed in various species of parasite--as, for example,
in _Monostoma verrucosum_ infesting the fox, in _Tænia cyathiformis_
infesting the swallow, in _Tænia variabilis_ of the gambet, in
_Octobothrium lanceolatum_ attached to the gills of the common herring;
and in _Polystoma appendiculata_, from the branchiæ of various marine
fishes. Eggs of parasites which, like _Bilharzia_, are furnished with a
single appendage, may likewise be seen in the ova of different species
of _Dactylogyrus_ infesting the gills of the pike. In the more strongly
pronounced developments it is easy to perceive how admirably these
outgrowths are adapted to the necessities of the different species of
parasite to which they are severally referable; and, even in the case of
_Bilharzia_, the trifling amount of anchorage furnished by a projecting
point is not absolutely thrown away. The resistance will also be greater
where the spine is situated a little on one side of the pole of the egg,
which seems to need steadying during the violent struggles of the embryo
to escape from its temporary abode.

[Illustration: FIG. 10.--Free ciliated embryo of _Bilharzia_, with
pear-shaped rudimentary organs below the head. Original.]

[Illustration: FIG. 11.--Two ciliated embryos of _Bilharzia_; showing
sarcode spherules in their interior. That to the left has recently
escaped the shell. Original.]

When any number of ova are removed from the urine and examined, it
will be found that a large proportion of them contain embryos in an
advanced stage of larval growth. The structural appearances presented
by the embryos whilst still in the eggs are remarkably uniform; since,
in all, the yolk appears to have resolved itself into a mass of rounded
sarcode-globules, one or two of these particles being conspicuously
larger than the rest (fig. 12). At this stage, except towards the
cephalic division of the larva, no tendency to differentiation is
perceptible; but some time after the embryo has escaped, one may notice
elongated masses of sarcode formed by the coalescence of the globules.
Whilst still in the egg, one end of the primitive embryonal mass becomes
gradually narrowed, cilia at the same time appearing. This part becomes
the future head, eventually acquiring the form of a cowl. Whatever form
the body of the embryo may display after extrusion from the shell,
the head retains its conical shape, the cone itself being narrowed or
widened only when the larva is subjected to abnormal conditions (fig.
14). Whilst the head is undergoing development within the shell, one,
two, or sometimes three, pyriform masses make their appearance within
the cone; and after the embryo has escaped, these structures become more
marked (fig. 10). The sarcode-globules refract light strongly; and, when
the larva is not compressed in any way, they move freely within the
somatic cavity. In well-developed embryos, whilst still in the egg, the
cilia are observed to clothe every part of the larva except the oral
papilla. This minute nipple-like projection measures about the 1/3000 of
an inch transversely, forming a very simple kind of unarmed proboscis.
When the head of the free embryo is viewed from above, the proboscis
looks like a central ring surrounded by a series of regular folds, which
radiate outwards like the spokes of a wheel. The ridges thus formed
support numerous cilia, these latter projecting at the circumferential
margin of the cephalic cone in such a way as to present the figure of
a star. Dr Harley has admirably represented this character, which is
shared by many other parasitic larvæ. Throughout the greater part of
the time, whilst the embryo is still resident within the egg, the broad
neck or base of the cephalic cone forms a fixed point of resistance by
its firm attachment to the inner wall of the shell; and this structural
union, so long as it remains intact, enables the embryo to move not
only its head and body from side to side synchronously, but also each
part independently. When the time for final escape is drawing near,
the vigorous movements of the cone-shaped head seem chiefly concerned
in loosening the membranous connection just referred to; and when, at
length, the ciliated animalcule has succeeded in overcoming this first
difficulty, it is ludicrous to witness its frantic efforts to find an
opening in the shell. While thus partially liberated, it will rush to
and fro from one pole of the egg to the other, performing a series of
summersaults, and at the same time occasionally rolling itself over
laterally. This activity becomes gradually more and more violent, until
at length its excitement is worked up into a sort of frenzy. I have
many times watched these performances, which, however, are only to be
seen within those ova whose shells, for some reason or other, refuse to
yield to the earlier and ordinary efforts of the prisoner. In all cases
where these phenomena are witnessed the eye readily detects a number of
small free globules between the embryo and the inner wall of the shell
(fig. 13). These minute particles are likewise tossed about tumultuously
during the rapid rotatory movements of the imprisoned larva. Except
as regards their size, these globules do not differ in character from
the sarcodic contents of the animalcule. They are probably superfluous
detachments from the primitive yolk-mass, but it is possible that they
may afford some aid in the final breaking up of the shell. Whilst the
embryo remains fixed its tail is usually directed towards the narrower
or spine-bearing pole of the egg, but in a few instances I have seen
this position reversed. As regards the precise mode of emerging from the
shell, and the time occupied by the larva in freeing itself, there are
several points of interest. Speaking generally, the purer the medium
into which the ova are transferred, the more rapid will be the movements
of the larvæ. To give an example of observed facts in relation to the
rapidity of development, I cite the following:--“On the 20th of August,
1870, I placed twelve eggs of _Bilharzia_ under the microscope. The
medium in which they were immersed consisted of eight parts of ordinary
drinking water to one of urine. At the expiration of seventeen minutes
the first-born made its escape. In the course of another minute two more
emerged. In twenty-six minutes the fourth, in twenty-eight the fifth, in
thirty-two the sixth, in thirty-four the seventh, in thirty-seven the
eighth, in thirty-eight the ninth, in forty the tenth, in forty-three
the eleventh, and in forty-six minutes the twelfth, respectively made
their appearance.”

[Illustration: FIG. 12.--Egg of _Bilharzia_, with contained embryo and
free sarcode globules. Original.]

[Illustration: FIG. 13.--Free ciliated embryo of _Bilharzia_, slightly
deformed, and having the pear-shaped organs largely developed. Original.]

[Illustration: FIG. 14.--Ciliated embryos of _Bilharzia_, deformed by
the application of reagents. Original.]

Now, this rapid mode of birth and emergence from the shell is very much
more striking in the case of eggs which are placed in perfectly pure
water; for, whilst the eggs are still in the urine, there appears to
be neither the power nor the inclination on the part of the embryo to
escape; but, on isolating and placing them in suitable conditions, their
behaviour is even more remarkable. In a space of less than two minutes
I have repeatedly seen the hitherto motionless embryo alter its shape
by contractions, become violently agitated, and burst out of its shell
in the condition of a free-swimming animalcule. Moreover, it is worthy
of remark that the eggs and larvæ of _Bilharzia_ soon perish in stale
urine. “On the 16th of August, 1870, I placed about a thousand eggs
in a quart of fountain-water, to which only a drachm or rather less
of urine had been added. At the expiration of forty-eight hours not a
single living embryo could be found. I subsequently ascertained that I
could not keep the embryos alive for twenty-four hours in any water in
which I had introduced the smallest trace of mucus, blood-corpuscles,
urinary crystals, or decomposing matters of any kind. All sorts of
reagents speedily killed the larvæ. Mere discoloration by carmine
solution, or by the addition of a drop of the solution of permanganate
of potash, instantly caused them to assume grotesque and unnatural
shapes (figs. 13 and 14), death sooner or later following as a result
of the disintegration and resolution of their delicate bodies into mere
sarcode-masses. Still more rapidly poisonous effects were produced by
the addition of a little sherry or alcohol. In solutions where the
amount of spirit did not exceed one part of spirit, proof strength, to
fifty parts of water the effect was the same.”

The development of the larva is equally well accomplished in distilled
water, in well-water, and in brackish water. In pure sea-water the
process goes on less satisfactorily. It was found, indeed, that the
addition of slightly saline water to ciliated embryos, which were on the
point of expiring in fresh water, had the effect of reviving them for a
time. These facts have an important practical bearing.

I have thus shown that the escape of the embryo is by no means the slow
process that Bilharz has described. Almost invariably the shell bursts
by a longitudinal slit extending over fully two thirds of its long
diameter, the first point of rupture being commonly situated midway
between the spine and the centre of the shell. In normal births, so
to speak, the head of the animalcule emerges first; but occasionally
the animal escapes sideways, and I have even seen the embryo extricate
itself tail foremost. Not unfrequently it has a difficulty in detaching
itself from the shell, in which case the egg is whirled round and
round by the half-freed prisoner (fig. 15). The lodgment of the spine,
however, against any foreign substance affords the necessary leverage
for ensuring escape.

The larva never displays its proper elongated, spindle-shaped, or
cylindro-conical figure, until some short time after its escape from the
shell; and, as a consequence of this, its powers of locomotion are less
marked at first than they are subsequently. At the time of extrusion
the larvæ are commonly more or less hour-glass shaped (fig. 11); this
particular form being sometimes retained for many minutes or even for
an hour. Usually the larvæ have a tendency to acquire their normal
shape immediately after quitting the shell; the oval, pear-shaped, and
variously contracted forms gradually merging into the characteristic
cone-shaped animalcule (fig. 10). In their fully developed condition,
they exhibit the most lively movements; and to witness several hundreds
of them rushing about with unceasing activity is a curious sight. The
phenomenon, moreover, loses none of its interest from the consideration
that only a few hours, or it may have been minutes, previously, these
now actively gyrating animalcules were lodged _in ovo_ within the
blood-vessels of their human host. From persons who are infested,
myriads of these eggs of _Bilharzia_ daily make their escape during
the act of micturition; and, when this act is accomplished by the
host out-of-doors, it is easy to perceive how readily the ova may be
subjected to conditions favorable to the development of larvæ. The
direct passage of the urine into any considerable receptacle of natural
or fresh water would in a few minutes ensure the hatching of all the
eggs; and in the absence of any such direct aid to development, the
accidental occurrence of a shower of rain would, in all localities
where the _Bilharzia_ disease is endemic, readily transfer the ova into
ditches, ponds, rivers, lakes, and ultimately, perhaps, even into the
sea itself.

[Illustration: FIG. 15.--Egg of _Bilharzia_, with the shell adhering to
the escaped ciliated embryo. Original.]

[Illustration: FIG. 16.--Ciliated embryo of _Bilharzia_ in the act of
dying from the escape of the sarcodic contents. Original.]

The behaviour of the embryo under the action of reagents of various
kinds is remarkable. Thus, when on the 5th of Sept., 1870, I placed
some ova in brackish water, of the strength of two parts of fresh
water to one of pure sea-water, their contents were readily developed,
though the escaping embryos did not swim vigorously. When again I
placed some other eggs in pure sea-water, their contained embryos
became instantly transfixed, the vibratile cilia of the head being
rigid and motionless. At first I naturally concluded that the embryos
were killed outright; but, to my great surprise, the shock passed away
in about half an hour, when they revived and were soon afterwards
hatched. One of the larvæ thus set free carried off several of the loose
intra-chorional globules which had, during the period of transfixion,
become firmly adherent to the ends of the caudal cilia. Here I may
remark upon a decided difference observable between the cilia of the
head and body respectively. The former are at all times vibratile,
active, and conspicuous, whilst the latter are more delicate, capable
of comparatively little motion, and partaking more of the character
of fine setæ. In length their general measurement varies from 1/2500″
to 1/2000″. The action of pure sea-water on the free animalcules,
previously immersed in fresh or brackish water, was equally striking.
All, without exception, immediately became paralysed and almost
motionless; nevertheless, on again adding fresh water, several entirely
recovered. It is worthy of notice that in these cases the cephalic
cilia furnished the first indications of returning viability. I was
particularly struck with the behaviour of one embryo, which, under
the stimulus of the sudden shock, retracted its cone-shaped head
almost entirely within the general cavity of the body (fig. 14, lower
specimen). In their moribund condition, whatever shape the embryo
retained, the sarcodic contents gradually faded away; the outline of
the creature, however, becoming more marked (fig. 16). Usually the body
of the animalcule became elongated whilst expiring in sea-water. Under
other circumstances the embryo frequently bursts; the sarcodic contents
escaping in the form of amœba-like bodies and the cilia retaining their
powers of movement long after all traces of the sarcode have disappeared.

[Illustration: FIG. 17.--Ciliated embryo of _Fasciola hepatica_, showing
the so-called eye-spot. After Leuckart.]

The larvæ of _Bilharzia_ closely resemble those of _Fasciola hepatica_,
which latter may be appropriately noticed in this place. The ciliated
embryo of the common liver fluke has the form of a long cone inverted;
the anterior end or head being flatly convex. In the centre is a short
proboscis-like papilla destitute of cilia (fig. 17). The general
covering of cilia rests on a well-defined granular epidermis; this
latter being succeeded by a dense peripheral layer of large nucleated
cells, each of them measuring about 1/2500″ in diameter. The epidermis
measures 1/6250″ in thickness. In the central mass of parenchyma no
internal organs are recognisable, but Leuckart observed indications of a
canal which he thought might open at the tail, though the opening itself
was not actually visible.

As long as the ciliated covering remains intact the embryo, like other
animalcules, displays great activity, whirling round and round on
its own axis, and also describing gyrations and circles of different
degrees of range in the water, the latter movements being accomplished
by bending the body upon itself to a greater or lesser curvature. The
embryos of _Bilharzia_ and other infusoria exhibit the same behaviour,
and, as Leuckart observes, when these embryos knock against any
obstruction, they pause after the blow, as if to consider the nature
of the substance they have touched. As in the case of fluke embryos
generally, the ciliated covering eventually falls off and the embryo
reassumes a more or less oval figure, at the same time changing its
swimming mode of progression for the less dignified method of creeping.
In the free ciliated condition the embryo of the common liver-fluke
measures, according to Leuckart, 1/190″ in length, the anterior broad
end being 1/500″. The cilia have a longitudinal measurement of 1/1388″.

According to the observations of Dr Willemoes-Suhm, the cilia of the
embryos of the _Distoma megastoma_ are limited to the anterior pole of
the body. This is also the arrangement, as Leuckart first pointed out,
in _Distoma lanceolatum_ (fig. 18). On the other hand, Pagenstecher has
shown that the embryos of _Distoma cygnoides_ and _Amphistoma_
(_Diplodiscus_) _subclavatum_ are ciliated all over, an observation
which, as regards the latter species, has been confirmed by Wagener and
others. Dr Pagenstecher’s original statement to the effect that
“intrachorional germs of trematodes offer no distinctive characters,”
must, therefore, in the present state of our knowledge, be accepted as a
general conclusion admitting of many exceptions. In the early stages of
development the embryo of _Distoma lanceolatum_ occupies the centre of
the egg, and according to Leuckart has its conical head invariably
directed towards the upper pole of the shell, or, in other words, to
that end of the egg which is furnished with a lid-like operculum.
Leuckart describes the embryo itself as “finely granular and armed at
the tip with a dagger-like spine, which, with the simultaneous
displacement of the adjacent granular mass, can be pushed forward and
drawn back again.” Besides this so-called cephalic granular mass, there
are within the embryonic body two other granular masses widely separated
from each other, but occupying the posterior half of the embryo. These
Leuckart supposes to be the rudiments of a future brood, to be developed
at the time when the free embryo shall have lost its ciliated swimming
apparatus, shall have bored its way by means of the cephalic spine into
the tissues of a mollusk, and shall have become metamorphosed into a
sac-like larva (Nurse, Sporocyst, or Redia, as the case may be).
Whatever be the full significance of these internal developments, we
have at least satisfactory evidence that the complete and free embryo is
a globe-shaped animalcule, having the anterior third or cephalic end of
the body covered with cilia, and armed with a central boring spine. In
consequence of this limitation of the ciliated covering, its swimming
movements are less vivacious than those of the embryo of _Fasciola
hepatica_; it will, therefore, probably take up its residence in a less
active host than that chosen by the embryo of Fasciola, selecting one of
those mollusks which either move slowly or are prone to keep at the
bottom of the water. The mature eggs have a length of 1/625 to 1/555 of
an inch, and a breadth of 1/833″. The long diameter of the free embryo
varies from 1/990″ to 1/833″, the transverse diameter being 1/1562″.
Whilst the embryos were still in the egg Leuckart could see no ciliary
motion. With most observers, both the ciliary apparatus and the boring
spine appear at this stage to have altogether escaped observation.

[Illustration: FIG. 18.--Ciliated embryo of _Distoma lanceolatum_. After
Leuckart.]

As regards the intimate structure of the ciliated embryo of _Bilharzia
hæmatobia_, I have further to observe that, shortly after its extrusion
from the shell, the hitherto loose, globular sarcode particles
coalesce. This is apparently a preliminary step towards the subsequent
differentiation process. Respecting the pedunculated blind sacs formed
within the head, I think that we must regard the largest one as
representing the stomach of the larva in its future cercarian stage.
Under the 1/12″ objective I distinctly recognised, in the cavity of the
central blind sac, numerous highly refracting granules, the diameter of
which averaged not more than 1/12000″. The rudimentary stomach is often
traceable whilst the larva is still within the egg. It measures about
1/500″ in length, including the peduncle, and 1/14000″ in breadth. The
width of the narrow stalk does not exceed 1/9000″. The other two-stalked
bodies appeared to have the character of _lemnisci_. They were
occasionally well seen whilst the embryo was still within the egg. As
regards the integument, it is easy to recognise two layers. In careful
adjustments of the focus the inner wall of the transparent dermis
presents a beaded appearance. These minute and regular markings do not
undergo alteration during the contractions of the body of the larva.

[Illustration: FIG. 19.--Outline representation of a ciliated embryo
of _Bilharzia_, showing the arrangement of the water vessels and the
vacuoles. Original.]

A highly developed water-vascular system exists in these little
animalcules. On many occasions I saw traces of this set of vessels,
and in several instances I obtained a most satisfactory view of the
entire series of branches. Anxious to receive confirmation of my
discovery, I demonstrated the existence of these vessels to a skilled
microscopist--the late Mr J. G. Pilcher, of H. M. Army. In the briefest
terms it may be said that the water-vascular system of _Bilharzia_,
in the larval condition, consists of two main stems, which pursue a
tortuous passage from head to tail, and which, in the course of their
windings, give off several anastomosing branches (fig. 19). As also
obtains in the corresponding larvæ of _Diplodiscus subclavatus_, there
is no excretory outlet visible at the tail.

Encouraged by the experiences and determinations of Pagenstecher,
Filippi, Wagener, Leuckart, and others, I sought for the intermediate
hosts amongst fresh-water mollusks and small crustacea. Failing of
success in these, it occurred to me that the larvæ of _Bilharzia_ might
normally reside in fluviatile or even in marine fishes. This latter idea
seems also to have struck Dr Aitken. In an appendix to his ‘Report to
the Army Medical Department for 1868,’ dated from Netley, Nov., 1869,
he gives a figure of a nurse-form, which he terms a cercaria, from the
tail of a haddock--suggesting for _Bilharzia_ some genetic relation. Dr
Aitken also extends his views in reference to certain larval trematodes
alleged to have been found in the so-called Delhi boils and Lahore
sores. These parasitic forms have, however, been shown by Dr Joseph
Fleming to be nothing more than altered hair-bulbs (‘Army Med. Reports,’
1868-69).

In regard to the flukes from the haddock, I have satisfied myself that
these immature trematodes from the nerves of the cod-tribe can have no
genetic relation with _Bilharzia_; and I think it due to Dr Maddox to
say that I accept his conclusion respecting them. In his paper (‘Micros.
Trans.,’ vol. xv, 1867, p. 87) he offers strong proof that the so-called
_Distoma neuronaii Monroii_ of the haddock (_Morrhua æglefinus_) is
the juvenile condition of _Gasterostoma gracilescens_ of the angler
(_Lophius piscatorius_).

I am sorry to have to state that all my experiments proved negative. I
tried to induce the ciliated embryos to enter the bodies of a variety
of animals, such as Gammari, Dipterous larvæ, Entomostraca, Lymnæi,
Paludinæ, different species of Planorbis, and other mollusks; but
neither in these, nor in Sticklebacks, Roach, Gudgeon, or Carp, did they
seem inclined to take up their abode.

The very peculiar and formidable helminthiasis produced by this
parasite has been thoroughly investigated by Griesinger and Bilharz,
and it has been fully described in the standard works of Küchenmeister
and Leuckart. My own case from Natal also supplied many interesting
clinical facts which were published in my ‘Lectures on Helminthology,’
quoted below. The comparative prevalence of this disorder in Egypt is
well established. Symptomatically, its principal feature consists in a
general disturbance of the uropoietic functions. Diarrhœa and hæmaturia
occur in advanced stages of the complaint, being also frequently
associated with the so-called Egyptian chlorosis, colicky pains, anæmia,
and great prostration of the vital powers. The true source of the
disorder, however, is easily overlooked unless a careful microscopic
examination be made of the urine and other evacuations. If blood be
mixed with these, and there also be a large escape of mucus, a minute
inspection of the excreta will scarcely fail to reveal the presence of
the characteristic ova of _Bilharzia_. Besides the increase of mucus
secretion, there may even be an escape of purulent matter, showing that
the disorder has far advanced. The patient’s constitution eventually
becomes undermined; pneumonia often sets in, and death finally ensues.
On making post-mortem examinations the following pathological facts come
to light. In cases where the disease has not advanced very far, minute
patches of blood-extravasation present themselves at the mucous surface
of the bladder, but in more strongly pronounced cases the patches
are larger or even confluent. In some instances there are villous
or fungus-like thickenings, ulceration and separation of portions of
the mucous membrane, with varying degrees of coloration, according to
the amount of the extravasation, which becomes converted into grey,
rusty-brown, or black pigment deposits. A gritty or sandy deposit is
often superimposed, consisting of ordinary lithic-acid grains mixed
with eggs and egg-shells. Eggs are readily detected in the urine, these
having escaped from the ruptured vesical vessels. The lining membranes
of the ureters and renal cavities are also more or less affected; the
kidneys being frequently enlarged and congested. It must, however, be
borne in mind that in all these organs the true seat of the disorder is
the blood, which forms the proper habitat of the _Bilharzia_; and this
being the case, the worms as well as their escaped eggs may be found
in any of the vessels supplying the diseased organs. In one instance,
quoted by Leuckart, Griesinger found a number of empty eggs in the left
ventricle of the heart, and from this circumstance it was supposed that
they might be carried into various important organs, or even plug up
the larger vessels. As before stated, however, the parasites are more
particularly prevalent in the vessels of the bladder, mesentery, and
portal system. The effects upon the intestinal mucous membrane are, in
most respects, similar to those occurring in the urinary organs. Blood
extravasations, with thickening, exudation, ulceration, and fungoid
projections, appear in and upon the intestinal mucous and submucous
tissues; these appearances, of course, being more or less strongly
marked according to the degree of infection.

In regard to the treatment of the helminthiasis, I am precluded from
entering into details here; nevertheless, I am glad to perceive that
the principles which I long ago enunciated have received approval both
at home and abroad. As stated in my ‘Lectures’ our object should be not
to interfere with, but to promote nature’s curative efforts. If I read
the pathological facts correctly, she seeks to bring about this result
by erecting artificial barriers which serve to moderate the bleeding.
In this way, under ordinary circumstances, the life of the bearer is
sustained, or held in the balance until the parasites either perish or
cease to be capable of causing active disease. Depend upon it, this
is the principle which should guide physicians in their treatment of
the Bilharzia disorder. If the adult parasite were merely attached
to the lining membrane of the bladder, then powerful diuretics and
medicated injections would probably prove serviceable; but since the
entozoa reside in the blood we must be careful not to increase the
patient’s troubles. In the case of intestinal worms the most powerful
parasiticides may be prescribed without let or hindrance; but that drug
must be a truly subtle worm-poison which, when taken into the system,
shall kill the blood-flukes without exerting any injurious effects upon
the parasite bearer.

When, in 1872, I published my lectures on helminthology, I remarked
that it was not improbable that, ere long, many more cases of Bilharzia
disease would be brought to light. What has been added in this respect
is chiefly due to the researches of Sonsino, but a case of some interest
has been recorded comparatively recently by Dr W. K. Hatch, stationed
at Bombay. From the particulars furnished it seems evident that the
victim, an English gentleman, contracted the disease by drinking water,
either in Arabia or in Egypt, in which latter country, however, he had
only sojourned fifteen days. From the patient’s statements it appears
that, hæmaturia is frequent amongst the Arabs. Incidentally, Dr Hatch
mentions that Dr Vandyke Carter had informed him that, so early as the
year 1862, he (Dr Carter) had detected the embryos of Bilharzia in the
urine of an African boy admitted to the Jamsetjee Jejeebhoy Hospital.
The treatment employed by Dr Hatch was that recommended by Dr Harley in
his well-known memoir. Having myself energetically opposed Dr Harley’s
views on pathological grounds, I am not surprised to see it stated
that Dr Harley’s method of treatment effected “no diminution in the
number of the parasites.” As I said in my lectures (now out of print)
it is evident that “nature” in view of moderating the hæmaturia--by the
formation of plugs at the ulcerated points of the mucous surface--sets
up the artificial barriers above referred to; therefore if you
catheterise and employ medicated injections you do more harm than good.
As to the administration of belladonna internally, in view of retarding
development, or of destroying the parasite, no good can be expected
from this source. I certainly obtained better results with buchu and
bearberry (_Arctostaphylos_).

In the matter of sanitation it is quite evident, from the foregoing
data, that the danger of infection cannot arise from the drinking of
impure water, as ordinarily understood. The embryonal larvæ would be
killed by an admixture of sewage. It is obvious that infection can
only occur from swallowing free cercariæ or freshwater mollusks which
contain the higher larval forms in their encysted or pupa condition.
Slow running streams or stagnant pools with sedgy banks are eminently
favorable to the existence and multiplication of intermediary bearers,
and consequently their waters are dangerous if employed for drinking
purposes.

BIBLIOGRAPHY (No. 12).--_Bilharz_, in Siebold and Köll., ‘Zeitsch. für
wissensch. Zool.,’ iv, 1851.--_Idem_, ‘Wiener medic. Wochenschrift,’
1856.--_Cobbold, T. S._, “On some new forms of Entozoa (_Bilharzia
magna_),” ‘Linn. Trans.,’ vol. xxii, p. 364, 1859.--_Idem_, “Synopsis
of the Distomidæ,” in ‘Proceed. Linn. Soc.,’ vol. v, Zool. Div., p.
31, 1860.--_Idem_, “Remarks on Dr J. Harley’s _Distoma capense_,” in
‘Lancet,’ also in the ‘Veterinarian,’ and in ‘Intell. Observer’ for
Feb. and March, 1864.--_Idem_, “Entozoa,” l. c., p. 197, 1864.--_Idem_,
“On Blood Worms,” Lecture xx in ‘Worms,’ l. c., p. 145 et seq., 1872;
Tommasi’s edit., Vermi, p. 141, 1873.--_Idem_, “On the Embryos of
_Bilharzia_,” ‘Brit. Assoc. Rep.,’ 1864.--_Idem_, “On the Development
of _Bilharzia hæmatobia_, together with Remarks on the Ova of another
Urinary Parasite occurring in a case of Hæmaturia from Natal,” ‘Brit.
Med. Journ.,’ July, 1872; repr. in the ‘Veterinarian,’ 1872.--_Idem_,
‘New Entozootic Malady, &c.’ (brochure), London, 1865.--_Idem_,
“Helminthes,” in Gunther’s ‘Record of Zool. Literature,’ p. 617,
1865.--_Idem_, “Entozoa in relation to Public Health and the Sewage
Question,” Rep. of the Proceed. of the Metrop. Assoc. of Officers
of Health, in ‘Med. Times and Gazette,’ Jan., 1871, repr. in the
‘Veterinarian,’ p. 359, 1871.--_Idem_, “Verification of recent
Hæmatozoal Discoveries in Australia and Egypt,” ‘Brit. Med. Journ.,’
June, 1876.--_Idem_, “On Sewage and Parasites, especially in relation
to the Dispersion and Vitality of the Germs of Entozoa,” rep. in
‘Med. Times and Gaz.’ for Feb., and the ‘Veterinarian’ for May,
1871.--_Davaine, C._, l. c., ‘Synops,’ and p. 312, 1860.--_Diesing,
C. M._, ‘Revis. d. Myzelmith,’ Vienna, 1858.--_Griesinger_, “Klin.
und Anat. Beobachtungen über die Krankheiten von Egypten,” in ‘Arch.
für physiol. Heilkunde,’ 1856.--_Idem_, ‘Gesammelte Abhandlungen,’
Berlin, 1872.--_Idem_, ‘Arch. d. Heilk.,’ 1866.--_Harley, J._, ‘On
the Hæmaturia of the Cape of Good Hope, produced by a Distoma,’ rep.
in ‘Lancet,’ and ‘Med. Times and Gaz.,’ Feb., 1864; also in Ranking’s
‘Abstract,’ p. 173, 1864, and fully in ‘Medico-Chirurg. Trans.,’
1865.--_Idem_, “On the Endemic Hæmaturia of the South Eastern Coast
of Africa,” ‘Med.-Chir. Trans.,’ vol. liv, 1871.--_Idem_, in Hooper’s
‘Vade Mecum,’ 1869.--_Hatch, W. K._, “Case of _Bilharzia hæmatobia_,” in
‘British Medical Journal,’ Dec. 14, 1878, p. 875.--_Küchenmeister, F._,
‘Parasiten,’ 1855; Eng. edit., p. 277, 1857.--_Leuckart, R._, l. c., s.
617, 1863.--_Sonsino, P._, “Richerche intorno alla Bilharzia hæmatobia
in relazione colla Ematuria Endemica dell’ Egitto e nota intorno
un Nematoideo trovato nel Sangue Umano,” ‘Estr. dal Rend., del. R.
Accad.,’ 1874.--_Idem_, ‘Della Bilharzia hæmatobia e delle alterazione
Anatomo-patologiche che induce nell’ Organismo Umano, loro importanza
come Fattori della Morbilità e Mortalità in Egitto, con cenno sopra
una Larva d’Insetto Parassita dell’ Uomo. Estratto dall’ Imparziale,’
Firenze, 1876.--_Idem_, ‘Sugli ematozoi come contributo alla Fauna
Entozooca Egiziana,’ Cairo, 1877.--_Idem_, “La Bilharzia hæmatobia, et
son rôle Pathologique en Egypte,” ‘Arch. Gén. de Médicine,’ for June, p.
650, 1876.--_Idem_, “Intorno ad un nuovo Parassita del bue (_Bilharzia
bovis_),” ‘Estr. dal Rend. del. R. Accad. di Napoli,’ 1876.--_Weinland,
D. F._, l. c., p. 67, 1858.



SECTION II.--CESTODA (Tapeworms).


_Tænia mediocanellata_, Küchenmeister.--This cestode is frequently
spoken of as the unarmed or beef tapeworm. In general appearance it is
very similar to the armed form. It is, however, a larger and broader
animal, being at the same time rather stouter. It varies usually
from fifteen to twenty-three feet in length, but specimens have been
described as attaining thirty feet. It is called the unarmed tapeworm
in consequence of the absence of any coronet of hooks on the head;
and consequently, also, from there being no prominent rostellum or
proboscis. The place of the last-named structure, however, is supplied
by a small rudimentary disk, which I have seen protruded on pressure
(fig. 20). Usually this disk forms a more or less conspicuous cup-shaped
circular depression, which has been compared to and described as a fifth
sucker. That it is not, in any structural sense, comparable to the true
suckers, I have had abundant opportunity of ascertaining; nevertheless,
I do not doubt that it is to a slight extent capable of being used by
the parasite as a supernumerary holdfast. The anchorage thus secured,
however, is by no means equal to that obtained by the armed species.
This explains the comparative difficulty we find in procuring a specimen
of the armed tapeworm with the head attached.

[Illustration: FIG. 20.--Head of _Tænia mediocanellata_. Showing the
calcareous corpuscles, suckers, rudimentary proboscis, and water
vessels. Highly magnified. Original.]

The establishment of this species as distinct from _T. solium_ is due
to Küchenmeister; but it is curious to observe how accurately this
determination was foreshadowed by the shrewd naturalist and theologian,
J. A. E. Goeze, who clearly indicated two forms of the common tapeworm,
remarking (l. c., Bibl. No. 1, s. 278):--“Die erste ist die bekannte
grosse, mit langen dicken und gemästeten Gliedern, die ich _Tænia
cucurbitina, grandis, saginata_, nennen will.” The same author (s.
245) pointed out the resemblance subsisting between the tapeworm of
the cat (_T. crassicollis_) and the vesicles (“Krystallblasen”) and
their contained “erbsförmige Blasen” (_Cysticercus fasciolaris_) of the
mouse. Thus the celebrated pastor of St Blasius, in Quedlinberg, almost
contemporaneously with Pallas, early arrived at the conclusion that the
hydatid-measle was a kind of tapeworm.

[Illustration: FIG. 21.--Free proglottides of _Tænia mediocanellata_.
After Leuckart.]

Respecting the organisation of this worm I may observe that the mature
joints have a more complicated uterine organ than obtains in _Tænia
solium_, presenting nearly double the number of lateral branches.
They are more closely packed, running outwardly in an almost parallel
manner. The first sexually mature proglottis occurs at about the 450th
joint, but whereas, in the pork tapeworm, only some 200 subsequent
segments share this perfect character in the beef tapeworm, according
to Leuckart, as many as 360 or even 400 mature joint may be present.
The joints are very liable to form monstrosities; these abnormalities
sometimes affecting the reproductive organs, which become doubled
or even trebled. In the Hunterian collection there is a proglottid
showing twenty-two sexual orifices. Dr Cullingworth, of Manchester, has
described a specimen in which the joints are curiously tripartite.

As already hinted the true source of this parasite has been proved by
experiment; the first successful worm-feeding having been accomplished
by Leuckart. Mosler’s, and subsequently my own feeding experiments,
immediately followed. Other successful experiments with this species
have been conducted by Zurn, Probstmayer, St Cyr, Perroncito, Masse and
Pourquier, and Zenker. As will be again mentioned below Dr Oliver, R.A.,
whilst stationed at Jullundur, successfully reared the adult tapeworm in
a Mohammedan groom and in a Hindoo boy. It will also be seen that Prof.
Perroncito reared the worm in a student in fifty-four days. In my own
experiments on animals I was assisted by Professor Simonds. The feeding
materials were tapeworms expelled from my own patients. We obtained the
following interesting results:

_Exp. 1._--A calf. First feeding, Dec. 21st, 1864. Marked symptoms.
Slaughtered April 3rd, 1865. Result positive.

_Exp. 2._--A calf. First feeding, April 13th, 1865. Second, third, and
fourth feedings in May and June. No symptoms. Died on Sept. 3rd, 1865,
after thirty-six hours’ illness with “cattle plague.” Result stated to
have been negative as far as the muscles were concerned. Viscera not
examined.

_Exp. 3._--A Dutch heifer. First feeding, March 3rd, 1865. Three
subsequent feedings. Symptoms only slight. Slaughtered April 4th, 1866.
Result positive. Measles especially numerous in the diaphragm, but all
had undergone calcareous degeneration.

_Exp. 4._--A calf. Fed May 27th, 1872, with ripe proglottides. Marked
symptoms set in on June 7th, which began to abate on the 12th, and had
nearly disappeared by the 20th of the same month. The record of the
post-mortem result has been lost; but the animal was infected.

_Exp. 5._--A calf, which had been made the subject of a “glanders
experiment.” First fed on Oct. 17th, 1872, and thrice in the following
year, Jan. 1st and 11th, and March 8th. No symptoms having appeared the
animal was kept for six or eight months after the last feeding. Seeming
to be free from disease of any kind, it was sold as a sound heifer.

_Exp. 6._--A young heifer calf, of six months. Fed Oct. 18th, 1873,
with the mature proglottides of a large beef tapeworm. No symptoms.
Slaughtered several months afterwards. Result stated to have been
negative. Unfortunately I was not present at the autopsy.

_Exp. 7._--A young heifer. First fed May 19th, 1874, with the joints of
a tapeworm, and again on June 12th. No apparent ill effects resulted,
but the animal died in October. At the post-mortem examination, made
by Prof. Simonds, no parasites were observed. Subsequently I found
calcareous specks in the liver which proved to be degenerated measles.

_Exp. 8._--A calf. Fed on or about March 24th, 1875, with sexually
mature joints. The calf was put to and remained with a foster mother
until it died from disease of the larynx on the 15th of the following
July. The animal was ill-treated by its foster parent, and at the
post-mortem I observed a large intercostal cicatrix, evidently
the result of injury. In this case I devoted several hours to the
exploration of the muscles and viscera. Not a trace of the _Cysticercus
bovis_ could be found in the muscles or connective tissues, but the
liver contained scores of perfectly developed measles, besides hundreds
of others in various stages of calcareous degeneration. On comparing
some of the latter with those I had obtained from the preceding
experiment the pathological appearances were at once seen to be
identical. It was easy to find and pick out the measles in their cysts
from the naturally friable liver. I also detected four Cysticerci in the
lungs, two of which had degenerated. Microscopic examination confirmed
my interpretation of the naked-eye appearances.

[Illustration: FIG. 22.--Section of the heart of a calf infested by
cestode larvæ. After Mosler.]

Fragmentary as the above data are, they serve to show that we have
hitherto been too hasty in concluding that beef and veal measles reside
only in the voluntary and striated muscles of their hosts. The facts
here recorded prove that the liver of a calf may be extensively invaded
by cysticerci, and yet the animal will exhibit no sign of constitutional
disturbance. The cestode tuberculosis may come and go without any
diagnostic symptom, whilst a few months suffice for the natural death
and decay of the parasite by calcareous degeneration. Thus it becomes
extremely probable that many experiments hitherto regarded as negative
in their results have really been positive; the pathological evidences
having been either misinterpreted or altogether overlooked. Every
pathologist is familiar with gritty particles in the various viscera
of man and animals, but few are probably aware how constantly these
are dead and degenerated Cysticerci. The gritty particle itself may be
reduced to the merest point, no larger than the _receptaculum capitis_
of the Cysticercus itself, and in course of time it will disappear
entirely. Practically it is satisfactory to have experimental evidence
of the fact that cattle, as well as other animals, however extensively
measled they may have been, can become thoroughly cleansed of the
disorder by nature herself. It is only necessary that the diseased
animals be separated from infectious influences.

Although the beef measle has never yet been found in man, I have for
convenience sake introduced the facts of larval parasitism in this
place. The sanitary bearings of this subject are far too important to
be dismissed in a summary manner. I have shown that the prevalence or
rarity of the beef tapeworm in man is strictly dependent upon the habits
of the people; this same cause operating to produce healthy or diseased
meat-food, according to the degree of civilisation. In this connection
the oft-quoted statements of Kaschin respecting the prevalence of
tapeworms among the Burätes, and the well-known frequency of this
entozoon in Abyssinia, need only be alluded to.

When discussing the food question in my ‘Manual,’ I freely availed
myself of facts privately communicated by Dr. Joseph Fleming, and I
especially referred to the published labours of Lewis, Hewlett, Veale,
and other observers stationed in India. Beef measles are extremely
common in the cattle of the north-west provinces of India, so much
so that severe restrictions have been imposed upon the consumption
of ration beef. The presence of a few measles in the flesh of cattle
has been deemed a sufficient excuse for condemning and burying entire
carcases. The measle is easily distinguished from that of mutton and
pork by the fact that its head is not furnished with hooks, whilst in
the place of a rostellum there is a small, centrally placed, retractile
disk, which assumes the appearance of a supplementary sucker as in the
adult worm. The four true suckers are also comparatively large. The
measle usually varies in size from the fourth to the half of an inch in
length, but my cabinet contains a specimen nearly an inch long. This
was contributed by Dr J. Fleming, who mentions having seen a measle
which, when unrolled, measured nearly an inch and a half in length.
Although thousands of these bladder worms must exist in the cattle of
England, up to the present time not a single instance has been recorded
of the occurrence of these cystic parasites in the United Kingdom,
except in our experimental animals. Notwithstanding my inquiries, I
have not yet found a butcher, flesher, meat-inspector, or veterinarian,
who has encountered this parasite in any animal slaughtered for the
market. Several butchers have denied their occurrence in meat sold by
themselves. Even so late as June, 1874, the presence of measles in the
flesh of cattle was denied before an assembly of French _savans_; yet
for many years past I have constantly exhibited measly beef and veal in
the lecture room of the Royal Veterinary College. (See the discussion of
the Société de Thérapeutique, recorded in the ‘Bullétin Gén. de Thér.’
for June 30th, 1874, and also the ‘Jour. de Thér.,’ No. 14, for July,
p. 556, where, however, special remarks on this head have been omitted;
see also the ‘Lond. Med. Record’ for July 29th, 1874, p. 472, and the
‘Lancet’ for Dec., 1874, p. 794.) Quite in contrast with the statements
referred to are those of recent Italian observers.

Some few years back Professor G. Pellizzari communicated to the
Medico-Physical Academy, at Florence, the results of a series of
experiments conducted by himself, with the assistance of Dr Tommasi, in
regard to the temperature necessary for the destruction of cysticerci in
measled meat. An account of these experiments is published in Tommasi’s
edition of my ‘Manual.’ The researches were made in relation to certain
sanitary measures effected by the Municipal Commission of Florence,
the express object of these measures being to prevent the injurious
distribution of measly meat, especially that of swine. Signor Bosi, the
superintendent of the public slaughterhouses, granted every facility in
his power. In a previously published memoir by Professor E. Perroncito
it was stated that measly meat (_panicatura degli animali_) required
a higher temperature than that of boiling point for the destruction
of the bladder worms in question. In this opinion Signor Bosi shared.
According to the original memoir of Perroncito we are told that “about
twenty specimens of Cysticerci were collected by the author, and
placed in boiling water. After twenty minutes’ boiling, not one of the
parasites appeared to suffer. The head continued to be drawn into the
body, and when the Cysticerci had their heads drawn out one by one
they still appeared to possess all the elasticity of living bladder
worms, displaying those movements of extension which are proper to
parasites not yet dead. The hooks were observed regularly disposed on
the proboscis, where they formed a double crown, the suckers remaining
intact.” Perroncito remarked, however, that the Cysticerci showed a
coloring tendency towards brown, and he added that “with the aid of
two needles it became easy to lacerate the body of the Cysticercus,
which appeared to be swollen, and possessed of diminished cohesion of
its parts.” It was evident to all eyes, observed Professor Pellizzari,
that these statements involved clear contradictions. Yet again, at page
28 of the memoir, Professor Perroncito wrote:--“During the past winter
I introduced some little slices (_fettuccie_) of muscle-flesh (8 to
10 millimètres in thickness), infested with Cysticerci into a vessel
(_cassolina_) containing fat at the temperature of 190 to 200° Cent.
(374 to 400° Fahr.). At the expiration of ten or fifteen minutes the
slices of meat were fried, and the Cysticerci lying at the surface had
acquired a light brownish colour, as if they were roasted. By breaking
up the slices one could still see the small reddish muscular bundles,
whilst the Cysticerci in the middle remained entire and well preserved.
Their heads displayed the hooks and suckers regularly distributed.” It
is certainly singular, as Pellizzari observes, that these Cysticerci,
having been thoroughly fried and roasted, should still remain alive and
in their normal state; but the ultimate conclusion at which Perroncito
arrived was still more startling, and one which, if it were true, would
not fail to create a considerable stir among our officers of health. On
reviewing the whole matter Perroncito says:--“It appears to me that the
melted fat alone of hogs (_maiali grandinosi_) should be utilised, and I
am pleased to reckon the illustrious Gerlach and all other distinguished
practitioners to be of the same opinion. Permit me, therefore, being
well satisfied also with the results of many other experiments, once
more to advance the conclusion that, if it is not certain that the
Cysticerci die at from 80 to 100° Centigrade (176 to 212° Fahr.), we are
quite sure that they dry up and become completely mummified at 125, 130,
and 150° Cent. (257, 268, and 302° Fahr.), temperatures which we could
easily produce by means of a properly constructed apparatus.”

After remarking upon the serious nature of the conclusion which
Perroncito sought to establish, Professor Pellizzari makes further use
of quotations which bear upon the question as to whether the quality of
the vessels in which the fat of diseased hogs is melted down may not
largely affect the degree of high temperature sought to be obtained (in
view of a perfect destruction of the Cysticerci). Perroncito repeatedly
witnessed the operations of pork-butchers; and when portions of meat
were introduced, with water, into the cauldrons, he always saw that the
temperature “was maintained between 97° and 98° Centigrade.” However,
this part of the question may be dismissed in a very few words, since
Perroncito himself finally allows that “the different composition of the
vessels cannot elevate the temperature of the fat by many degrees.”

With the praiseworthy intention of either verifying or refuting these
conclusions, Pellizzari, with the approval of Bosi and with the
assistance of Tommasi, instituted a fresh series of experiments at a
private laboratory. The details of these experiments are exceedingly
interesting; but as their record occupies several pages of Tommasi’s
appendix already referred to, I must content myself with a general
statement of the results obtained. Professor Pellizzari found that
Cysticerci, so far from requiring a temperature of upwards of 100°
Centigrade for their destruction, die at a temperature of 60° Centigrade
(140° Fahr.). He had, it appears, previously taken the initiative in
recommending certain measures to the Florentine municipality, in view of
protecting the public health, and he had now the satisfaction of more
than confirming the wisdom of these sanitary precautions. In excessively
measled animals the fat is removed and boiled in suitable cauldrons, and
has potash mixed with it to render it useful for industrial purposes.
By the various measures adopted the entire animal is utilised, and with
proper precaution there seems little chance for the measles to arrive at
the tænioid or sexually mature condition.

In the next part of his communication Pellizzari touches upon the
question of measles in beef, referring especially to the experimental
labours of Leuckart and myself. Finding additional support from our
views Pellizzari declared the propositions of Dr Perroncito as of no
value whatever. “But how is it,” he adds, “that notwithstanding that
so low a temperature suffices to kill these cysticerci, yet cases of
Tænia are continually occurring?” The answer to this question will
appear in the sequel; but meanwhile it will be as well to refer to the
recent _brochure_ by Dr Giacomini. This author appears to have had no
opportunity of perusing Pellizzari’s communication already cited, and
consequently it is not surprising that he should, in common with others,
have accepted the original conclusions of Perroncito. Dr Giacomini
clearly perceives that, whatever precautions of a hygienic character are
suitable for the prevention of disease arising out of the consumption
of measly pork, the same, or at all events similar, measures ought
to be adopted with the view of checking tapeworm affections arising
from the ingestion of other kinds of meat, especially veal and beef.
Like Pellizzari, he is satisfied as to the human origin of the small
bladder worms found in cattle, and establishes this position not only
from the oft-quoted experiments of Leuckart and Mosler, but also from
those conducted by myself and Simonds in England, and by Professor
F. Saint-Cyr in France. From a careful review and consideration of
all the facts of the case, he recommended a more complete supervision
over the flesh of oxen before it is employed commercially, and greater
precaution when employing veal as food, by causing it to be subjected
to a high temperature, in order that the parasites may be killed before
it is ingested. It is evident that Giacomini thinks that a temperature
exceeding that of boiling-point is necessary for the destruction of the
beef and veal measles, since he immediately adds, “Though experiments
have not been made with the object of ascertaining the amount of
resistance of heat which the unarmed cysticercus can bear, yet, judging
by those conducted by Professor Perroncito on the measle of the hog,
we are in a position to say that a temperature of 135° Cent. (275°
Fahr.) is necessary for the destruction of an isolated Cysticercus,
whilst the heat should be raised from 150° to 200° Cent. (302° to 392°
Fahr.) for ten or fifteen minutes, in order to ensure the complete
destruction of the Cysticerci encapsuled in the interior of a piece
of meat.” I have abridged this portion of Giacomini’s text, because
his statements are pretty much the same as those already quoted from
Perroncito (as cited by Tommasi). But, in the next place, Dr Giacomini
is in error when he states that experiments had not been performed on
the Cysticerci of the ox. So far from this being the case, similar
experiments had long previously been conducted by Dr Lewis in India; and
these researches had quite as much to do with the measles or Cysticerci
of beef as they had with those of the hog, if not more. Naturally but
few foreign investigators can have had access to the work in which
Lewis’s experiments were originally recorded, and to which, therefore,
I must call their attention. Thus, Dr Tommasi has fallen into the error
of supposing that the investigations of Lewis were made in England. It
is of very little moment where the experiments were carried on, but
Tommasi’s statement (appendix, loc. cit., p. 161), wherein he says that
Pellizzari’s experiments, in which he himself took part (_ai quali
io stesso ho assistito_), are even more complete than those made in
England by Dr Lewis, and in Germany by Dr Küchenmeister, cannot be
allowed to pass unchallenged. If Tommasi had enjoyed the opportunity of
consulting Lewis’s original memoir, he would not have underestimated our
countryman’s labors. The memoir by Lewis is singularly complete, and
well-nigh exhausts all the facts that can have any interest in relation
to the question of public health. Towards the close of his essay he
expressly states, as the result of investigation--“(1) That exposure
to a temperature of 120° Fahr. for five minutes will not destroy life
in Cysticerci, but that they may continue to manifest indications of
life for at least two or three days after such exposure; (2) that
exposure to a temperature of 125° Fahr. for five minutes does not kill
them; but (3) after being subjected to a temperature of 130° Fahr. for
five minutes, they may be considered to have perished. After exposure
to this and higher temperatures, in no instance have I been able (he
adds) to satisfy myself that the slightest movements took place in
their substance when examined even under a high power. At least, it
may be confidently asserted that, after exposure for five minutes to
a temperature of 135° to 140° Fahr., life in these parasites may be
considered as absolutely extinct” (p. 139). Thus the statements of Lewis
and Pellizzari were in perfect accord; and seeing that their conclusions
were alike the result of very careful and independent inquiry, it seemed
as if the question at issue was finally solved. These investigations
made it perfectly clear that Cysticerci of all kinds, whether found in
veal, beef, or pork, could not retain their vitality when exposed to a
temperature of 60° Centigrade, or, in other words, 140° Fahr.

The rather severe strictures made on Perroncito’s earlier experiments
induced the Turin professor to go over the subject more carefully, when
he obtained excellent results. He finally ascertained that Cysticerci
perished at a temperature below 50° C. (122° Fahr.). In May, 1877, Dr
Perroncito furnished me with an account of his researches. With the
exception of a few verbal alterations, for which I am responsible,
Perroncito wrote as follows:

“In order to resolve the highly important question of the tenacity of
life of the Helminths and corresponding larval forms, I made since 1871
a very long series of experiments on the _Cysticercus cellulosæ_, which
were published almost at the same time with others of the same kind,
made by Dr Lewis in Calcutta. Towards the end of 1874 Mr Pellizzari,
of Florence, disputed the results of the investigations which I had
made known two years before, _i.e._ in 1872, and agreed with Dr Lewis,
who had stated already that the _Cysticercus_ exposed to a temperature
of 55° C. can be held for dead after five minutes, and also with Dr
Cobbold, who thought the temperature of 60° C. quite enough to kill it.
But the characters he (Mr Pellizzari) relied upon, needing the exactness
and precision required to enlighten and persuade in the most important
scientific questions, gave rise to a mistrust in the most scrupulous
amongst the men devoted to biological pursuits and to several hygienic
measures on the part of the sanitary inspectors with regard to infected
pork. Therefore, my conclusions, argued from the experiments made in
1871-72, were still those followed by the most important Italian cities,
and approved in principle by the superior Board of Health in 1873. I
expressed doubt then about the _Cysticercus_ dying at a temperature
lower than 100° C., and some person misconstrued these doubts, saying
that I had contradicted myself in my work. However, as I could not
assert they died at 80°--100° C., I only noticed the alteration of color
and cohesion which happened in the _Cysticercus_ exposed to various
degrees of temperature, to the end that I might contribute usefully to
the solution of the difficult question, and concluded that ‘if we could
not be sure of the _Cysticercus_ dying at 80°-100° C., it was certain
at all events that they perished at 125° or 130° C.’ Not wishing to
prejudice the question, I never said that they did not die at 80°--100°
C., but simply stated that at this temperature we could not be certain
of their death.

“Now, after a large number of experiments, I have been able to
ascertain with exactness the lowest degree of temperature required to
kill infallibly the _Cysticercus_ and other parasites of animals. The
means I made use of for this kind of investigation were Mr Schulze’s
heating table, the neutral tincture of carmine, the tincture of
hæmatoxylon, and breeding experiments.

“My method is founded essentially--

“(_a_) On the fact that the _Cysticercus_ when it is fresh and is
stretched and conveniently prepared in pure water, or in chloride of
soda very much diluted, and afterwards brought gradually from the
temperature of the ambient air to that of the body of higher animals and
to degrees of heat still more elevated, until life is extinct, keeps
moving to and fro with more or less energy throughout its body, using
especially its suckers and proboscis.

“(_b_) On the greater imbibing power of the dead tissue generally, which
is undoubtedly far more apparent in insects and plathelminths.

“(_c_) On the experiments made to ascertain the value of the two
above-stated facts.

“If, after having prepared a _Cysticercus_, newly extracted from a pig
in the way we have pointed out, we examine it with a microscope on M.
Schulze’s heating table, we find that usually it begins to move after
30° or 35° C., and each moment with greater activity, especially after
38°, 40°, 42°, 44°, 45° C. The temperature being raised progressively,
we see that the _Cysticercus cellulosæ_ puts a stop to its movements
occasionally at 45-46° C., seldom at 47° C., more frequently at 48°
C., sometimes at 49° C.; and, in fifty and more experiments, only one
_Cysticercus_ was able to live on beyond 49° C., standing still at 50° C.

“As soon as it stands still the parasite is dead. In fact, if we
lower again the temperature gradually to that of the ambient air,
and if afterwards we raise it a second time, we pass through all the
intermediate temperatures without the Cysticercus showing the least
signs of life.

“But a more convincing proof of the death of the parasite is got from
the greater imbibing power of the tissue when life is extinct, the same
over the whole body of the plathelminths, and their larval forms. If
we dip the _Cysticercus_ alive with its head stretched in the neutral
tincture of carmine or hæmatoxylon we can leave it there even two, four,
eight, ten, or twelve hours and more, without the head coloring or a
real imbibition taking place; this begins only after the _Cysticercus_
is dead, so that if the _Cysticercus_ is brought first to a temperature
hot enough to kill it (with M. Schulze’s tables to one of 48°, 49°, 50°
C.) and dipped afterwards in the above-mentioned tinctures, it colors
intensely in less than 45°, beginning from the head, and onwards to the
extremity of the cyst of the tail. The head colors more intensely and
rapidly than the neck, as it is covered with very numerous calcareous
corpuscles, which are not met with so frequently in the remaining part
of the body.

“_Cysticercus cellulosæ_ of the pig, and that of the _Tænia
mediocanellata_ of the calf, brought gradually to a final temperature,
the first of 50° C., and the second of 44°, 45°, and 47° C., and then
swallowed alone, or with a piece of butter or crumb of bread, never
produced the _Tænia_ in the valiant students who voluntarily undertook
to make the experiment of swallowing them.

“My investigations were extended to other kinds and forms of Helminths,
and the results were always the same, so that, abiding by the same
principles, I was able to ascertain that--

“1st. The _Cysticercus cellulosæ_ of the pig dies sometimes at 45°
C., more frequently at 47° C., ordinarily at 48° C., very seldom
reaches alive 49° C., and is quite an exception when it resists for
a few moments the temperature of 50° C., so that we can say that the
_Cysticercus_ brought gradually up to this temperature most assuredly
dies if it is kept there longer than one minute.

“2nd. A _Cysticercus cellulosæ_, extracted by Professor Raymond from the
conjunctiva of a child’s eye, died between 45° and 46° C.

“3rd. The _Cysticercus_ of the _Tænia mediocanellata_ dies sometimes at
44° C., very often at 45° C., and does not resist a temperature superior
to 46° C.

“4th. The _Cysticercus pisiformis_ of the rabbit, like the _cellulosæ_,
dies sometimes at 45° and 46° C., but generally stands still and
perishes at 47° and 48° C.

“5th. A _Cysticercus tenuicollis_ died at 49° C.

“6th. The _scolici_ of the _Cœnurus cerebralis_ of a sheep died at 42° C.

“7th. The _scolices_ of the cysts of _Echinococcus polymorphus_ die
generally between 47° and 48° C., and in no case amongst those I have
experimented on did it reach 50° C. alive.

“8th. The _Tænia cucumerina_ died, one at 43° C., and a second parasite
at 45° C.

“9th. A few individuals of _Tænia serrata_ of the dog died at 50° C.

“10th. Two individuals of _Tænia perfoliata_ of the horse died, the
first at 45° C., the second at 50° C.

“11th. The embryos of the _Filaria microstoma_ of the horse began to
stand still at 46-47°, and all died at 48° C.

“12th. The embryos of the _Filaria megastoma_ of the horse’s stomach
died at 47° C.

“13th. The _Trichina spiralis_, both free and in a cyst, in several
experiments always died at 48° C.

“14th. The embryos of the _Strongylus filaria_ of the sheep stood still
at 50° C.

“15th. Probstmayer’s viviparous oxyurids, the infusoria of the colon and
cæcum of the solipeds, and the psorosperms of the liver of the rabbit
did not stir at all.

“Each experiment lasted about ten minutes, and the temperature rose from
8-10° C. to 45-46° C. in six to eight minutes; and from 46° to 50° in
one minute. These experiments have a great value, both scientific and
practical, as they show, on one side, which is the lowest intensity of
heat sufficient to kill always the _Cysticercus_, the _Trichina_, and
other parasites, reducing thus by far the tenacity of life generally
attributed to a large number of Helminths and corresponding larval
forms. They assure us, moreover, of the harmlessness of the flesh
infected by the above-mentioned parasites, when it is cooked in such
a manner as to reach the temperature of 50° C. over all points of the
pieces, even though it be kept at such a degree of heat not longer than
five minutes.

“In a piece of leg of pork the _Cysticerci_ were found alive in all
places not yet putrefied twenty-nine days after the animal had been
slaughtered. On the other hand, in the dry muscles of a calf the
_Cysticerci_ of the _Tænia mediocanellata_ were all found dead fourteen
days after the slaughtering of the animal. I have ascertained that
putrefaction of the flesh is fatal for the two larval forms of these
different kinds of helminths.”

In a subsequent communication received from Professor Perroncito towards
the close of the year 1877 he writes:

“At the last meeting, held on April 23rd, I made a statement to
the Medical and Surgical Society of Turin, of the results of other
experiments tried by heating at M. Schulze’s table and by the
imbibitions with the neutral tincture of carmine, through which I came
to the conclusion that the _Cysticerci_ of the _Tænia mediocanellata_
die sometimes at 44° C., now and then at 45° C., and always at 46° C.
I therefore concluded that they could in no case survive at 47° C. and
48° C. when they were maintained at this temperature at least five
minutes. But to the end of more fully corroborating the facts I had
thus communicated, I, contemporaneously with these, made some breeding
experiments with the same _Cysticerci_ on bold and courageous students
who generously offered themselves for the benefit of science.

“Consequently I am now enabled to state that neither Mr Gemelli nor
Dr Ragni contracted the _Tænia_, though each of them had eaten a
_Cysticercus_ of the _Tænia mediocanellata_ previously, and respectively
subjected to a temperature of 45° C. and 47° C. The larvæ were properly
prepared and submitted to gradual heating on the above-mentioned table,
and swallowed when they no longer gave signs of life. In like manner no
generation of the _Tænia_ took place in the body of Mr Martini, who ate
the _Cysticercus_ brought to a temperature of 44° C. It was maintained
at this degree of heat during a period of about three minutes, and
swallowed whilst a very slight movement was still visible in a portion
of its neck.

“In another student, on the contrary, who ate a living _Cysticercus_
of the _Tænia mediocanellata_, the tapeworm reached its maturation in
fifty-four days and eliminated the two first proglottides. It threw
off two more on the fifty-eighth day, and thirty on the sixtieth.
Sixty-seven days after swallowing the _Cysticercus_ this courageous
young man, having, like his three companions, taken some kousso and
castor oil, emitted the strobila. It was furnished with 866 rings, but
destitute of the neck and head. Its measurement afforded a total length
of 4·274 mètres.

“Adding now to the 866 proglottides the thirty-four already eliminated,
900 would be the number of the segments; and reckoning the length of
each of the latter to be fourteen millimètres, we should have had the
_strobila_ (deprived of the head and neck) reaching a length of 4·75
mètres. Further, calculating the head and neck to be eight millimètres
long, a total length of 4·83 mètres would be the result.

“From all these facts we may conclude that the _Tænia_ has, in our
instance, reached an approximative length of seventy-two millimètres a
day, affording a daily production of 13·43 proglottides.”

In relation to requirements of state medicine I have thought
Perroncito’s researches sufficiently valuable to be quoted at some
length; but their chief interest culminates in the worm-feeding
experiments. Excellent in all respects as was the conduct of the
medical students who, with Professor Perroncito’s approval, swallowed
living specimens of the _Cysticercus bovis_, the intentional ingestion
of beef measles is by no means a novelty. Eight or ten years back Dr
Oliver (after explaining to one of the selected victims the possible
consequences of the experiment) induced a Mahommedan syce or groom and a
Hindoo boy to swallow perfectly fresh and living beef measles. In this
way Dr Oliver successfully reared the _Tænia mediocanellata_ in India,
and he was thus enabled to fix the amount of time necessary for the
full growth of the strobila. Many other persons have displayed an equal
amount of zeal in the cause of helminthology, by partaking of the larvæ
or germs of other parasites. Thus, at the risk of repetition, I may
state that Möller many years ago swallowed the slender-necked hydatid
(_Cysticercus tenuicollis_) in the hope of infesting himself with _Tænia
marginata_. Several persons have defiantly swallowed trichinised flesh.
Professor Leuckart and some of his pupils also courageously swallowed
the eggs of _Oxyurides_, and they had the infinite satisfaction of
noticing the young worms in their fæcal discharges some fifteen days
afterwards. Dr Crisp ate part of the cooked flesh of an animal that had
died of cattle plague, and I myself partook of moderately cooked meat
which I knew to be swarming with psorosperms. These obscure organisms
were by some persons considered to be either a cause or product of
the rinderpest. They will be noticed in my account of the Protozoal
parasites.

For the purpose of advancing science and the welfare of the people,
there are scores of persons always to be found ready to make personal
sacrifices of the kind undertaken by Drs Ragni, Martini, and Gemelli.
Unfortunately for English science there are not wanting people in
this country who are prepared to threaten with fines and imprisonment
any _savant_ who may think it desirable to perform a similar set of
feeding experiments on animals. Invaluable for good as our experimental
investigations have already been, it would seem as if it were the
deliberate aim of these sentimental obstructives to put a stop to the
acquisition of all useful knowledge in the future.

In reference to the rate of growth of tapeworms, Professor Perroncito’s
determinations are useful, inasmuch as they verify certain ascertained
facts with precision and confirm the general conclusion that had been
drawn by practical helminthologists from various sources of information.
In regard to the number of proglottides proper to a sexually mature
tapeworm, the circumstance that Perroncito’s calculation was made
without the head and a portion of the neck of the worm being present
shows that it cannot be relied on absolutely; nevertheless, as far
as it goes, it tends to confirm what Leuckart had long previously
stated. I have possessed myself of upwards of thirty perfect beef
tapeworms expelled from my patients, and in some of the specimens it
was noticed that the segmentation-rings in the region of the neck were
far more crowded together than they were in others. I also possess a
perfect _Tænia mediocanellata_, removed post mortem. Though the rate
of growth may be the same from day to day, yet experience has shown
that the number of proglottides actually cast off varies exceedingly.
Küchenmeister’s estimate of the average number agrees in the main with
what we have ourselves observed (five to twenty daily); and here again
Perroncito’s investigations serve to verify the general correctness of
our previous determinations.

To return to Pellizzari’s researches, one of the most important
questions is that which relates to the prevalence of tapeworm. In this
connection he first brings forward some very interesting and instructive
data that had been previously communicated to the Medico-Physical
Academy of Florence by Professor Marchi. On the occasion referred to
Marchi had stated that, out of thirty-five Tæniæ which he had examined,
only one belonged to the species known as _Tænia solium_; all the other
thirty-four being of the unarmed type, or _Tænia mediocanellata_.
Reflecting on this striking fact, and also on the circumstance that
he had in vain begged his colleagues to send him specimens of _Tænia
solium_, Marchi seems to have missed the very palpable explanation of
this otherwise strange phenomenon. “How does it happen,” exclaimed
Marchi, “that, notwithstanding the occurrence of 13,000 kilogrammes of
the flesh of measled hogs in the public butcheries, I have seen but one
specimen of _Tænia solium_, whilst thirty-four cannot have originated
from the pig?” “The wherefore is obvious enough,” replies Pellizzari,
“because our hygienic regulations demand that the flesh of the hogs
be raised to a temperature of 60° Cent. (140° Fahr.);” and he then
himself immediately proceeds to ask another question, namely, as to
how it happens that the _Tænia solium_ is so frequently seen in other
places. To his own question Pellizzari responds by remarking--(1)
that there are not so many precautions (of a sanitary kind) taken in
other places; and (2) that the people elsewhere consume more slightly
salted or uncooked meat, as sausages and so forth (_come salame giovane,
salciccia e via dicendo_). Pellizzari, having explained that Marchi’s
thirty-four tapeworms must all have arisen from the consumption of
the Cysticercus of the ox, then goes on to speak of the prevalence of
tapeworm in Florence, even in little children. This last-named feature,
he says, is due to the circumstance that raw meat is frequently employed
as a restorative (_come cura ricostituente_). “Thirty years ago,”
remarks Professor Pellizzari, “it was just as difficult to find a single
_Tænia mediocanellata_ as it is now easy to find a great number of these
worms; and all because it is nowadays customary to eat the flesh of
the ox either insufficiently cooked or raw. This absolute inversion of
the facts of the case affords proof of the correctness of the position
sustained by me, to the effect that the cooking of meat up to the degree
of temperature necessary for ebullition ensures the destruction of the
Cysticerci.” Notwithstanding this statement of his own, Pellizzari
thinks that the interference of inspectors may be pushed too far, and
thus serve to bring about the very disasters which it should be their
supreme object to prevent. Thus, he argues against the suggestions of
those who would entirely prevent the sale of measly meat, and who would
only permit, as obtains in the province of Modena, the melting down of
the fat of hogs. Very strict measures of this sort would, as he says,
constitute a radical means of entirely stamping out _Tænia_, but he also
very judiciously reminds the sanitarian (_igienista_) that “such a step
would be a serious thing for the tradesman, bringing injury not only
to the municipal administration, but also proving an encouragement to
smuggling. In this way the public health would sustain worse injury by
the inducement held out to the owners of infected animals to slaughter
them in secret butcheries, thus little by little withdrawing the meat
from the superintendence of the public officials. By the adoption of
fraudulent measures there would be a daily consumption of diseased
meat; and thus also, while the public administration would suffer loss,
the public health, on the other hand, would gain nothing.” In effect
Pellizzari says, if we advise the employment of more severe and radical
measures than those already in vogue in Florence, we should overburden
the tradesman, almost compel him to defraud the exchequer by smuggling,
and greatly injure the public health.

The facts and explanations advanced by Italian writers regarding the
causes of the endemic prevalence of tapeworm, are in perfect harmony
with those previously obtained from other sources. Respecting these
causes there is much that is both new and interesting. The eighth
annual report of the sanitary commissioner of the Government of India
had already made us acquainted with the fact that during the year 1869,
out of 13,818 head of cattle slaughtered in the stations of the Upper
Punjab, 768 beasts were found to be infected with measle-cysts. This,
as I have remarked (Tommasi’s edit., p. 54), “affords a rate of 5·55
per cent., being a considerable diminution of the proportion observed
in 1868, when the percentage gave a total of 6·12. The reduction was,
without doubt, due to the vigilance and enlightenment of the army meat
inspectors. The prevalence, however, of tapeworm does not bear relation
to the number of animals infested with Cysticerci so much as to the
actual number of Cysticerci developed in infected animals. I have
frequently pointed out the inadvisability of condemning and burying
the carcases of measly oxen, whether there be few or many Cysticerci
present, and I have stated, on trustworthy evidence, that even the
presence of a few Cysticerci is deemed by some inspectors a sufficient
reason for rejecting the entire animal. Such a waste should never be
allowed. In regard to the numbers of ox-measles present in particular
instances, I have elsewhere adduced some remarkable facts communicated
to me by Dr Joseph Fleming, of the Indian Army Medical Staff. None of
my experimental animals, though fed with scores of ripe proglottides,
yielded such an abundance of Cysticerci as Dr Fleming encountered in
Punjab cattle. In one pound weight of the psoas muscles Fleming counted
no less than 300 Cysticerci.” From this it follows that the flesh of a
largely infested animal is capable, under the circumstances of ration
distribution and imperfect cooking, of originating numerous tapeworms.

Not many years back the leading medical journal of this country
challenged me to produce evidence as to the injuriousness of beef and
mutton from Cysticerci. The writer stated in his article that I had
“failed to produce a single specimen of beef or mutton measles” which
had not resulted from experiments conducted “at the Royal Veterinary
College;” and he said, further, “that butchers, fleshers, and
veterinarians were practically right in refusing to adopt the opinion of
Dr Cobbold, that measled beef or mutton is produced to any great extent”
independently. How palpably I endured a species of unjust reproach for
being somewhat in advance of the knowledge current at the time may be
gathered from the voluminous evidence which has since cropped up from
various parts of the world. It was, indeed, mainly through experiments
conducted at the Royal Veterinary College, and reported in the ‘Lancet,’
that professional men in India first became acquainted with the
possibility of finding Cysticerci in beef.

The statements of Dr Joseph Fleming, who was one of the foremost in
discovering cystic disease in cattle, have since received abundant
confirmation. The Indian Government Reports given in the February
issue of the ‘Madras Monthly Journal of Medical Science’ for 1873 are
especially instructive. Referring to the prevalence of Cysticercus in
the ration beef at Jullundur, in the Punjab, the Inspector General
(India Medical Department) reports as follows:

“Cysticercus was first noticed here in the beef tendered at the Royal
Artillery ration stand in May, 1868. For some two years previous to this
date condemnations of cyst-infected meat had been frequent at Peshawur,
Rawul Pindee, Meean Meer and several other stations in the upper part of
the Punjab, and here I had often detected the parasite in meat exposed
for sale in the bazaars, but no trace of it had been observed in the
Commissariat beef, either by myself or any other medical officer who had
preceded me.

“From May, 1868, to November, 1869, ‘cyst’ was more or less frequently
found both at the Artillery and 92nd Highlanders’ ration stands; but
since the latter date it has almost entirely disappeared.

“The following table shows the quantity of meat destroyed on this
account during 1868 and 1869:

  +--------+-----------+------------------+---------------+
  | Years. |  Months.  | Number of cattle | Weight of meat|
  |        |           |    infected.     |   destroyed.  |
  +--------+-----------+------------------+---------------+
  |      { | May       |         4        |     412 lbs.  |
  |      { | June      |         1        |      77  "    |
  |      { | September |         1        |     130  "    |
  | 1868 { | October   |        10        |   1,763  "    |
  |      { | November  |        14        |   2,010  "    |
  |      { | December  |        12        |   1,785  "    |
  +--------+-----------+------------------+---------------+
  |      { | January   |        21        |   4,062 lbs.  |
  |      { | February  |        16        |   2,341  "    |
  |      { | March     |        14        |   2,209  "    |
  |      { | April     |         5        |     856  "    |
  | 1869 { | May       |         2        |     220  "    |
  |      { | June      |         1        |     122  "    |
  |      { | July      |         1        |     194  "    |
  |      { | August    |         3        |     464  "    |
  |      { | September |         2        |     218  "    |
  |      { | October   |         4        |     615  "    |
  |        +-----------+------------------+---------------+
  |        |   Total   |       111        |  17,478 lbs.  |
  +--------+-----------+------------------+---------------+

“The whole of this meat was otherwise well fed and of excellent quality.
The waste of so much good food led me to make inquiries; 1st, as to the
sources from which the cattle obtained the Tænia ova, and the best means
for preventing their infection; and 2ndly, as to whether or not any evil
results followed the consumption of this meat when properly cooked.

“From information obtained from the Commissariat Officer I found--1st.
That the infected cattle had been purchased by native dealers from
various parts of the district, not from any particular locality. 2ndly.
That when brought in they were lean, and on an average required from two
to three months’ feeding at the Commissariat cattle yards before they
were fit for the shambles. 3rdly. That their food consisted of the grass
they could pick up on the grazing grounds of cantonments, supplemented
by such an allowance of grain and _bhoosâ_ as their condition required.

“They were supposed to be watered at a trough with water drawn from a
well, but on closely inquiring as to this, it transpired that they very
frequently were taken to a large dirty tank near the yard for their
water. The question which occurred to me was, were the cattle infected
before their purchase by the Commissariat, or was there anything in
their feeding to account for it after purchase? I am inclined to the
latter opinion for several reasons, thus:--In the large number of
the diseased cattle, the Cysticerci were of remarkably small size;
many of them having no capsules, except such as were formed by the
surrounding structures, and not being more than 1/8 to 1/4 of an inch
in diameter. Although the dry food given to the cattle was doubtless
good, still much of the water they got during 1868 was probably filthy.
The tank previously referred to was situated close to the huts of the
camel drivers. These men are all Mussulmans from Cabul, Peshawur, or
thereabouts, and many of them are infected with _Tænia mediocanellata_.
Human filth was often to be seen on the banks of the tank, and
microscopic examination of mud and stagnant water taken from the margin
exhibited _Tænia_ ova.

“The conditions above shown must have been eminently favorable to
keeping up a constant supply of ova, and the fact that Cysticercus
entirely disappeared from amongst the cattle a few months after means
had been taken to secure them a good supply of well water, seems to
confirm the view that this tank must have been the source of a large
amount of, if not all, the infection.

“It has been suggested that Cysticercus can be detected before the
animal is killed by an examination of the tongue. In exceptionably
severe instances this is probably correct, but then it would be equally
observable in some other parts of the body. Major Biggs, Commissariat
Officer here, tells me of an animal he saw at Rawul Pindee, in which
immense clusters of cysts could be felt at the root of the tongue and
under the skin in several parts. After examining a very large number of
tongues of ‘cysted’ animals, my experience is that it is found in the
soft muscles and cellular tissues at the root of the tongue, perhaps
more frequently than anywhere else; but I have never seen a case in
which there was a chance of detecting it before death.

“The most common situations in which it has occurred in the ration meat
have been the gluteal, psoas, and lumbar regions. In many instances only
from one to ten cysts have been found on cutting the carcase into small
pieces, and I have no doubt that it often passed without detection.

“During 1868 and 1869 I from time to time obtained pieces of beef badly
infected with _Cysticercus_, and made some experiments as to the results
of its consumption under different conditions.

“After explaining to them the possible consequences of eating it a
buttock of beef studded with _Cysticercus_ was given to three natives of
low caste. They all declared that they were free from _Tænia_, or, to
use their own term, “Kadhu dana.” The meat they cooked in their own way.
These men were under my observation for some six months. Two of them had
no symptom of _Tænia_, but the third, who was a low-class Mahommedan
syce, and had probably eaten the meat in a very raw state, developed a
_Tænia mediocanellata_ in about three months.

“My own sweeper ate this cyst-infected beef regularly two or three times
a week for some months. He cooked it well generally as an ordinary stew,
and has never shown a sign of having tapeworm.

“Into the food of a boy of low Hindoo caste, but who had never eaten
beef, two scolices of Cysticercus were surreptitiously introduced, the
result being that, between three or four months afterwards, he applied
for some tapeworm medicine.”

[The two successful experiments here reported are evidently the same
as those that I have referred to (p. 72) as having been performed by
Dr Oliver, of the Royal Artillery, stationed at Jullundur. The report
continues as follows:]

“_Tænia mediocanellata_ is very common amongst the Mussulman population
of the Punjab, and from reliable sources I am informed that the lower
classes amongst them are in the regular habit of eating half-cooked
beef; indeed, prefer it so, and it is amongst these people that tapeworm
is so prevalent.

“But it is not only thorough cooking that is required to guard soldiers
in India from the ill effects of eating measly meat; there is want of
cleanliness in the general arrangements of the kitchens and serving of
meals, which must offer great facilities for the introduction into the
food of Cysticercus.

“Barrack cooks, unless constantly looked after, are utterly careless
as to the washing of chopping blocks, tables, dishes, &c. The dish or
pot cover on which the meat is placed when raw is often used without
washing for serving the piece up for dinner, and I have myself picked
up a _Cysticercus_ from the table on which a cook was preparing food.
The dangers too of the parasite being conveyed by the cook’s unwashed
hands to the plates in which meals are served, and the common practice
of using the same knife for cutting up meat, and afterwards, without
washing it, for other culinary purposes, must not be overlooked. With
good selection and careful feeding there seems to be every probability
that Cysticercus would soon almost or completely disappear from our
Commissariat cattle. If they were entirely stall-fed and watered from
wells there could scarcely be a possibility of infection after their
purchase.

“Perhaps with the trench system of conservancy, which will necessitate
the growing up crops, a sufficient quantity of root and other green
produce may be obtained from cantonment lands set apart for this
purpose, to supply green fodder for the cattle.”

The important question as to whether the presence of cysts detected
at the root of the tongue could be made available for the purposes of
diagnosis was made the subject of special report through the agency of
executive Commissariat officers, and they testified to its practical
valuelessness in the following terms:

“_Jullundur._--No appearance of cyst has been found at the root of the
tongues of any of the cattle. A medical officer was asked for assistance
in making search for the cysts, but he also found none.

“_Rawul Pindee._--It is utterly impossible to discriminate before
slaughter, from any outward symptoms, cattle that are cyst infected.

“Every endeavour has been made to discover by close and careful scrutiny
before slaughter the cyst-infected cattle, but the result has been in no
way satisfactory.

“_Sealkote._--All endeavours to discover any symptoms of the infection
by examination of their tongues, while the animals were living, have
been unsuccessful.

“_Mooltan._--The mouth and tongue of a large number of living cattle
have been examined before slaughter, but in no single instance has the
infection been so detected.

“Dr. Ross’s plan of examining the tongues of all animals at time of
purchase is not feasible, as they are usually very wild and frightened,
and often dangerous to approach.

“_Peshawur._--In probably 99 cases out of 100 it is utterly impossible
to discover cyst infection in cattle previous to slaughter by
examination of their tongues. In only one instance has it been so
discovered, and that was from the animal’s having a number of small
lumps over the body which were also apparent on the back part of the
tongue. When the tongue is infected the ‘cyst’ lies so far at the very
root of it that it cannot be seen in the live animal.”

From Mooltan a specially interesting report was made by Dr Alexander
Neill, who says:--

“I have carefully examined the mouth and tongue of a large number of
living cattle, and of those slaughtered for issue as rations, and in no
single instance did I find such cysts. These cattle were healthy.

“In a case that died, and in which cysts existed, I could discover
nothing abnormal in or under the tongue.

“If such ‘cysts’ exist, or if such enlargements of the sublingual glands
are found, I argue that they are not a diagnostic sign of what is termed
‘cyst infection,’ or more correctly ‘_Cysticercus bovis_,’ for in the
recent outbreak of cattle disease in England, one most prominent symptom
of that disease was a bunch of grape-like swelling under the tongue,
which in advanced cases suppurated, and to a casual observer would have
been called cysts or ‘bags of matter.’

“If such swellings are found in a bullock that is sick, it is merely
symptomatic of an inflamed condition of the whole mucous surface of the
intestinal canal, and not of any localised disease, such as Cysticercus,
the above-mentioned swellings being merely inflamed sublingual glands.

“In the pig the diagnostic sign of swellings of the glands or ‘cyst’
under the tongue is not found in ‘Cysticercus,’ and the disease called
‘measles’ is not ‘Cysticercus,’ but a mere superficial inflammation of
the skin and a symptom of fever. ‘_Cysticercus cellulosus_,’ as its
name shows, infects the cellular tissue only of the pig, and cannot be
discovered in life by any abnormal condition of skin.

“In ‘measles’ these swellings are found, because intestinal mucous
membrane sympathises with eruption on the skin and are then merely
inflamed glands, not cysts.”

Dr Neill concludes his report by remarking that the larvæ of the
beef tapeworm can “only arrive at maturity in the mucous membrane of
horned cattle,” and not in the cellular tissue. This is an error on
Dr Neill’s part; but in adducing these instructive extracts from the
Government Reports my chief object has been to show the prevalence of
Cysticercus in the North-West Provinces of the Indian Peninsula. I may
say that a large proportion of my tapeworm-infected patients have been
officers from the Punjab, and one of these victims told me that when he
superintended the serving out of rations to the troops, “he (and those
who acted with him) sent the meat away to be burnt, even when they only
detected a single cyst in any given carcase.” It is needless to remark
that such a waste of valuable food is altogether reprehensible.

Some people, including not a few of the profession, make light of the
occurrence of tapeworm, and I have seen many patients who had been told
by their usual medical advisers that the presence of the worms was of
little consequence. To account for this wide-spread error there is some
basis in the fact that by far the majority of infested persons suffer
only the trifling inconvenience arising from the passage _per anum_ of
the proglottides; moreover, the less civilised the tapeworm-bearers
happen to be, the less are they likely to suffer. The recorded
experience of Kaschin, before referred to, where 500 hospital patients,
in the Baikal district, had tapeworm, although all of them were being
treated for other disorders, affords another argument tending to the
same conclusion. On the other hand, amongst Europeans only a small
percentage of tapeworm-patients suffer severely. But without trenching
upon the symptomatology and prognosis of tapeworm disease, I may remark
that I have (in my Manual) summarised the whole facts of cysticercal
prevalence within the compass of two brief propositions:--1. The
prevalence or the rarity of Cysticerci in cattle in any given country
must be determined primarily by the habits of the people; for since the
beef measle can only result from the ingestion by the ox of the eggs of
the _Tænia mediocanellata_, it is clear that the degree of infection of
cattle will correspond with the facilities offered by egg-dispersion.
2. It may be affirmed that the frequency of this particular species
of tapeworm amongst the people occupying any given area will bear a
strict relation to the amount of underdone measly beef consumed by the
inhabitants.

Another question, and one of great interest to sanitary science,
is that which I have raised in reference to the period that nature
requires for the destruction of the Cysticerci, or, in other words,
for the performance of a natural cure by calcareous degeneration of
the parasites. I have shown that all kinds of tapeworm larvæ (measles,
bladder-worms, cœnuri, and so forth) have a natural life-epoch assigned
to them, and in one of my experiments on a Dutch heifer or young cow I
demonstrated that a period of ten months was more than sufficient to
ensure the perfect destruction of the Cysticerci of cattle. Moreover,
this law or process of natural cure is not limited to cestode parasites,
but affects all other kinds of internal parasites in one or other of
their juvenile stages of growth. In the flesh of my experimental animal
I estimated that there were not less than 12,000 of these degenerated
Cysticerci. This positive contribution to our knowledge of the limits
assigned by nature to the epoch of larval activity is not merely one of
abstract scientific interest, but it has important practical bearings,
inasmuch as it points out in what way an entire herd of cattle (known
to be measled by the post-mortem examination of one animal previously
selected for the purpose, or for that matter, by the rather barbarous
act of excising and examining a fragment of the muscle of a living one)
may be freed of its parasitic guests; and it also shows how all risk of
propagating tapeworm, apart from the question of subjecting the flesh
to a certain temperature, may be effectually prevented. The stockowner
has but to remove his animals for six or eight months to localities
where no fresh infection can occur, when, at the expiration of the time
mentioned, all those Cysticerci that existed in the beasts at the time
of the transfer will have perished. The flesh of the animals may then be
eaten with impunity, whether well cooked or raw. This is an important
teaching deducible from experimental inquiry, and I am rather surprised
that it has hitherto escaped the notice of persons who, though they
affect to ignore the value of scientific researches, are particularly
anxious to parade their practical knowledge, which, unhappily, too often
proves a mere cloak for ignorance.

The memoir by Giacomini already quoted (p. 65) affords interesting
details respecting a case in which there was a most unusual degree of
infection of the human body by Cysticerci. Dr Giacomini instituted a
searching comparison between the human measles procured by himself and
those of the pig sent to him by Professor Perroncito. In the human
Cysticerci he noticed a greater adherence of the capsule to the enclosed
measle, and he also observed that while the human measle-heads either
displayed thirty-two, or in some few cases thirty-four hooks, in two
differently sized circles of fifteen or sixteen each, the pig-measles,
on the other hand, carried only twenty-four hooks to the double circle
of equal circumference; consequently the hooks appeared to be more
crowded together in the human parasite. This fact, Giacomini remarks,
does not of itself constitute an essential specific difference, since
variations of the kind not unfrequently occur in Cysticerci occupying
one and the same host. Even the beef-measle is not necessarily confined
to one species of host, since Zenker has succeeded in rearing it in a
goat.

Although the substance of the above-recorded conclusions was originally
communicated by me, anonymously, to a professional periodical, I have
considered this work a suitable medium for a fuller discussion of the
subject. Its importance in relation to the public health and the supply
of meat-food has not received the attention it deserves.

BIBLIOGRAPHY (No. 13).--_Balert, B._, ‘Die Bandwürmer,’ &c. (pamphlet),
1877.--_Bertolus, G._, ‘Diss. sur les metamorph. des cestoïdes,’
Montpellier, 1856.--_Cobbold, T. S._, “On the Production of the
so-called ‘Acute Cestode Tuberculosis’ by the Administration of the
Proglottides of _Tænia mediocanellata_” (with Mr Simonds), in ‘Proc.
of the Royal Society’ for May 4th, 1865; repr. in the ‘Veterinarian’
for 1865, p. 513.--_Idem_, “Experimental Investigations with Cestoid
Entozoa,” in ‘Linn. Soc. Journ.,’ vol. ix, p. 170; also for July, 1865,
p. 141.--_Idem_, “On Beef, Pork, and Mutton, in relation to Tapeworms,”
in ‘Brit. Assoc. Rep.’ for 1865, p. 102, and in ‘Appendix to Treatise on
Tapeworms and Threadworms,’ 1st Edit., 1866, p. 73; also in ‘Med. Times
and Gaz.’ for Sept. 23rd, 1865, p. 343.--_Idem_, “Remarks on Entozoa,”
in ‘Brit. Assoc. Rep.’ for 1865, p. 102; also on “Cystic Entozoa from
Veal and Mutton,” in the ‘Path. Soc. Trans.’ for 1866, vol. xvii, p.
462.--_Idem_, “Entozoa found in a Westphalian Ham;” report in ‘Athenæum’
for March 27th, 1869, p. 442; also in ‘Brit. Med. Journ.’ for March
20th, 1869.--_Idem_, “Note on Beef Measles from a Cow,” in ‘Path. Soc.
Trans.,’ vol. xvii, p. 463, 1866; also in the ‘Lancet’ for Feb. and
August, 1865, p. 249.--_Idem_, ‘Entozoa,’ &c., p. 235 _et seq._, 1864;
and in ‘Supp.,’ sections iii, iv, v, 1869.--_Idem_, ‘Tapeworms,’ 3rd
Edit. (with 100 cases), 1875, p. 11.--_Idem_, ‘Manual of the Internal
Par. of Domesticated Animals,’ chap. iii to vi, 1874.--_Idem_, ‘Worms,’
Lectures i to xi, 1872.--_Idem_, “On the Parasites of our Food-producing
Ruminants (Cantor Lectures),” in the ‘Journ. of the Soc. of Arts,’
1871.--_Idem_, “On the Entozoa of Abyssinia” (Lecture), in ‘Lancet,’
1867.--_Idem_, “Remarks on Eighty Cases of Tapeworm,” ‘Lancet,’ June,
1874.--_Idem_, “Revised List of Entozoa, with notes and references
(the beef tapeworm, No. 15, and the beef measle, No. 25),” in the
‘Veterinarian,’ Dec., 1874, and Feb., 1875.--_Idem_, (anonymously),
“Cysticerci, being a review of the writings of Pellizzari, Tommasi,
Perroncito, Lewis, Giacomini, &c.,” contributed to the ‘Lond. Med.
Record,’ 1874, p. 642 _et seq._; repr. in the ‘Veterinarian,’ Jan.,
1875.--_Idem_, “Notice of a Discussion by Paul, Martineau, Créquy,
Delioux de Savignac, Trasbot, and others, respecting the Source and
Treatment of Tapeworm,” ‘Lond. Med. Rec.,’ July, 1874, p. 472.--_Idem_,
“Review of the Writings of Oliver, Fleming, Hewlett, Lewis, and others,
on the Cystic Disease of Animals,” ‘Lond. Med. Rec.,’ June, 1873, p.
339.--_Idem_, “Further Experimental Researches with the Eggs of the
Beef Tapeworm,” the ‘Veterinarian,’ Aug., 1875.--_Idem_, “Remarks on
Perroncito’s Researches,” the ‘Veterinarian,’ Dec., 1877.--_Dardel, A._,
“Sulla frequenza della Tenia in Savoia,” ‘Giorn. d’Accad. di Med.,’
1868.--_Davaine, C._, ‘Traité’ (1. c. Bibl. No. 1), 1860.--_Idem_, “Les
Cestoides,” in ‘Dict. Encyclopédique des Sci. Med.,’ 1875.--_Fleming,
J._, ‘Indian Med. Gaz.,’ 1869.--_Fock, H. C. A. L._, ‘De Lintworm en
het middel om hem mit te drijven,’ Utrecht, 1878.--_Fritsch, G._,
“Zur differentiellen Diagnose von _T. solium and T. mediocanellata_,”
‘Berliner Klinische Wochenschrift,’ 1874.--_Gamgee, J._, “Entozoa
in Veal and Beef” (Letter on), ‘Lancet,’ 1865.--_Giacomini, C._,
‘Sul _Cyst. cell. hominis_ e sull _Tænia med_, contrib. alla studio
dei Cestoidi Parrassiti dell’ Uomo,’ Torino, 1874.--_Heller, A._,
“Darmschmarotzer,” in von Ziemssen’s ‘Handbuch der speciellen Pathol.
und Therapie,’ s. 598 _et seq._, 1876.--_Hewlett_, ‘Health Officer’s
Report,’ Bombay, 1870.--_Krabbe, H._, ‘Beretning om 100 Tilfælde af
Bœndellorm hos Menesket iagttagne her i Landet (Aftryk af Ugeskrift for
Læger),’ 1869.--_Küchenmeister, F._, ‘Ueber Cestoden im Allgemeinen
und die des Menschen insbesondere, hauptsählich mit Berücksichtigung
ihrer Entwickelungsgeschichte, geographischen Verbreitung, Prophylaxe
und Abtreibung; specieller Theil. Zittau,’ 1853.--_Idem_, ‘Parasiten’
(1. c. Bibl. No. 1), 1855, Eng. Edit., London, 1857.--_Laboulbéne, A._,
“Sur les Tænias,” ‘Mém. de la Soc. Méd. des Hôpit.,’ 1876.--_Idem_,
‘Anat. Pathologique,’ 1879, p. 962.--_Letheby_, “On Diseased Meat,”
‘Med. Times and Gaz.,’ 1867.--_Leuckart, R._, ‘Die Menschl. Par.,’ Bd.
i, s. 285 and s. 747, 1864.--_Levi_, “Della freq. della tenia,” &c.,
‘Giorn. Veneto di Scienz. Med.,’ 1874.--_Lewis, T. K._, “A Report on the
Bladder Worms found in Beef and Pork” (‘App. B. to 8th Ann. Rep. of the
Sanit. Commiss. with the Gov. of India’), Calcutta, 1872.--_Masse, E._
et _Pourquier, P._, “Le Tænia inerme et la lardrerie du Bœuf, Nouvelles
Expériences,” &c., in ‘Montpellier Med. Journ. Mens. de Méd.,’ p. 220,
1876.--_Mosler_, ‘Helminthogische studien und Beobachtungen,’ Berlin,
1864. _Neill, A._, “Letter, forming the fifth of a series of important
articles on Cyst-infected Cattle, and on the prevalence of Cysticercus
in Beef,” reported by the Inspector General (I. M. D.), in the ‘Madras
Monthly Journ. of Med. Sci.,’ Feb., 1873; repr. in the ‘Veterinarian,’
July, 1873.--_Nitsche, H._, “Untersuchungen ueber den Bau der Tænien,”
‘Sieb. und Köll. Zeitschrift,’ 1873.--_Oliver_, “Rejections of Ration
Beef on account of Cystic Disease” (l. c. _supra_), ‘7th Rep. of the
Commiss.,’ p. 82, Calcutta, 1871.--_Perroncito E._, “Della panicatura
negli animali,” ‘Annali della R. Accad. d’Agricolt. di Torino,’ vol. xv,
1872.--_Idem_, “Sulla morte del _Cyst. cell._ delle carni del majale;”
_ibid._, 1872.--_Idem_, “Ueber die Lebenszähigkeit des _Cyst. cell._ und
anderer Eingeweidewürmer,” ‘Zeitsch. f. prakt. Veter.-Wissenschaften,’
Bern, 1876.--_Idem_, ‘Della Grandine o Panicatura nell’ Uomo e negli
animali,’ Torino, 1877.--_Idem_, “Esperimenti sulla produzione del
cisticerco nelli carni del bovini, coll’ amministrazione di anelli
della _tænia med._ dell’ uomo,” ‘Lo Studente Vet.,’ Parma, 1876, p.
146.--_Idem_, “Sulla tenacita,” &c., _ibid._, 1877, p. 194.--_Idem_,
“Esperimenti sulla prod. del Cyst. della _T. med._ nelle carni dei
Vitelli,” ‘Estr. della Annali d. R. Accad. d’Agric. di Torino,’ vol.
xx, 1877.--_Idem_, “On the Tenacity of Life of the Helminths, and their
corresponding Larval Forms in Man and Animals,” the ‘Veterinarian,’
July, 1877, p. 457.--_Idem_ (with similar title, including notice of
experiments), the ‘Veterinarian,’ Dec., 1877; partly from ‘Osservatore
Gaz. d. Cliniche di Torino,’ and from ‘Archivvo per le Sci. Med.,’ vol.
i, 1877.--_Idem_, “On the Tenacity of Life of the _Cysticercus_ in
the flesh of Oxen, and on the rapid development of the corresponding
_T. mediocanellata_ in the Human Body,” the ‘Veterinarian,’ Dec.,
1877, p. 817.--_Probstmayr_, ‘Jahrb. der Münchener Thierarzneischule,’
1869.--_Rochard_, “Note sur la fréquence du _Tænia mediocanellata_ en
Syrie, et sur la présence du cysticerque qui lui donne naissance, dans
la chaire musculaire des bœufs de ce pays,” in ‘Bulletin de l’Acad. de
Méd.,’ 1877, tom. vi, p. 998.--_Thudichum, J. W. L._, “On the Parasitic
Diseases of Quadrupeds used as Food,” ‘Privy Council Med. Officer’s
Rep.’ 1865.--_Sommer, F._, “Ueber den Bau und die Entwickelung der
Geschlechtsorgane, von _Tænia mediocanellata_ und _T. solium_,” in
‘Siebold and Köll. Zeitschrift,’ Bd. xxiv, s. 499, 1874.--_St Cyr_,
“Deux Experiences,” &c., ‘Journ. de l’Anatomie, de Robin,’ p. 504; and
in ‘Lond. Med. Rec.,’ by Higgs, vol. i, 582, 1873.--_Tommasi, T._,
‘Appendice (to Cobbold’s) Parasiti Interni degli Animali Domestice,’
p. 161, Firenze, 1874.--_Van Beneden, P. J._, “Iconographie des
Helminthes ou des vers parasites de l’homme” (Vers Cestoïdes, pl.
ii), Louvain, 1860.--_Welch, F. H._, “Observations on the Anatomy of
_Tænia mediocanellata_,” ‘Quart. Journ. of Microsc. Science,’ vol.
xv, 1875.--_Zenker_, in ‘S. B. Soc.,’ Erlang. iv, s. 71.--_Zurn_,
‘Zoopathologische und physiol. Untersuchungen,’ 1872.

_Tænia solium_, Linneus.--This cestode was formerly known as the common
tapeworm, but in England it is of far less frequent occurrence than the
beef tapeworm. In contradistinction it is best to speak of it as the
pork tapeworm. Though only one specimen is usually present, the bearer
may entertain several worms of this species at one and the same time.
The parasite has been known to science from the earliest times, though
possibly not earlier than the measles, or Cysticerci, from which it
originates. Hippocrates, Pliny, and Aristotle describe the full-grown
worm; and, in regard to the larvæ, some have gone so far as to express
their belief that the prohibition of swine’s flesh as food amongst the
Jews and other Oriental people, was dictated by sanitary considerations.
Weinland has suggested that the Mosaic commandment not to eat pork may
have originated in an old popular notion “of the fact that tapeworm
sometimes comes from this food.” Weinland’s hypothesis is probably
correct, for if one supposes Moses to have been supernaturally informed
that pork would produce tapeworm disease, one naturally asks why veal
and beef should not also have been prohibited, seeing that these meats
also frequently harbour tapeworm larvæ.

A perfect pork tapeworm presents itself to the eye of the observer as a
long, soft, white, jointed strobile, which, when alive, elongates and
contracts itself with facility. Though commonly spoken of as a single
creature, it is a compound of many individuals. These are variously
called “cucurbitini,” “zooids,” “proglottides,” “segments,” “links,”
or “joints.” When fully grown the segments are capable of detaching
themselves and of enjoying a free and independent existence. Very
annoying it is to the human bearer to be continually reminded of his
unwelcome “guests” as they seek to quit his interior.

The head of _Tænia solium_ is seldom seen in anatomical museums,
although the evacuation of pork tapeworms is not of rare occurrence.
Placed under the microscope, the head displays a quantity of dark,
almost black, pigment granules, which are abundant at the base of
the rostellum and in the neighbourhood of the hook-fangs. They are
equally present and abundant in the pork measle proper, and in measles
derived from the human subject. The cephalic hooks of this cestode are
comparatively large, those of the greater circle individually measuring
1/156″, whilst the smaller hooks have a length of about 1/220″.

[Illustration: FIG. 23.--Head of _Tænia solium_. Highly magnified. After
Van Beneden.]

The male reproductive organ consists of a number of small vesicles or
sacs, in which filiform spermatozoa have been detected, these latter,
when ripe, being conducted by a _vas deferens_ into a seminal pouch,
from which a canal passes laterally into the penis; the latter organ,
in its retracted condition, being lodged within a flask-shaped sheath
or cirrhus-pouch. The female organs are somewhat more complicated. They
consist of two masses of vitelligene glands occupying a limited space, a
small ovarium, a centrally-placed and largely-developed branched uterus,
canals of outlet leading from all these organs, and enlargements of
the main passages to form internal seminal reservoirs; also, a vaginal
canal, which is widened at its termination to form a receptaculum for
the curved penis.

In addition to the above-named structures, the entire series of joints
from the head downwards are traversed by a set of vascular canals,
which are doubled in the region of the head. These form the so-called
aquiferous system. There are two main channels, one passing down on
either side of the worm, both being connected by transverse vessels,
which occur singly at one end of every joint.

The eggs in their mature condition are globular, and contain a
six-hooked embryo. They present an average diameter of 1/694 of an
inch, the shell itself measuring about 1/4000″ in thickness. In 1856
I observed that many of the eggs, whilst still within the uterine
branches, displayed an outer envelope, very delicate in structure and
totally dissimilar from the egg-shell proper. This has since been
more accurately described by Weinland, Van Beneden, and Leuckart. The
outer membrane, according to the last-named authority, constitutes
the primitive yolk-membrane, within which a part of the yolk-contents
separates to form the true egg and embryo by a process of daughter-cell
formation. The remaining part of the yolk forms a granular mass, being
probably concerned in the formation of the true chitinous shell. The
true shell displays a series of radiating and circular lines; the
former, however, are more conspicuous than the latter, being due,
according to Leuckart, to the presence of a series of fine rod-like
chitinous elements, which are formed on the external surface of the
original true shell-membrane. The enclosed embryo is furnished with six
boring spines, arranged in three pairs, its granular body being invested
by an extremely delicate skin-membrane, which is separated from the
inner surface of the shell by a clear transparent fluid. The embryo
measures 1/1250″ in diameter.

The scolex or higher larval stage of growth forms the well-known pork
measle or _Cysticercus_ (_telæ_) _cellulosæ_ of authors. The smallest
measles found by Leuckart measured 1/25″ in length. They were obtained
from the brain, liver, and intermuscular substance of a pig fed with
proglottides about thirty days previously. Only those specimens,
however, occurring in the liver at this early period displayed an
outer membrane proper to the worm itself, the others being simply
invested with capsules formed out of the connective tissues of the
host. Many measle-masses in the same host were much larger, presenting
an average diameter of 1/6″. The smallest already displayed a smooth,
transparent, homogeneous, outer, cuticular membrane, overlying a
double, finely-granular corium, the latter being traversed by a branched
system of aquiferous vessels. These vessels proceed from a central spot,
which marks the position of the so-called head-cone, or _receptaculum
capitis_. It is, in fact, the first well-marked indication of that
flask-shaped capsule within which the head, neck, and body of the
Cysticercus is formed, and which Goeze long ago very aptly compared to
a lantern. As growth proceeds, a central granular mass forms the true
foundation of the head, its upper or stalk-like extension becoming the
future neck and body. Further changes result in the evolution of the
internal water-vascular system, the calcareous corpuscles, the marginal
transverse foldings of the body, the four suckers, the rostellum, and,
in particular, the double coronet of hooks. All these metamorphoses were
minutely followed and described by Leuckart, who found the development
of the larva to be completed within the space of ten weeks.

As regards the injurious effects of this parasite upon man, it may be
said to act prejudicially in three separate ways. I have remarked in
my ‘Entozoa,’ that this parasite may cause disease and death both by
its action in the larval and adult states. It may likewise injure us by
rendering the flesh of swine unwholesome.

When one or more sexually-mature tapeworms have developed themselves
within the human intestine, they are apt to give rise to a variety
of unpleasant symptoms, more or less marked according to the habit
or irritability of the patient. According to Davaine (p. 103 of his
‘Traité’) the principal features are “vertigo, noises in the ears,
impairment of sight, itching of the nose and anus, salivation, dyspepsia
and loss of appetite, colic, pains over the epigastrium and in different
parts of the abdomen, palpitation, syncope, the sensation of weight
in the abdomen, pains and lassitude in the limbs, and emaciation.” In
ordinary cases there is always more or less anxiety and restlessness;
but in severe cases the sympathetic symptoms are very strongly
marked, showing themselves in hysterical fits, chorea, epilepsy, and
epileptiform seizures, attended by more or less alarming convulsions.

Amongst some of the more interesting and remarkable cases recorded in
our English journals, I may instance that of Mr Hutchings, where a
complete cure followed the evacuation of the worm which had produced
convulsions. Mr Tuffnell records a case where irritability of the
bladder and stricture of the urethra were entirely dependent on
tapeworm, as proved by the subsequent recovery. At a meeting of the
Pathological Society, in 1853, Dr Winslow mentioned his experience of
three or four cases of mania arising from tapeworm; whilst on the same
occasion Drs Ryan and Davey each recorded a similar instance. A case has
also been previously published by Mr W. Wood. At a meeting of the London
Medical Society, held on the 10th of April, 1837, Dr Theophilus Thomson
(during an interesting discussion on this subject) stated the facts of
a case where the presence of tapeworm had given rise to a tumultuous
action of the heart, this symptom entirely disappearing after evacuation
of the worm. Our journals likewise (anonymously) record a considerable
number of cases from foreign sources. Thus, in the ‘London Medical
Gazette’ for 1840, there is the case of a lady, aged thirty-seven,
who had convulsions attended with a complete loss of consciousness,
the separate fits lasting an hour at a time. The passage of the worms
effected a complete cure. In the same journal for 1838, there is also
the case of a younger lady (aged twenty-seven) suffering from epilepsy,
in whom a complete cure had been similarly brought about; here, however,
in addition to a single specimen of the _Tænia solium_, there were
two lumbrici present. This journal also gives Ettmüller’s case, where
eighteen tapeworms were the cause of hysteria; and likewise the case
published by Steinbeck, where the symptoms presented an altogether
peculiar character. More precise references to some of the above cases
will be found in the ‘Bibliography’ below; and I may also refer to
my published lectures on Helminthology and especially to my separate
work on Tapeworms, where particulars of one hundred cases are briefly
recorded. These were all average cases occurring to me whilst in private
practice. Davaine’s book also abounds with remarkable cases.

Whilst the adult worm is capable of producing serious and even fatal
mischief to the bearer, the larvæ or measles much more frequently prove
fatal. The Cysticerci may develop themselves in almost any situation
in the human body, but they occur most commonly in the subcutaneous,
areolar, and intermuscular connective tissue; next, most commonly in
the brain and eye, and lastly, in the substance of the heart and other
viscera of the trunk.

In my ‘Entozoa’ I have stated that probably not less than one hundred
cases have been observed where death had resulted from Cysticerci in the
brain. Griesinger alone collected between fifty and sixty such cases.
Mental disturbance occasioned by the presence of measles in the brain
may occur with or without epilepsy. When Griesinger states that “the
epilepsy from Cysticercus is in all respects like cerebral epilepsy and
the psychical disturbances have nothing characteristic about them,” he
tacitly admits the impossibility of correct diagnosis during life.

Since the publication of Griesinger’s well-known memoir on Cysticerci
of the brain, many similar cases have appeared, and amongst the more
recent of these is one by Dr Frédet in which the victim was a young
man twenty-two years of age. Though apparently in good health he fell
dead in the street; the fatal result being due to the presence of a
Cysticercus within the _pons Varolii_.

Many other cases of earlier date are especially noteworthy. Thus Mr
Toynbee recorded a case where an hydatid (which I take to have been the
_Cysticercus cellulosæ_) situated in the middle cerebral fossa beneath
the _dura mater_, but in this instance death ensued from other causes.
Mr Ottley gives the case of a woman aged forty, where an undoubted
Cysticercus in the brain gave rise to distressing fits, convulsions,
and death. Then, again, there was Dr Burton’s workhouse patient, only
twenty years of age, who was found dead in bed, but who at the time
of admission merely complained of pain in the head. After death, four
hydatids (_Cysticerci_) were found in the _tuber ancillare_ at the
summit of the spinal marrow. M. Bouvier’s similar case is also reported
in our periodicals. Of instances where Cysticerci occupied the cavity
of the eye, we have one or two cases by Mackenzie of Glasgow, one by
Mr Rose of Swaffham, and others by Windsor, Logan, and Estlin. Amongst
the more peculiar cases, I may mention that described by Dr Greenhalgh
in the ‘Lancet’ (1848), where the Cysticercus was lodged within the
substance of the lip. Five similar cases are likewise recorded by Heller
of Stuttgard. Then there is Dupuytren’s case of a Cysticercus ensconced
within the great peroneus muscle; and also Fournier’s, where several of
these scolices were said to have been found in a boil. The so-called
_Trachelocampylus_, discovered by Frédault in the human brain, was
neither more nor less than a common _Cysticercus cellulosæ_.

It is worthy of remark, as Griesinger has also observed, that in cases
where the Cysticerci have taken up their temporary residence in the
brain, they are usually found, post mortem, in the grey cortical or
peripheral substance of the cerebrum. The particulars of such a case are
given in my ‘Entozoa’ where the victim suffered from epileptic fits due
to the presence of numerous Cysticerci (fig. 24). The patient was under
Mr Hulke’s care.

[Illustration: FIG. 24.--Head of a _Cysticercus_ removed from the brain.
Magn. 5 diam. with detached hooks. Original.]

As regards infection by the adult worm it is not alone sufficient that
we avoid underdone _meat_, as brought to the dinner-table, but we must
be especially careful to have our sausages well cooked. Under ordinary
circumstances, we are safe for the following reasons:--No respectable
butcher will knowingly supply us with pork or with sausages which are
measled. Even in the case of underdone meats, in whatever way prepared,
it is usually only a small portion which is unaffected by cooking. As
we have seen a temperature of 140° Fahr. is sufficient to kill the
Cysticerci.

The successful rearing of pork measles by experimentation with the
eggs of _T. solium_ has been accomplished by many helminthologists,
amongst whom may be particularised Van Beneden, Leuckart, Küchenmeister,
Haubner, Gerlach, and Baillet. The converse experiment of rearing the
adult worm from the Cysticercus was first successfully undertaken by
Küchenmeister on a condemned criminal; Leuckart, Humbert, and others
having repeated this method with more or less success.

The dangers arising from infection by swallowing the larval worms or
six-hooked embryos are not easily avoided. Our flesh, like pork, thus
becomes measled, although certainly not to the spawn-like extent so
often seen in the lower animals. A single measle is sufficient to
prove fatal; and this humiliating contingency, moreover, is one which
we can never be absolutely certain of avoiding. We become the “host”
or bearer of the measle by swallowing the fully-developed eggs of the
_Tænia solium_. This we may do directly by handling fresh tapeworms,
whose eggs, being concealed under our nails or in our clothing, may
subsequently be swallowed, and develop within us accordingly. Even a
thorough washing of the hands will not ensure absolute security. In like
manner, those who partake of choice salads, prepared from the stores
of the market-gardener, run a certain amount of risk. The vegetables
may have been manured with night-soil containing myriads of tapeworm
eggs, or they may have been watered with fluid filth into which the
eggs were accidentally cast. In such cases, one or more tapeworm ova
will be transferred to the digestive organs, unless the vegetables
have been very carefully cleansed. In the same way, one perceives how
fallen fruits, all sorts of edible plants, as well as pond, canal, and
even river water procured from the neighbourhood of human habitations,
are liable to harbour embryos capable of gaining entrance to the
human body. One individual suffering from tapeworm may infect a whole
neighbourhood by rendering the swine measly, these animals, in their
turn, spreading the disease far and wide. As already remarked, measles
sometimes occur in great numbers in different parts of the body. Among
the more remarkable cases of the multiple Cysticerci are those recorded
by Delore (1864) and Giacomini (1874). In M. Delore’s case, about 2000
were obtained post mortem. Of these, 111 occurred in connection with
the nervous centres, eighty-four being in the cerebrum, twenty-two in
the membranes of the brain, four in the cerebellum, and one within the
substance of the medulla oblongata. Dr Knox published a less notable
instance in the ‘Lancet’ (1838); and in the year 1857, Dr Hodges,
of Boston, U.S., published a case where the cysts, which in size he
compared to rice grains and coffee beans, were felt subcutaneously. The
coexistence of Tænia and Cysticerci in the same individual has also
recently been observed in France (‘Lond. Med. Rec.,’ 1875). Besides
these, several remarkable instances have lately been reported by Davy,
Tartivel, and others.

To the literature already quoted in connection with the beef tapeworm
the following may be added:

BIBLIOGRAPHY (No. 14).--_Aran_, in ‘Archives Gén. de Médecine,’
1841.--_Baillet_, “Helminthes,” art. in ‘Bouley and Reynal’s Dict.
Vétérin.,’ tom. viii, 1869.--_Bécoulet_ and _Giraud_, “On Cysticercus
in the Brain,” ‘Bullet. de la Soc. Méd. de Gand,’ 1872; and in
‘Lond. Med. Rec.,’ Feb., 1873.--_Birkett, J._, Cases, ‘Guy’s
Hosp. Rep.,’ 1860.--_Bouchut_, “Cyst. in the Brain,” ‘Gaz. des
Hôp.,’ 1857, and ‘Journ. für Kinderkrankheit.,’ 1859.--_Bouvier_,
‘Bullet. de l’Acad.,’ 1840.--_Burton_, in ‘Med. Times and Gaz.’
(supposed hydatids), 1862.--_Cobbold_, “On Measly Meat and Measles
in Man,” the ‘Veterinarian,’ 1876.--_Czermack_, “Cysticerci causing
Insanity,” Corresp.--Blatt, 1838.--_Dalton, J. C._, “Cyst in the
Scrotum,” ‘New York Journ. of Med.,’ 1857.--_Davaine_ (see his
‘Traité’ for many additional references; p. 676).--_Davy, R._,
“Cysticerci in the Muscles,” ‘Rep. of Lond. Med. Soc.,’ ‘Lancet’
for Nov., 1876.--_Estling_, “Cases of Cysticercus,” ‘Lond. Med.
Gaz.,’ 1838-39.--_Frédet_, “Cysticercus in the _pons Varolii_,”
in the ‘Lancet’ for June 23rd, 1877 (p. 925), from ‘Giornale
Veneto de Scienze.’--_Fournier_, ‘Journ. des Connois. Med. Chir.,’
1840.--_Griesinger_, “On Cysticerci of the Brain,” from ‘Med. Jahrb.’
in ‘Med.-Chir. Review,’ 1863.--_Harley, J._, “Cyst. in the Brain,”
‘Lancet,’ 1867.--_Hodges, R. M._, “Specimens of _Cyst. cell._, felt
as small tumours just beneath the skin, varying in size from that of
a grain of rice to that of a coffee bean,” ‘Rep. of Boston Soc. for
Med. Improvement,’ in ‘Brit. Med. and Surg. Journ.,’ 1857.--_Hogg, J._,
“Obs. on Cysticercus,” in his ‘Manual of Ophth. Surgery,’ 3rd edit.,
1863.--_Holler, A._, “_Cyst. cell_., im Gehirne einer Geisteskranken,”
‘Allgem. Wiener Med. Zeitung,’ 1878.--_Logan, R._, “Probable Cases
of _Cyst. cell_.,” removed by Robertson, ‘Ed. Med. and Surg. Journ.,’
1833.--_Mackenzie, W._, “Cyst in the Eye,” ‘Lancet,’ 1848, ‘Lond.
Med. Gaz.,’ 1839.--_Mazotti, L._, “Caso di numerosi cisticerchi del
cervello e delle meningi,” ‘Rivista Clin. di Bologna,’ 1876.--_Mégnin,
P._, “La Ladrerie du porc et le _Tænia solium_,” ‘La France Médicale,’
1876.--_Putz, H._, “Ueber die Lebenszähigkeit des _Cysticercus
cellulosæ_,” &c., ‘Zeitsch. f. pr. Vet.-Wissenschaften,’ 1876.--_Rainey,
G._, “On the Structure, &c., of _Cyst. cell._,” ‘Phil. Trans.,’
1857.--_Rizzetti, G._, “Rendiconto Statistico dell’ufficio d’igiene
di Torino per l’Anno 1873.”--_Rudall, J. T._, “Cyst. in the Brain,”
‘Australian Med. Journ.,’ 1859.--_Tartivel, De A._, “Cysticerques
multiples dans le tissu cellulaire sous-cutané et dans certain
viscères,” ‘Rec. de Méd. Vet.,’ 1876.--_Von Gräfe, A._, in ‘Arch. für
Ophthal.,’ 1857.--_Wells, S._, Bourman’s Case, ‘Ophth. Hosp. Rep.,’
1860.--_Windsor, J._, “Cyst. in the Eye,” ‘Brit. Med. Journ.,’ 1861.

_Tænia tenella_, Cobbold.--I have long been acquainted with the fact
that there is a comparatively small human tapeworm which cannot be
referred to either of the foregoing species. In the absence of
experimental proof, I incline to the belief that the worm in question
owes its existence to measly mutton. The sheep harbours an armed
Cysticercus (_C. ovis_), which I regard as the scolex of _Tænia
tenella_. The specific name (_tenella_) was originally applied by
Pruner to a cestode six feet in length, which he found associated with
a larger tapeworm. This latter he called _Tænia lata_. Whilst Diesing
has pronounced Pruner’s _Tænia lata_ to have been a _T. mediocanellata_,
I, on the other hand, consider Pruner’s _T. tenella_ to have been
a _T. solium_. Mr J. C. Mayrhofer has suggested its identity with
_Bothriocephalus tropicus_. When, some years back, I applied the term
_T. tenella_ to a new tapeworm (of which I possess several strobiles)
I was quite unaware than any similar nomenclature had been adopted by
Pruner. From the few facts supplied by Pruner and Diesing, I cannot
suppose that our cestodes are identical. Unfortunately my specimens are
imperfect, wanting the so-called head. It is not possible to estimate
the length of the worm accurately, but the perfect strobile must measure
several feet.

On one slide I have mounted nine mature proglottides of a worm which I
procured on the 15th Dec., 1875. The segments measure, on the average,
exactly 1/10″ in length, and only 1/20″ in breadth. The uterine rosettes
are all full of eggs, and their branches so crowded together that I am
unable to ascertain their average number. The segments are perfectly
uniform in character, their reproductive papillæ alternating irregularly
at the margin.

In the autumn of 1872 I caused a lamb to be fed with the proglottides of
a tapeworm which I referred to this species. The animal was slaughtered
on the 22nd of January, 1873, when the result was stated to have been
negative. As I had no opportunity of examining the carcase, I cannot
feel quite sure that there actually were no Cysticerci present. On
several occasions I have detected measles in the flesh of animals, when
none were supposed to be present by those who either assisted me or
were professional on-lookers. Assuming my _Tænia tenella_ to be derived
from the sheep’s Cysticercus, I think it fitting to describe the mutton
measle in this place. Even if _T. tenella_ be not actually the adult
representative of the mutton measle (_Cyst. ovis_), it is quite certain
that the scolex in question gives rise to an armed tapeworm, and it is
almost equally certain that the adult armed cestode resides in man.
In Pruner’s case, which is by no means unique, we have seen that two
distinct species of cestode may coexist in the human bearer. It is quite
possible that some one may yet have the good fortune to detect the beef
tapeworm, the pork tapeworm, and the mutton tapeworm, all together in
one and the same host.

On five separate occasions I have detected measles in “joints” of
otherwise excellent and healthy mutton brought to my own table, and
supplied by the family butcher. On several other occasions I have had
these parasites brought under my notice; nevertheless, many persons
are either unaware of, or actually deny, the existence of these ovine
parasites. Thus, MM. Masse and Pourquier, in the ‘Montpellier Med.
Journ.’ for Sept., 1876, make the following statement: “The sheep, not
being subject to measles, it seems to us natural to employ the raw meat
of that animal whenever it is required for nourishment in the treatment
of diarrhœa, in weaning children, in phthisis, and for anæmics.”
Clearly, if MM. Masse and Pourquier could have brought themselves to
believe that English literature is worth consulting on such matters,
they would not have made this statement. Incidentally they also observe,
when speaking of beef measles:--“Un fait que nous avons remarqué et que
nous tenons à signaler, c’est que nous avons trouvé des cysticerques
nageant librement dans l’eau où nous avions plongé de la viande infestée
de ladrerie.” Certainly this is a novel experience. That measles should
not only get out of their cysts, but should have the power of “swimming
freely” in the water is a phenomenon which requires explanation. There
must have been some error of observation.

It was in the year 1865 that I discovered the mutton measle (_C. ovis_,
mihi); but I am not prepared to say that the parasite had never been
seen before, since it is alleged that a two-headed Cysticercus was
obtained by Fromage from the liver of a sheep (as cited by Davaine). Be
that as it may, my discovery was announced in a communication made at
the Birmingham meeting of the British Association in the autumn of 1865,
and subsequently at a meeting of the Pathological Society of London,
on the 3rd of April, 1866 (‘Path. Trans.,’ vol. xviii, p. 463). After
these dates further announcements and verifications appeared, amongst
which I can only refer to my remarks “On Beef, Pork, and Mutton, in
relation to Tapeworms,” forming an appendix to the first edition of my
work on Tapeworms, 1866; to the “Remarks on Cysticerci from Mutton,”
contained in the fourth chapter of the Supplement to my introductory
treatise on Entozoa, where a figure of the parasite is given, 1869,
p. 27; to Dr Maddox’s paper “On an Entozoon with Ova, found encysted
in the Muscles of a Sheep,” recorded in ‘Nature,’ May 15th, 1873, p.
59; to the ‘Monthly Microscopical Journal,’ June, 1873, p. 245; to my
further communications in the ‘Lond. Med. Record,’ Aug. 6th, 1873; to my
‘Manual,’ 1874, pp. 74 and 105, Ital. edit. ‘Nota Dell’ Autore,’ p. 133;
and especially to the article headed “The Mutton Tapeworm,” contained in
the 3rd edit. of my little volume on ‘Tapeworms,’ p. 12, et seq., 1875.

In regard to the measle itself, I spoke of it as smaller than the common
pork measle. The head is 1/30″ in breadth, and is armed with a double
crown of hooks, twenty-six in all, the larger hooks each measuring
1/160″ in length. The suckers are four in number, each having a breadth
of 1/100″. The neck and head are abundantly supplied with calcareous
corpuscles, being at the same time marked by transverse rugæ. The data
on which I founded my brief description of the scolex were chiefly based
on the examination of a specimen which had been procured by Prof. Heisch
from the interior of a mutton chop. Subsequently much fuller details
of the structure of the scolex were supplied by the illustrated memoir
of Dr Maddox (above quoted). This excellent microscopist, however,
announced the presence of immature ova within the Cysticerci themselves.
As the notion of the existence of eggs in larval cestodes was altogether
at variance with what we know of the phenomena of tapeworm life, I
suggested that the author might have mistaken the egg-shaped calcareous
corpuscles (which I found so abundant in my own specimens) for the ova.
In the interests of truth I felt bound to characterise certain of the
conclusions arrived at by Dr Maddox as simply incredible, but I regarded
his memoir as forming “an important contribution to our knowledge of
the structure of the mutton measle.” I had no idea that in pointing to
errors of interpretation I should offend the excellent author. However,
a long letter appeared in the ‘London Medical Record,’ in which Dr
Maddox showed that he was much vexed that I should have “impugned” the
“accuracy of his conclusions.” He defended his position with the support
of no less an authority than Dr Macdonald, F.R.S., the distinguished
Assistant Professor of Naval Hygiène at the Victoria Hospital, Netley.
Dr Maddox says:--“We were quite alive to the anomalous position. Hence
the exceptionability of the case rests on more than my own evidence.”
In regard to this unfortunate dispute I will only add the expression
of my conviction that Drs Maddox and Macdonald will eventually become
satisfied that no cestode scolex is capable of displaying either mature
or immature ova in its interior.

BIBLIOGRAPHY (No. 15). _Cobbold_ (l. c., _supra_), 1865-75.--_Idem_, “On
Measly Meat, &c.,” the ‘Veterinarian,’ Dec., 1876.--_Idem_, “The Mutton
Tapeworm (_T. tenella_),” No. 16 in my revised list of Entozoa, the
‘Veterinarian,’ Dec., 1874.--_Diesing, C. M._ (_Tænia tenella_, Pruner
nec Pallas), in “Revis der Cephalocotyleen,” ‘Sitzungsb. der Math.-Mat.
Class d. k. Akad. der Wissenschaften,’ Bd. xlix, s. 369, 1864.--_Maddox_
(l. c., _supra_), 1873.--_Mayrhofer, J. C._, ‘Die helminth. des
Menschen,’ Erlangen, 1854.--_Pruner_, ‘Krankheiten des Orients,’ s. 245,
1847.

_Tænia lophosoma_, Cobbold.--This is a good species notwithstanding the
doubts that have been expressed by Heller and others regarding it. I
have called it the ridged tapeworm in consequence of the presence of
an elevated line coursing the whole length of the body, which measures
about eight feet. The reproductive papillæ are remarkably prominent and
uniserially disposed throughout the entire chain of proglottides. It
is quite an error to suppose that this species is a malformed cestode,
or that it has any resemblance to Küchenmeister’s variety of tapeworm
from the Cape of Good Hope. Neither does it in the slightest degree
resemble the remarkably malformed _T. mediocanellata_ described by Mr
Cullingworth. Of the distinctiveness of this parasite as a species, any
one may satisfy himself by an inspection of the nearly complete strobile
preserved in the Pathological Museum attached to the Middlesex Hospital
Medical College. From the examination of several mature proglottides
detached from this specimen, I find their average breadth to be one
fifth of an inch, by three quarters of an inch in length. Their greatest
thickness does not exceed the 1/13th of an inch. The eggs resemble those
of other tapeworms, and offer a diameter of about 1/850″ from pole to
pole.

BIBLIOGRAPHY (No. 16).--_Cobbold_, “Parasites of Man,” in the ‘Midland
Naturalist,’ April, 1878, p. 98.--_Idem_, ‘Tapeworms,’ 1st edit.,
p. 52, 1866; 3rd edit., p. 27, 1875.--_Cullingworth_ (see Bibl. No.
18).--_Davaine_, ‘Les Cestoïdes,’ l. c., p. 573.--_Heller_, l. c., s.
594.

_Tænia nana_, Siebold.--As regards the dwarf tapeworm, unless Spooner’s
case be genuine, there is but one solitary instance on record of its
occurrence in the human body; moreover, we have no evidence of its
having existed in any other host. It was discovered by Dr Bilharz,
of Cairo, at the post-mortem examination of a boy who died from
inflammation of the cerebral membranes. Prodigious numbers existed. The
largest specimen measured only one inch in length. To the naked eye
these worms resemble short threads, and consequently they might very
readily be overlooked. The head is broad and furnished with a formidable
rostellum armed with a crown of hooks. These hooks have large anterior
root-processes, which, extending unusually forward, impart to the
individual hooks a bifid character. By far the best account of this worm
is furnished by Leuckart, to whom I am indebted for a specimen.

BIBLIOGRAPHY (No. 17).--_Cobbold_, ‘Entozoa,’ p. 244.--_Davaine_ (l.
c., Bibl. No. 2), p. 574.--_Heller_, l. c., s. 606.--_Küchenmeister_,
l. c., Eng. edit., p. 141.--_Leuckart_, l. c., Bd. i, s. 393.--_Von
Siebold_ and _Bilharz_, in Von Sieb. and Köll. Zeitschr., Bd.
iv.--_Spooner_, ‘Amer. Journ. Med. Sci.,’ 1873.--_Van Beneden_,
‘Iconographie,’ l. c., pl. iii, fig. 17.--_Weinland, ‘Diplacanthus
nanus,’_ l. c., p. 85.

_Tænia Madagascariensis_, Davaine.--This appears to be a well-defined
species although the head has not yet been seen. It probably forms the
type of a distinct genus. Dr Grenet, stationed at Mayotte (Comores),
twice encountered single specimens passed by two young children,
eighteen and twenty-four months of age respectively. The proglottides
have their genital pores uniserially arranged, and they show, in their
interior, remarkable egg-capsules, from 120 to 150 in number in all,
each containing from 300 to 400 eggs. These give a long diameter of
1/625″ for the outer envelope and 1/1250″ for the inner, or shell
proper. The embryo measures only the 1/2500 of an inch.

A full account of this parasite, with figures, is given by Davaine (‘Les
Cestoïdes,’ l. c., Bibl. No. 2, p. 577 _et seq._).

_Tænia marginata_, Batsch.--Although I possess no certain evidence of
the occurrence of this parasite in its adult condition in the human
bearer, yet there is a tapeworm in the Edinburgh Anatomical Museum
referable to this species, which was said to have been obtained from the
human body. This worm is very common in the dog.

The principal evidence demonstrating the occurrence of the larval
representative of this species (_Cysticercus tenuicollis_) in man, rests
upon the two cases recorded in Schleissner’s ‘Nosography’ of Iceland.
One of the alleged instances, however, has been proved by Küchenmeister
and Krabbe to be that of an echinococcus; so that, after all, there only
remains the solitary case observed by Schleissner himself, in which the
parasite can fairly be considered as the “slender-necked hydatid.”

To the above, however, may probably be added a specimen preserved in the
Anatomical Collection at King’s College, London. It was found connected
with an ovarian cyst.

_Tænia elliptica_, Batsch.--This parasite is readily recognised not
merely by its delicate form and small size, but also by the circumstance
of its supporting two sets of reproductive organs in each mature joint.
Their outlets are situated at the centre of the margin of each segment,
one on either side. Ordinarily infesting the cat, this worm is a mere
variety of the common _Tænia cucumerina_ of the dog. At all events,
from the evidence put forth by Eschricht, seconded by Leuckart, there
is every reason for believing that one or other of these closely-allied
varieties is liable to infest the human body. It was originally stated
by Eschricht that he had received a _Tænia canina_ which had been
passed by a negro slave at St Thomas, Antilles. This is a synonym of
_T. elliptica_, which must therefore be very rare in the human body,
possibly only occurring in the negro race.

In regard to the source of this parasite, it has been shown by Melnikow
that the scolex of _Tænia cucumerina_ resides in the louse of the dog
(_Trichodectes latus_), and thus it is exceedingly probable that the
scolex of _Tænia elliptica_ resides in the louse of the cat (_Trich.
subrostratus_). How man becomes infested is not so clear. Melnikow’s
paper on the juvenile state of this cestode is contained in the ‘Archiv
für Naturgeschichte’ for 1869, and is illustrated by a figure of the
measle.

_Tænia flavopuncta_, Weinland.--Regarded as a new species, the discovery
of this little tapeworm is due to the investigations of Weinland. In
Dr Jackson’s ‘Catalogue of the Boston Medical Improvement Society’ an
account of the contents of a phial is recorded as follows:--“Specimen
of Bothriocephalus, three feet in length, and from half a line to
one line and a quarter in width, from an infant. The joints are very
regular, except at one extremity, where they approach the triangular
form, are very delicate, and but slightly connected, as shown in a
drawing by Dr Wyman.” It is further stated that the infant was nineteen
months old, and that the worm was discharged without medicine, its
presence having never been suspected. It was presented by Dr Ezra Palmer
in the year 1842. On examining the fragments, Dr Weinland found, instead
of a solitary specimen, at least six different tapeworms, all of them
being referable to a hitherto undescribed species. There were no heads;
nevertheless, it was ascertained that the worms varied from eight to
twelve inches in length, the joints or segments being very broad, and at
the same time narrowed from above downwards. The parasite was named “the
spotted tapeworm,” in consequence of the presence of yellow spots near
the middle of the joint. They represent the male organs of reproduction,
the outlets of which, as in my _T. lophosoma_, occur all along one side
of the body or strobile. In Weinland’s estimation this parasite forms
the type of a new genus which he calls _Hymenolepis_. A full account of
the worm is given in his well-known essay (l. c., Bibl. No. 2).

_Tænia abietina_ and other varieties. I can only notice very briefly
certain cestodes which either present malformations or which may be
regarded as mere _varieties_. First in this series is Weinland’s _T.
abietina_. No one who has studied his ‘Beschreibung zweier neuer
Tænioiden aus dem Menschen,’ Jena, 1861, can doubt that it is a mere
variety of _T. mediocanellata_. The monstrosity described by him as
referable to _T. solium_ must also be referred to the beef tapeworm.
The variations in the character of cestode proglottides is practically
infinite. A museum might be filled with them. Most common with _T.
mediocanellata_, these varieties more or less prevail with other
species. Thus I have seen them in Tæniæ and Bothriocephali alike. I have
obtained segments of _T. mediocanellata_ having sexual outlets on both
sides of the proglottis, so regularly disposed in a few segments as to
suggest the notion of a new species. The coalescence of several segments
into one compound segment is frequent, but the most remarkable specimen
that I have seen is one contained in the museum of the Royal College of
Surgeons. In the old Hunterian catalogue the specimen is described as
“two joints of the _Tænia solium_, with a number of orifices in unequal
series on either side.” As stated in the new catalogue of the series,
prepared by myself, the “lower segment is furnished with twenty-two
sexual orifices, one of which is situated in the central line” on
the ventral surface (as in Bothriocephali). References to this and
other specimens in the Hunterian Collection will be found below (see
_Pittard_). In regard to Weinland’s conjectural _Tænia acanthotrias_,
based on the circumstance of his having found a Cysticercus that
presented three rows of hooks on its rostellum, I need only say that if
such a _Tænia_ were found it would only turn out to be a malformed _T.
solium_. The specimens, however, are none the less interesting. Very
remarkable and altogether exceptional characters are presented by the
strobile of the cestode described by Mr Cullingworth, of Manchester, and
of which I possess specimens. Here, apparently, at least two tapeworms
are joined together throughout the entire chain of proglottides without
intermission. The three margins of each compound segment project
at equi-distant angles. Could we have secured the head we should
certainly have found six or eight suckers present, since the finest
neck-segments showed that the malformation pervaded the entire colony
of zooids, sexually mature and otherwise. Mr Cullingworth’s specimen is
so remarkable that I subscribe full particulars of the case in his own
words. He says:--“A respectable married woman, named Ann H--, forty
years of age, residing in Salford, brought to my out-patient room at St
Mary’s Hospital, Manchester, on September 3rd, 1873, a few segments of
tapeworm as a sample of what she had been passing per anum for about
two years. Although never in the habit of taking meat absolutely raw,
she told me, on inquiry, that she was particularly fond of tasting it
when only partially cooked. The segments were unlike anything I had
seen before, and I took them home for examination, ordering the patient
meanwhile a draught containing a drachm of the oil of male fern, and
giving her strict injunctions to bring to me every fragment that passed
away as a result.

“On September 17th she brought me portions of a tapeworm corresponding
throughout to the segments I had already seen, and measuring altogether
nine feet in length. Unfortunately, the head was not to be found.
Along the middle line of every segment in the body a crest or ridge
runs longitudinally, and in the centre of the margin of this crest the
genital pore is situated. [In 304 segments examined, only four had the
genital opening placed laterally. One segment had two openings, viz.
one at the lateral margin and the other in the crest.] Underneath the
segment there is a longitudinal groove, and the lateral portions are
folded together by the apposition of their under surfaces. When hardened
in spirit the section of a segment presents a three-branched appearance,
the branches being of unequal length, but placed at equal angles. The
uterus sends vessels into the crest as well as into the sides of the
segment; and the contained ova are exactly like the ova of an ordinary
_Tænia mediocanellata_. Wedged in between, or attached to, the segments
here and there, is a stunted and ill-shaped joint, with irregular and
unequal sides. A mature joint measures from five eighths of an inch to
three quarters of an inch in length, and about half an inch in breadth,
and the breadth or depth of the crest is usually one eighth of an inch.

“There are only two specimens that I can find on record at all similar
to the one here described, and both of these differ from it in several
important particulars. Küchenmeister mentions, as a variety of _Tænia
mediocanellata_, a tapeworm sent to him from the Cape of Good Hope by
Dr Rose. This worm possessed a longitudinal ridge, but he describes its
mature segments as ‘extremely massive’--more than an inch in length and
3/5″ in breadth. The genital pores, too, were irregularly alternate, and
not situated on the crest. On March 20th, 1866, Dr Cobbold exhibited to
the Pathological Society of London a specimen of crested tapeworm which
was discovered in the museum of Middlesex Hospital, and to which he
proposed to give the name _Tænia lophosoma_ (λόφος, crest; σῶμα, body).
The reproductive papillæ were all on one side of the chain of segments,
a peculiarity which entirely distinguished it from the Cape of Good
Hope variety of Küchenmeister. The head of the creature was wanting. It
will thus be seen that my specimen does not correspond with either of
these in the situation of the genital aperture. Here it is placed in
the crest itself, and not unilaterally, as in Dr Cobbold’s specimen, or
alternately, as in Küchenmeister’s. It further differs from the Cape
variety in the more moderate dimensions of its proglottides. I have
adopted, however, the name suggested by Dr Cobbold in the communication
referred to, inasmuch as it sufficiently indicates the principal
distinguishing feature of the specimen. I may mention that Dr Cobbold
saw the specimen during his visit to Manchester, and that he regarded it
as a most remarkable and unique abnormality.”

Further, in connection with abnormal cestodes, I may observe that
Weinland’s case of a triple-crowned Cysticercus does not stand alone,
since a similar specimen is, I believe, in the possession of the Rev.
W. Dallinger. This was removed from the human brain. Curious as this
subject is, I cannot dwell upon it. Not only are the mature tapeworms
and their Cysticerci liable to present monstrosities, but even also
their proscolices or six-hooked embryos. Thus, twelve hooks were
observed by Salzmann in the embryo of _T. elliptica_, and Heller also
figures two embryos of _T. mediocanellata_ (_T. saginata_, Gœze) with
numerous hooklets. Dujardin saw seven in a _Bothriocephalus_ embryo.
Occasionally there have been errors of interpretation made by observers.
Thus, Diesing has given beautiful figures of _Dibothrium hians_ in
such a way as to suggest different degrees of monstrosity affecting
the tail end of the strobile; but this splitting has clearly resulted
from injury. Thus also, when I removed five specimens of a new cestode
(_Diphyllobothrium stemmacephalum_) from the intestines of a porpoise,
one of them was cleft nearly half way up the strobile. This had been
done by the scissors employed in slitting up the gut; but owing to
perfect contraction of the incised edges, it was some time before I
discovered that the apparent monstrosity had been artificially produced.
Lastly, I may add that many of the older writers were well acquainted
with larval and other anomalies. Thus Rudolphi described a two-headed
Cysticercus from a Lemur, and also a double-headed _Tænia crassicollis_.
This worm had a tripartite body; as had likewise a _Tænia crassicollis_
of which he did not possess the head (_corpore prismatico_). Other
monstrosities were described and figured by Bremser and Creplin. Pallas
mentions a two-headed Tricuspidaria (_Triænophori nodulosi bicipites_),
and, as already stated at p. 97, a double-headed Cysticercus has been
obtained from the liver of a sheep.

Before quitting the _Tæniæ_ proper, I may observe that several other
species have been indicated, based on ovular and other insufficient
characters. To these belong Ransom’s supposed tapeworm, and also
Weinland’s _Tænia megaloön_.

BIBLIOGRAPHY (No. 18).--_Bonnet, C._, ‘Œuv. Compl.,’ tom vi, p.
191, 1791.--_Bremser_, Atlas, by Leblond, Pl. iv.--_Chaussat_,
‘Comptes Rendus,’ p. 20, 1850.--_Cobbold_, ‘Catalogue of the
specimens of Entozoa in the Museum of the Royal College of Surgeons
of England,’ Nos. 118-121, London, 1866.--_Idem_, ‘Worms,’ l. c.,
p. 78.--_Idem_, “On a Cysticercus from the Human Brain,” ‘Brit.
Assoc. Rep.,’ 1870.--_Creplin_, ‘Tænia Monstrum, &c.,’ Berlin,
1839.--_Cullingworth, C. J._, “Notes on a remarkable specimen of
Tapeworm (_Tænia lophosoma_, Cobbold),” ‘Med. Times and Gaz.,’ Dec.,
1873.--_Davaine_, ‘Les Cestoïdes,’ l. c., p. 570.--_Diesing_, ‘Zwanzig
Arten von Cephalocotyleen,’ figs. 1 and 2, taf. ii (aus dem xii, Bd.
d. denkschr. d. Math.-nat. Cl. d. k. Akad.), Wien, 1856.--_Dujardin_,
l. c., p. 619.--_Heller_, l. c., s. 600.--_Küchenmeister_, l. c., Eng.
edit., p. 139.--_Leuckart_, l. c., s. 303 and 465.--_Levacher_, ‘Journ.
l’Institut,’ p. 329, 1841.--_Pittard, S. R._, Remarks in his article
“Symmetry,” Todd’s ‘Cyclop.,’ vol. iv, p. 848, 1849-52, in which he
refers to a monstrous Bothriocephalus (_T. lata_) in the Hunterian
Museum, old ‘Catalogue of Nat. Hist.,’ pl. iv, p. 50, No. 205; see
also my ‘Catalogue,’ l. c., _supra_, No. 167.--_Ransom_, in Reynolds’
‘System of Medicine.’--_Rudolphi_, ‘Synops.,’ p. 545 and 598-9, with
fig. showing the heads of _Cystic. Simiæ_ (biceps), widely apart,
1819.--_Weinland_ (_T. megaloön_), in Zoolog. Garten, Frankf., 1861, s.
118.--_Idem_, ‘Essay,’ l. c., p. 11.

_Bothriocephalus latus_, Bremser.--This species, though seldom seen in
England, is sometimes brought hither by persons who have been residing
for a time in foreign countries. It is indigenous in Ireland, and,
though by no means common there, has been called the Irish Tapeworm. As
regards its distribution in Europe it is much more prevalent in some
districts than in others. On this point Leuckart remarks that “foremost
amongst these are the cantons of West Switzerland, with the adjacent
French districts. In Geneva, according to Odier, almost a fourth part of
all the inhabitants suffer from Bothriocephalus. It is also common in
the north-western and northern provinces of Russia, in Sweden, and in
Poland. In Holland and Belgium it is likewise found, but, on the whole,
not so frequently as in the first-named countries. Our German fatherland
also harbours them in some districts, especially in eastern Prussia and
Pomerania, and there have appeared cases in other places, as in Rhenish
Hesse, Hamburg, and even in Berlin; these being apparently spontaneous
instances.”

Unlike the ordinary tapeworms, the segments of the broad tapeworm do
not individually separate so as to become independent organisms, a
circumstance which is highly favorable to the bearer. Its remarkable
breadth, and the extremely numerous and closely-packed proglottides,
impart a sufficiently distinctive character; but this parasite may
be more fully characterised as the largest human cestode at present
known, attaining a length of more than twenty-five feet, and sometimes
measuring nearly an inch in breadth; the so-called head 1/25″ in width,
bluntly pointed at the tip, much elongated or club-shaped, slightly
flattened from behind forwards, and furnished with two laterally
disposed slit-like fossæ or grooves, but destitute of any armature:
anterior or sexually-immature segments of the body extremely narrow,
enlarging in a very gradual manner from above downwards; joints of the
lower half of the body gradually decreasing in width, but enlarging in
depth; sexually-mature segments usually about 1/8 of an inch in depth,
but those near the caudal extremity frequently 1/4″, and quadrate in
form; body flattened, but not so uniformly as obtains in the ordinary
tapeworms, being rather thicker near the central line; total number
of joints estimated at nearly 4000, the first sexually-mature ones
being somewhere about the six hundredth from the head; reproductive
orifices at the central line, towards the upper part of the segment at
the ventral aspect, the vaginal aperture being immediately below the
male outlet, and both openings surrounded by papillæform eminences;
uterus consisting of a single tube, often seen regularly folded upon
itself, forming an opaque, conspicuous, centrally-situated rosette; eggs
oval, measuring 1/350″ in length by 1/550″ in breadth, having three
shell-coverings, and a lid-like operculum at one end, as occurs in the
fluke-worms. Owing to the dark color of the egg shells, the uterine
rosette is readily seen by the naked eye as a conspicuous deep brown
spot at the centre of each successive segment.

[Illustration: FIG. 25.--Head and neck of _Bothriocephalus latus_. _a_,
Front view. The smaller figure represents the head as seen from the
side. After Knoch.]

The source and development of this parasite are points of considerable
interest. The eggs are of comparatively large size, and after expulsion
and immersion in water they give passage to beautifully ciliated
embryos, which latter produce larvæ furnished with a boring apparatus.
These larvæ resemble the six-hooked embryos of other tapeworms. In what
animals the larvæ subsequently develop themselves is not ascertained
with certainty, but it is probable that persons become infested by
eating imperfectly cooked fresh-water fish. Leuckart has suggested that
the intermediary bearers are species of the salmon and trout family. Dr
Knoch, of Petersburg, thought that there was no need of the intermediate
host. He believed that he had succeeded in rearing young broad tapeworms
in the intestines of dogs. It was Leuckart who first explained the
source of Knoch’s errors of interpretation. Although Knoch administered
eggs of _Bothriocephalus latus_ to dogs, and afterwards found young
tapeworms of the species in question in the intestines of the dogs,
it did not logically follow that any genetic relation (as between
the egg-contents and the adult worms) had been thereby established.
The circumstance that ripe ova of the Bothriocephalus always contain
six-hooked embryos, must alone imply that an intermediate host is
necessary for the formation of Cysticerci or measles. If the broad
tapeworm could be reared in a direct manner by the administration of
Bothriocephalus eggs, there would be no need for the presence of boring
hooklets in the proscolex. These are necessary for invading the flesh of
some intermediate host.

[Illustration: FIG. 26.--Proscolex, or six-hooked embryo of
_Bothriocephalus_, escaping from its ciliated covering. After Leuckart.]

Dr Fock, of Utrecht, has sent me particulars of an interesting case, and
he suggests that infection comes from the little river bleak (_Leuciscus
alburnus_). Writing from Utrecht in December, 1877, Dr Fock, after
referring to a former case, goes on to say:--“Permettez moi, cher
confrère, que je rappelle à votre souvenir que vous avez eu l’obligeance
de communiquer au public une observation, de ma main, sur un cas très
rare de ver rubanaire, d’un Bothriocephale, chez une petite fille juive.
Malheureusement je n’ai pu en donner de plus amples détails, parce que
cette enfant n’a plus, depuis ce temps-là, rendu la plus petite parcelle
de ver. Il y a maintenant quinze mois, et voilà que de nouveau un cas
pareil se présente. Une femme mariée, frisonne, et, cette fois-ci
encore, juive, s’est adressée à moi pour la débarasser de son ver. Elle
me disait avoir rendu, il y a quelque temps, des fragments, ou plutôt un
fragment de la longueur d’un mêtre, d’un ver solitaire, pour lequel
elle avait été traitée, sans succès, par son médecin ordinaire. A cause
de cela elle s’adressa à moi, et je lui ai repondu qu’elle devrait
revenir la première fois qu’elle rendrait de nouveau, spontanément, un
nouveau fragment. Après un mois d’intervalle elle est revenue en me
montrant un fragment de la longueur d’un demi-mêtre qu’elle venait de
rendre spontanément, après avoir jeûni par précepte réligieuse, et deux
jours après cela, traitée par l’écorce de grenadier, elle a rendu un
Bothriocephale parfaitement conditionné en entier.

“Ce cas me semble assez intéressant pour être communiqué de nouveau,
d’abord parce que jusqu’ici personne n’a pu dire par quel chemin a pu
s’introduire un tel helminthe, et ensuite parce que ce chemin doit se
présenter bien rarement dans nos contrées (ou en Angleterre) puisque
dans le courant d’une trentaine d’années ayant rencontré des centaines
de tænias, ce cas-ci est seulement le second dont je suis gratifié. Il
me semble digne de réflexion que ce cas-ci se présente cette fois-ci
de nouveau chez une juive. Est ce cas-ci fortuit, ou bien y-a-t’il un
lien de causalité entre ce ver rare et le genre de nourriture ou de
boisson de ces bonnes gens? La dame me recontait que, en Frise, il
y a un poisson très recherché qui s’appelle en Hollandais blèck, en
Anglais blay ou bleak, et dont ils sont très friands, dans lequel, ils
rencontrent très souvent un très grand ver rubanaire. Une autre personne
me disait avoir été à table chez un ami, qui ne sachant probablement
ce qu’il mangeait, savoura avec beaucoup de délice cette friandise
dégoutante.”

After describing the specimen, Dr Fock concludes his remarks with a
suggestion as to the possibility of introducing tapeworm into the
human body by potable water, into which Cysticerci have accidentally
found their way. Dr Fock remarks:--“J’ajoute une réflexion par rapport
à la provenance des autres tænias, qui jusqu’ici sont introduits par
l’usage de la viande non assez cuite ou rôtie, ou saignante; mais, ne
se pourrait-il pas que des débris de la chair d’un animal ladre fussent
introduits fortuitement dans l’eau, par example, d’un fossé, et que
celle-ci employée comme boisson contint des Cysticerques et par ainsi
aussi une cause de Tænia? Ce n’est qu’une conjecture que je propose en
terminant cet article.”

Although I cannot at all agree with Dr Fock in regarding water as a
source of infection in the manner he indicates, yet the still more
recently expressed opinions of MM. Bertolus and Duchamp, based on
experimental researches, render it tolerably certain that Leuckart’s
original surmise was correct, and that we must look to freshwater fishes
for the larvæ of the broad tapeworm. In the section of this work devoted
to the parasites of fishes I shall make particular allusion to the
experiences of Dr Bertolus; but as confirming the view of Leuckart I may
here observe, that Bertolus has almost proved that the so-called _Ligula
nodosa_ infesting the common trout is merely a sexually incomplete
example of _Bothriocephalus latus_. The bleak (_Leuciscus alburnus_)
shares with other freshwater fishes the privilege of harbouring a
species of _Ligula (L. digramma)_; but whether this form bears any
genetic relation to our human _Bothriocephalus latus_ can only be
determined by actual experiment. If, as Duchamp and others have either
indicated or implied, _Ligula alburni_ is a synonym of the bleak’s
cestode in question, then it is evident that the sexually mature form of
the _Ligula_ of the bleak is the well-known _L. simplicissima_ of many
water birds and of a few other avian species. Probably the bleak-eaters
of Holland consume many kinds of freshwater fishes, including various
species of the salmon and trout family.

[Illustration: FIG. 27.--Strobile of _Bothriocephalus cordatus_. After
Leuckart.]

The symptoms occasioned by _Bothriocephalus latus_ do not differ
materially from those produced by other tapeworms. According to Odier,
as quoted by Davaine, there is not unfrequently a tumid condition of
the abdomen, with sickness, giddiness, and various hysterical phenomena
occurring at night. Pain in the region of the heart, palpitations, and
faintness are also mentioned.

As already hinted, this cestode is very liable to present abnormalities
of structure, the proglottides frequently displaying double sexual
orifices, with corresponding duplication of the reproductive organs
internally. For details respecting the anatomy of _Bothriocephalus_
I must refer to the works of Küchenmeister and Leuckart; and more
particularly to the memoir of Drs F. Sömmer and L. Landois, who have
supplemented the previous researches of von Siebold, Leuckart, Böttcher,
Stieda and others by beautiful investigations of their own. In the pages
of ‘Nature,’ for 1872, I gave a _résumé_ of Sömmer’s memoir, which will
be found quoted below.

_Bothriocephalus cordatus_, Leuckart.--This species is identical with
a worm long ago described by Pallas and Linneus. At present it is only
known to infest the residents of North Greenland, but it is probably
distributed throughout the north generally. It attains the length
of about one foot, and has a small heart-shaped head, whose apex is
directed forwards. The neck is so obscure that it may be said to be
altogether wanting, the segmentation of the body being well marked
immediately below the head. Though so small a species, Leuckart, who
first described it, counted between six and seven hundred joints. As
in the broad tapeworm, the reproductive orifices are serially disposed
along the centre of the ventral line, but a close inspection shows that
the folds of the egg-bearing organ are comparatively more numerous. This
worm does not appear to be a frequent resident in the human body, though
it is by no means uncommon in the dog. Possibly it may yet be found in
the inhabitants of some of our northern and western isles.

[Illustration: FIG. 28.--Head of _Bothriocephalus cristatus_, viewed from
the front. After Davaine.]

_Bothriocephalus cristatus_, Davaine.--This cestode measures between
nine and ten feet in length, and is characterised by the presence of two
remarkable prominences, together forming a sort of rostellum or crest
which is covered by numerous minute papillæ. The full-grown segments
are less than half an inch in breadth; the body of the parasite being
narrower than that of the broad species. The original description of
the parasite by Davaine is based on two specimens, one of which, quite
perfect, was obtained from a child five years old, under Dr Féréol’s
care at Paris. The other was passed spontaneously by an adult residing
at Haute-Saône. I have here copied one of Davaine’s original figures of
the head of the worm.

BIBLIOGRAPHY (No. 19).--_Bertolus_, “Mém. sur le development du
_Dibothrium latum_” (in Appendix to Duchamp’s work, see Bibliog. No.
59).--_Blanchard_, “Recherches, &c.,” ‘Ann. des Sci. Nat.,’ ser. 3,
Zool., Pl. 11, 12, 1848.--_Böttcher_, “Studien ueber den Bau des _Both.
latus_,” ‘Virchow’s Archiv,’ s. 97 _et seq_, 1864.--_Bremser_, l. c.,
Bibl. No. 1, s. 88, 1824.--_Chiaje_, ‘Compendio, &c.,’ Tab. iii, figs.
1-5, 1833.--_Cobbold_, ‘Entoz.,’ p. 289, 1864.--_Idem_, “Remarks on
the Broad Tapeworm” (with a letter from Dr Fock), the ‘Veterinarian,’
July, 1878.--_Creplin_, in Ersch and Gruber’s ‘Encyclop.,’ 1839,
p. 296.--_Davaine_, ‘Traité,’ l. c., 1860; 2nd edit. (_passim_),
1877.--_Idem_, art. ‘Les Cestoïdes,’ l. c., Bibl. No. 2, p. 580-591,
1876.--_Dujardin_, l. c., Bibl. No. 1, p. 612, 1845.--_Eschricht,
D. F._, ‘Anat-physiol. Untersuchungen ueber die Bothriocephalen,’
Breslau, 1840.--_Fock_ (see Cobbold).--_Heller_, ‘Darmschmarotzer,’
l. c., s. 606, 1876.--_Knoch_, ‘Petersburger Med. Zeitschrift,’
1861.--_Idem_, ‘Die Naturgeschichte des breiten Bandwurms (_B. latus_,
auct.),’ St Petersburg, 1862.--_Küchenmeister_, ‘Ueber cestoden,’ l.
c., 1853.--_Leuckart_, ‘Die Blasen Bandwürmer,’ 1856.--_Idem_, ‘Die
mensch. Par.,’ Bd. i, s. 414-448, und 757, 1863; and Bd. ii, s. 866,
1876.--_Owen_, Todd’s ‘Cyclop.,’ 1837.--_Sömmer_ und _Landois_, aus
Sieb. und Köll. Zeitschr., ‘Beiträge zur Anatomie der Plattwürmer,’
Leipsig, 1872; see also the _résumé_ in ‘Nature’ for Aug., 1872, p.
278.--_Wawruch_, ‘Pract. Monograph. d. Bandwürm-Krankheit,’ 1844, s. 33.

_Echinococcus hominis_ (the common hydatid).--This larval entozoon has
acquired various names according to the kind of bearer in which it
happens to have been found; but all the true hydatids or acephalocysts,
whether infesting man or animals, are referable to one and the same
species of parasite. They have been termed _Echinococcus hominis_,
_E. veterinorum_, _E. polymorphus_, _E. exogena_, _E. endogena_, _E.
multilocularis_, according to circumstances. All of them represent a
juvenile stage of the _Tænia echinococcus_ or hydatid-forming tapeworm
which infests the dog and wolf. Experimental proof of this fact has been
furnished by Von Siebold (1852), Haubner, Leuckart, Küchenmeister, Van
Beneden, Naunyn, Nettleship, Krabbe, and others.

The first successful rearing of _Tæniæ_ with human hydatids was
accomplished by Naunyn (1864), his results being subsequently
verified by Krabbe and Finsen (1865). Zenker, Ercolani, and several
others, including myself, also conducted feeding experiments with
human hydatids which were attended with negative results. In the
case of one of my experimental dogs the animal was liberated by an
ill-disposed person before I had opportunity to destroy it. As the
experiment was carefully conducted, the animal may have proved a
source of fresh echinococcus-infection. Mr E. Nettleship’s eminently
successful experiment was made with hydatids obtained from a sheep. The
converse experiment, namely, that of rearing hydatids with the mature
proglottides of _Tænia echinococcus_ administered to animals, has been
performed most successfully by Leuckart, and by Krabbe and Finsen; by
the former in the pig, by the latter in a lamb, with tapeworms that had
also been reared by experiment. Zenker, later on, reared the _Tænia_
from hydatids obtained from an ox.

[Illustration: FIG. 29.--_Tænia echinococcus_ Strobile. Mag. 30 diam.
Original.]

The sexually mature _Tænia echinococcus_ may, for the purposes of
diagnosis, be characterised as a remarkably small cestode, seldom
reaching the fourth of an inch in length and developing only four
segments, including that of the head; cephalic extremity capped by
a pointed rostellum, armed with a double crown of comparatively
large-rooted hooks, from thirty to forty in number; the four suckers
prominent, and succeeded by an elongation of the segment forming the
so-called neck; final segment, when sexually mature, equalling in length
the three anterior ones; reproductive papilla at the margin of the
proglottis rather below the central line; proscolex or embryo giving
rise to the formation of large proliferous vesicles, within which the
scolices or echinococcus-heads are developed by gemmation.

When an animal is fed with the mature proglottides of _Tænia
echinococcus_ the earliest changes that take place are the same as
obtain in other cestodes. The segments are digested; the shells of the
ova are dissolved; the six-hooked embryos escape. The embryos bore
their way into the organs of circulation, and thence they transfer
themselves to the different organs of the host; being especially
liable to take up their abode in the lungs and liver. Having arrived
at this, their resting stage, the embryos are next metamorphosed into
hydatids. According to Leuckart’s investigations the juvenile hydatid
is spherical at the earliest stages; being surrounded by a capsule of
connective tissue formed from the organs of the host. After removal
from its capsular covering, the vesicle consists of a thick laminated
membrane, forming the so-called cuticular layer, and a central granular
mass, which subsequently becomes enveloped by a delicate granular
membrane. At the fourth week the echinococcus capsule measures about
1/25″ in diameter, its contained hydatid being little more than half
this size. Its future growth is by no means rapid, seeing that at the
eighth week the hydatid has attained only the 1/15″ in diameter. At
this period the central granular mass develops a number of nucleated
cells on the inner surface of the so-called cuticle. These cells, which
at first are rounded or oval, become angular or elongated in various
directions, and even distinctly stellate; and in this way a new membrane
is formed, constituting the so-called inner membrane or granular
layer. The intermediate stages between this condition and that of the
fully-formed echinococcus hydatid have not been satisfactorily traced in
detail; nevertheless, Krabbe and Finsen’s experiment on a lamb showed
that within a period of little more than three months well-developed
echinococcus-heads may be formed in the interior of the vesicles. It
is thus clear that the production of scolices immediately follows the
formation of the granular layer, and this is succeeded, though not
invariably, by the formation of daughter- and grand-daughter-vesicles,
which are sometimes termed “nurses.” These latter may be developed
exogenously or endogenously.

The appearance of hydatids varies very much according to their mode
of formation, to the kind of host in which they are present, and to
the character of the organs in which they happen to take up their
residence. The so-called exogenous type occurs sparingly in man, whilst
the endogenous type is very abundant. The peculiar form known as the
multilocular echinococcus is probably a mere variety of the exogenous
type. The exogenous and endogenous hydatids may coexist in the same
bearer. In the lower animals we commonly find the organs of the body
occupied by numerous lobulated cysts, varying in size from a walnut to
a goose’s egg, but sometimes rather larger. They are rarely solitary,
being particularly liable to occupy both the liver and lungs in the same
animal. The viscera are sometimes crowded with cysts. The hydatids do
not usually protrude much beyond the surface of the infested organ, but
lie imbedded within its parenchymatous substance.

The multilocular variety was first described by Virchow. In reference to
it Leuckart writes as follows:

“Hitherto we know this growth only from the liver, in which it forms a
firm, solid, and tolerably rounded mass of the size of the fist or even
of a child’s head. At first sight it looks more like a pseudoplasm than
a living animal parasite. If you cut through the tumour, you recognise
in its interior numerous small caverns, mostly of irregular shape, and
separated from one another by bundles of connective tissue, more or less
thick, and including a tolerably transparent jelly-like substance. In
the intervening stroma a blood-vessel or a collapsed bile-duct runs here
and there; but there is nowhere any trace of true liver substance. The
outer boundaries of the tumour are in most cases pretty well defined,
so that the attempt to cut these growths out is not difficult. In
particular spots, especially at the surface, one sometimes sees white,
moniliform, jointed lines passing off from the tumour, and even thicker
terminations which, perhaps, expand in the neighbouring liver-parenchyme
into new (multilocular) groups of different size. In one case, recorded
by Virchow, the growth extended, together with Glisson’s capsule, a
long way towards the intestine.” To this description it may be added,
that the growth on section presents an appearance not altogether unlike
alveolar colloid, having, in point of fact, been confounded with that
pathological product, with which, however, as stated by Virchow, it has
nothing in common. This is proved not only by the occurrence of the
pathological features above mentioned, but also, more particularly,
by the well-ascertained presence of echinococcus-heads in most of the
so-called alveoli. Several hypotheses have been broached with the view
of explaining the mode in which these multilocular hydatid growths are
formed. Virchow thought that the echinococcus vesicles were primarily
formed in the lymphatic vessels, whilst Schröder van der Kolk supposed
that they originally took up their abode in the biliary ducts. Although,
thanks to the courtesy of Professor Arnold Heller in giving me a
specimen, I have been enabled to confirm much that has been written
in respect of the morbid appearances, I can add nothing towards the
solution of the difficulty in question. Until lately it was supposed
that the multilocular variety of hydatids only existed in man, but
Professor Böllinger has encountered it in the liver of a calf.

[Illustration: FIG. 30.--Ectocyst, endocyst, and brood capsule of
Echinococcus. From a Zebra. After Huxley.]

Selecting any ordinary fresh example of the exogenous kind, and laying
the tumour open with a scalpel, we notice in the first instance an
escape of a clear transparent, amber-coloured fluid. This previously
caused the distension of the sac. If the tumour is large, this
escape will probably be followed by a falling in, as it were, of the
gelatiniform hydatid membrane, in which case the inner wall of the
external adventitious investment or true fibrous cyst will be laid
bare. If the hydatid be next withdrawn from the cyst, it will be seen
to display a peculiar tremulous motion, at the same time coiling upon
itself wherever there is a free-cut margin. Further examination of
portions of the hydatid will show that we have two distinct membranes;
an outer, thick, laminated, homogeneous elastic layer (the _ectocyst_
of Huxley), and an internal, thin, soft, granulated, comparatively
inelastic layer--the _endocyst_ of the same author. The terms are
convenient. The ectocyst is structureless, consisting of a substance
closely allied to chitine. For this and other reasons it has been called
the cuticular layer, but the endocyst is the essential vital part of the
animal, representing a huge compound caudal vesicle. In an hydatid from
the zebra, Huxley found that the endocyst was “not more than 1/2000th of
an inch in thickness, being composed of very delicate cells of 1/2000″
to 1/5000″ in diameter, without obvious nuclei; but often containing
clear, strongly refracting corpuscles, generally a single one only in a
cell.” Prof. Huxley adds: “These corpuscles appear to be solid, but by
the action of dilute acetic acid the interior generally clears up very
rapidly, and a hollow vesicle is left of the same size as the original
corpuscle. No gas is developed during this process, and sometimes the
corpuscles are not acted upon at all by the acid, appearing then to
be of a fatty nature. A strong solution of caustic ammonia produces a
concentrically laminated or fissured appearance in them. Under pressure
and with commencing putrefaction a number of them sometimes flow
together into an irregular or rounded mass.”

The precise mode of development of the echinococcus-heads or scolices
has been a subject of lengthened discussion between Leuckart and
Naunyn. According to Leuckart the earliest indication of the scolex
consists of a slight papillary eminence on the inner surface of the
granular endocyst. After a short period this prominence displays in its
interior a vacuole-like cavity, the latter being occupied, however,
with a clear limpid fluid. Its margins become more and more clearly
defined, until the cavity is by and by seen to be lined with a distinct
cuticular membrane. The papilla increasing in size, becomes at first
elongated or oval, eventually scoleciform, or even, perhaps, a true
echinococcus-head. Thus far the description bears out, in a measure,
the theoretical notions entertained by the older authors; but the
developmental process does not stop here. The scolex-development has now
to sacrifice itself by developing in its interior a brood of scolices
or echinococcus-heads. In other words, it becomes transformed into the
so-called brood-capsules of Leuckart and other authors. These structures
were previously well known to Professors Erasmus Wilson and George
Busk. Mr Wilson spoke of the capsule as “_a delicately thin proper
membrane_, by which the Echinococci are connected with the internal
membrane of the acephalocyst” (‘Med.-Chir. Trans.,’ 1845, vol. xxviii,
p. 21). Mr Busk described the echinococcus-heads as “attached to a
common central mass by short pedicles, which appear to be composed of a
substance more coarsely granular, by far, than that of which the laminæ
of the cyst are formed. This granular matter is prolonged beyond the
mass of Echinococci into a short pedicle common to the whole, and by
which the granulation is attached to the interior of the hydatid cyst.”
What Mr Busk here describes as a granulation can only be equivalent to
the brood-capsule and its entire contents, but he elsewhere speaks of
the capsule itself as a “delicate membranous envelope.” It should be
borne in mind that Busk’s paper was communicated to the Microscopical
Society so early as the 13th Nov., 1844; being published in the
‘Transactions’ for that year.

[Illustration: FIG. 31.--Group of Echinococcus-heads, from an hydatid
found in the liver of a sheep. Magnified about 25 diameters. From a
drawing by Professor Busk.]

[Illustration: FIG. 32.--Three brood-capsules, containing
Echinococcus-heads. Magnified 76 diameters. After Professor Erasmus
Wilson.]

In the completely developed state the echinococcus-heads exhibit
somewhat variable characters as to size and form, the latter differences
being, for the most part, dependent upon their degree of contraction
and vitality. In the perfect condition they vary from the 1/60″ to the
1/100″ in diameter, being usually about the 1/80″. They are solid, and
when stretched out exhibit an hour-glass-like constriction at the centre
of the body, which divides the scolex into an anterior part supporting
the rostellum and suckers, and a posterior part which has been compared
to the caudal vesicle of ordinary Cysticerci. The rostellum supports a
double crown of hooks, but the disparity of the two series is scarcely
sufficiently marked to render their distinction obvious. The hooks of
the smaller row vary in size from 1/1040″ to 1/830″ of an inch, whilst
those of the larger series are from 1/830 to 1/555″. In all instances
the root-processes are incompletely developed, and consequently vary
in thickness. They are, as Leuckart also has stated, apt to exhibit
abnormalities.

[Illustration: FIG. 33.--Separate _scolex_, or echinococcus-head.
Magnified 500 diameters. After Huxley.]

In regard to the development of the echinococcus-heads it further
remains for me to observe that a distinct water-vascular system is
recognisable in the scolices. By the intervention of the pedicle of
the scolex this system is connected with the brood-capsule, and also
with the vessels of the maternal endocyst. In the scolex there exists
a circular channel immediately below the rostellum, and this ring, on
either side, gives off two vessels which pass downwards in a tortuous
manner, internally, until they arrive at the pedicle where they unite to
form two channels, which latter are continued into the vascular system
of the maternal endocyst. In the retracted condition their position, of
course, becomes very much altered, and they form loops on either side
of the central line which marks the space leading down to the inverted
head. Neither Prof. Huxley nor myself have seen these vessels, which
Leuckart observed in the scolex itself, but Huxley discerned some
apparently loose cilia in the granular parenchyma of the body; their
longitudinal measurement being about the 1/3500 of an inch.

[Illustration: FIG. 34.--An Echinococcus brood-capsule (flattened by
pressure). Magnified about 120 diameters. From a drawing by Professor
Busk.]

As regards the production of “nurses” by the phenomenon of
proliferation, I can only remark that the endocyst is primarily
concerned. The secondary and tertiary vesicles must be regarded as so
many special bud-developments which, instead of becoming brood-capsules,
become daughter-vesicles and grand-daughter vesicles, constantly
developing in their interior secondary and tertiary brood-capsules and
scolices, but sometimes, it would appear, developing neither the one
nor the other. This is the view of Naunyn, which is somewhat opposed by
Leuckart, who holds that the vesicles ordinarily arise from within the
layers of the ectocyst. Speaking of these daughter-hydatids Leuckart
remarks that “Naunyn denies that they take their origin between the
lamellæ of the mother bladder--a fact, however, which, in agreement
with Kuhl and Davaine, I have seen more than once and have followed
out step by step.” For my own part I incline to the belief that the
process as observed by Leuckart is exceptional, and that under ordinary
circumstances it occurs as Naunyn has described it. Thus the long and
short of the whole matter appears to be that the endocyst is capable of
forming solitary scolices. Some of the scolices become differentiated to
form brood-capsules, a portion of whose individual echinococcus-heads
may, in their turn, become secondary brood-capsules, whilst others
fail to become either scolices or brood-capsules. It accords with
our knowledge of the general plan of development to believe that the
daughter and grand-daughter hydatids are likewise peculiarly modified
scolices. They are, in short, buds of the endocyst.

The distribution of hydatids throughout the organs of the bearer, and
their prevalence in particular countries, has especially engaged my
attention. I have personally examined upwards of a thousand preparations
of entozoa in our public collections; and of these, 788 are preserved
in the anatomical and pathological museums of the metropolis. By
this inspection I have obtained a tolerably accurate knowledge of
the pathology, localisation and effects produced by the presence of
bladder-worms in at least 200 unpublished cases of hydatid disease. Most
of our museums exhibit one or more specimens that are unique. After
making certain necessary deductions, I find that I have 192 new cases to
add to the 135 cases of hydatid disease that I had previously recorded,
affording a total of 327 cases available for statistical purposes. If
an analysis of these cases be made and compared with the statistics
furnished by Davaine, and if the whole be reduced to the lowest number
of practically available terms, we at length obtain a result which,
although it may be only approximatively correct, is nevertheless of much
practical value and significance. The statistics in question stand as
follows:

  +-----------------------------+----------+-----------+--------+
  |       Organs affected.      | Davaine. |  Cobbold. | Total. |
  +-----------------------------+----------+-----------+--------+
  | Liver                       |   165    |    161    |  326   |
  | Abdomen, including spleen   |    26    |     45    |   71   |
  | Lungs                       |    40    |     22    |   62   |
  | Kidney and bladder          |    30    |     23    |   53   |
  | Brain                       |    20    |     22    |   42   |
  | Bones                       |    17    |     16    |   33   |
  | Heart and pulmonary vessels |    12    |     13    |   25   |
  | Miscellaneous               |    63    |     25    |   88   |
  +-----------------------------+----------+-----------+--------+
  |            Total            |   373    |    327    |  700   |
  +-----------------------------+----------+-----------+--------+

In the main Davaine’s table and my own show a remarkable correspondency,
as is seen in the numbers referring to hydatids of the liver, heart, and
bones respectively. Where our results do not correspond the explanation
of the discrepancy is sufficiently simple. The abdominal cases here
credited as such in Davaine’s table are placed by him under _pelvis_,
whilst the abdominal cases in my own table not only include the pelvic
hydatids, but also two _spleen_ cases, and nineteen others from the
peritoneum and intestines.

As the facts here stand, the liver cases comprise nearly 46-1/2 per
cent. In a large number of cases the entozoon has taken up its abode
in organs of vital importance. If statisticians and officers of health
would obtain an adequate conception of the fatal capabilities of
parasites, they should consider these data. In 6 per cent. of all these
cases the bladder worm has found its way into the brain, and of course
proved fatal to the bearers; in about 3-1/2 per cent. more they took
up their residence in the heart, also proving fatal; whilst of all
the other cases put together I reckon that not less than 15 per cent.
were concerned in bringing about the death of their hosts. I probably
underrate the fatal capabilities of echinococcus disease when I express
the conviction that hydatids prove fatal to 25 per cent. of all their
human victims.

The recently published analysis of 983 cases by Dr Albert Neisser
affords similar results. Of these, 451 were referable to the liver, or
45·765 per cent. The other cases, reduced as above, show in the main a
similar correspondency.

It may be asked if these facts afford us any assistance in determining
the amount of injury that we, as a people, sustain either directly or
indirectly from hydatids. On carefully reviewing all the data before me,
I may say that it is difficult to draw very precise conclusions; albeit
it is not mere guess-work when I assert that in the United Kingdom
several hundred human deaths occur annually from this cause. In some
other countries the proportion is far greater; the oft-quoted case of
Iceland, where the disorder is fatally endemic, still standing at the
head of the afflicted territories.

Our Australian colonies are probably entitled to the next place of
distinction in this respect. We have strong and recent evidence of the
truth of this statement. Thus a writer in the ‘Australian Med. and Surg.
Review’ says: “This disease is becoming unpleasantly frequent, and
at present we have no reliable mode of treatment, either theoretical
or empirical.” Another writer observes (‘Melbourne Argus,’ May 18th,
1874), “Hydatid disease is endemic in this colony; and, though not so
constantly met with as in Iceland, we may probably claim the doubtful
honor of holding the second place in the list of countries so affected.”
In the ‘Argus’ for June 20th of the same year, another writer refers to
the frequent notices of cases of hydatids published in the various local
newspapers. A retired medical man, the late Mr J. P. Rowe, writing in
the ‘Melbourne Leader’ (Sept. 7th, 1872), incidentally remarked on the
“notable increase of hydatid disease in the human subject.” Again, still
more satisfactory evidence is afforded by a reviewer in the ‘Leader’
of the 31st January, 1874. Commenting on my manual, he not only takes
occasion to speak of the prevalence of hydatids generally, but also
supplies that kind of accurate statistical evidence of which we so much
stand in need. He gives the following table, showing the number of
_deaths_ from hydatids in Victoria for eleven years. It is instructive
in many ways.

  +------------------------------+--------+----------+--------+
  |            Years.            | Males. | Females. | Total. |
  +------------------------------+-------------------+--------+
  | 1862                         |    3   |     2    |    5   |
  | 1863                         |    3   |     2    |    5   |
  | 1864                         |    6   |     3    |    9   |
  | 1865                         |    9   |     6    |   15   |
  | 1866                         |   18   |     7    |   25   |
  | 1867                         |   13   |    12    |   25   |
  | 1868                         |   21   |    12    |   33   |
  | 1869                         |   12   |    10    |   22   |
  | 1870                         |   10   |     7    |   17   |
  | 1871                         |    6   |     9    |   15   |
  | 1872                         |   24   |     5    |   29   |
  +------------------------------+-------------------+--------+
  | Total deaths in eleven years |  125   |    75    |  200   |
  +------------------------------+--------+----------+--------+

To employ the writer’s own words, “this mortality gives only a faint
notion of the extreme prevalence of hydatids in Victoria, since numbers
of cases are cured by tapping, and otherwise by medical treatment, or
by spontaneous bursting of the cysts.” Hydatids are often found post
mortem where their presence has never been suspected during life. “To
meet with hydatids as a cause of deranged health is now a matter of
daily expectation with every medical practitioner.” Lastly, Dr Dougan
Bird, in his able brochure on ‘Hydatids of the Lung,’ fully confirms
these statements, remarking that the rich and poor of the Australian
metropolis suffer just as much from hydatids as do either the shepherds
of the western plains, or the miners of Ballarat and Sandhurst.

Such are the facts from Australia. As regards home evidence, so far
as I am aware, little or nothing has been done towards securing an
accurate estimate of the mortality in England from echinococcus disease.
The reports of the Registrar General give no sufficient sign. The
explanation is not far to seek, since for the most part hydatids are
either classed with diseases of the liver, or with those of the other
organs in which they happen to have been present.

One of the most valuable contributions to our knowledge of the
prevalence of hydatid disease affecting animals is that supplied by
Dr Cleghorn, from a statistical table constructed by the executive
commissariat officers stationed at Mooltan. The record in question shows
that out of 2109 slaughtered animals, no fewer than 899 were affected
with hydatid disease. This is equal to more than forty-two per cent. In
the majority of cases, both the lungs and liver were affected, cysts
were found 829 times in the liver and 726 times in the lungs. In a few
instances they were present in the kidneys, and also occasionally in the
spleen. The inference from all this is that in India, if not elsewhere,
the echinococcus disease is much less common in man than it is in
animals. The explanation is simple enough, since cattle have more ready
access to, and less scruple in partaking of filthy water and food in or
upon which the eggs of the _Tænia echinococcus_ abound.

Into purely professional questions connected with the treatment of the
echinococcus malady I do not here enter; nevertheless, in connection
with hygiene I may observe that the prevalence of hydatids in any
country is strictly dependent upon the habits of the people. The close
intimacy subsisting between the peasantry and their canine companions
is the primary source of the endemic; and where dogs are not kept, it
is well nigh impossible that the disease should be contracted. The fact
that every Icelandic peasant possesses, on an average, six dogs, and
that these dogs share the same dwelling (eating off the same plates and
enjoying many other privileges of intimate relationship) sufficiently
explains the frequency of hydatids in that country. According to Krabbe,
the sexually mature _Tæniæ_ occur in 28 p. c. of Icelandic dogs,
whereas in Copenhagen he found it twice only in 500 dogs examined. In
his work (quoted below, p. 58, or Fr. Edit., p. 60) Krabbe comments on
a sensational passage which, in my introductory treatise (p. 283), I
had quoted from a popular memoir by Leuckart (‘Unsere Zeit,’ s. 654,
1862). The practitioners whom we had spoken of as “quacks” are mostly
homœopaths; and it appears that even those who are not in any legal
sense professional men “treat their patients much in the same way as
ordinary medical men.” It simply comes to this, that, instead of _dog’s
excrement_ forming with the aforesaid “quacks” a conspicuous or common
remedy (as Leuckart’s description had led me to infer), this nasty drug
is now rarely administered, and by the grossly ignorant only.

Up to the present time no person has seen the _Tænia echinococcus_
in any English dog which has not been previously made the subject of
experiment, but considering the prevalence of hydatid disease amongst
us, there can be no doubt that English dogs are quite as much if not
more infested than continental ones. Probably, at least one per cent.
of our dogs harbour the mature tapeworm. Certainly a great deal of good
might accrue from the acquisition of more extended evidence respecting
the prevalence of this and other forms of entozoa infesting man and
animals in this country.

From Schleissner’s table it appears that hydatids are more frequent in
women than in men. Apparently, it is not so in Australia. As regards
Iceland the explanation must be sought for in the different habits of
life. No doubt, water used as drink by women is constantly obtained from
supplies in the immediate neighbourhood of dwellings, and in localities
to which dogs have continual access. The comparative rarity of the
echinococcus disease amongst sailors is not so much dependent upon the
circumstance that seamen’s diet usually consists of salted provisions,
as upon the fact that these men can seldom have opportunities of
procuring water from localities where dogs abound. In regard to water
drinking, there is ground for believing that the addition of a very
little alcohol is sufficient to destroy the six-hooked embryos of _Tænia
echinococcus_ whilst still _in ovo_; and there is no doubt that water
raised to a temperature of 212° Fahr. will always ensure the destruction
of the larvæ. Boiled water by itself is by no means palatable. The
reason why the upper classes comparatively seldom suffer from hydatids
may be attributed to the circumstance that those few who drink water
take the very proper precaution to see that it is either “pump” or fresh
spring water in which no living six-hooked embryos are likely to exist.
So far as hydatids are concerned, wine and beer drinking is preferable
to water-drinking; yet if water is carefully filtered no evil of the
parasitic kind can possibly result from its imbibition. An ordinary
charcoal filter will effectually prevent the passage of the ova, since
their diameter is nearly 1/370 of an inch.

From what has been stated it follows that personal and general
cleanliness are eminently serviceable as preventions against infection,
but to ensure perfect success other precautions must be exercised,
especially in relation to our contact with and management of dogs.
Leuckart puts this very clearly when he says:--“In order to escape the
dangers of infection, the dog must be watched, not only within the
house, but whilst he is outside of it. He must not be allowed to visit
either slaughter-houses or knackeries, and care must be taken that
neither the offals nor hydatids found in such places are accessible to
him. In this matter the sanitary inspector has many important duties
to perform. The carelessness with which these offals have hitherto
been disposed of, or even purposely given to the dog, must no longer
be permitted if the welfare of the digestive organs of mankind is to
be considered. What blessed results may follow from these precautions
may be readily gathered from the consideration of the fact that, at the
present time, almost the sixth part of all the inhabitants annually
dying in Iceland fall victims to the echinococcus epidemic” (l. c., s.
654). Similar measures had previously been recommended in less explicit
terms by Küchenmeister, who in effect remarked that the principal thing
was to ensure the destruction of the echinococcus vesicles. He also
recommended the expulsion and annihilation of the _Tænia echinococcus_.
In order to carry out this idea, it was suggested by Dr Leared that
every dog should be periodically physicked, and that all the excreta,
tapeworms included, should be buried at a considerable depth in the
soil. I advised, however, that in place of burying the excreta, _they
should, in all cases, be burnt._ I had, indeed, long previously urged
this measure (in a paper “on the _Sclerostoma_ causing the gape-disease
of fowls,” published in 1861), with the view of lessening the prevalence
of entozoa in general, whether of man or animals. The rule I suggested
stood as follows:--_All entozoa which are not preserved for scientific
investigation or experiment should be thoroughly destroyed by fire, when
practicable, and under no circumstances whatever should they be thrown
aside as harmless refuse._ As an additional security I recommended that
boiling hot water be occasionally thrown over the floor of all kennels
where dogs are kept. In this way not only would the escaped tapeworms be
effectually destroyed, but also their eggs and egg-contents, including
the six-hooked embryos. These measures were again advocated at the
Cambridge Meeting of the British Association in 1862, and also more
fully in a paper communicated to the Zoological Society, during the
autumn of the same year (‘Proceedings,’ vol. xxx, pt. 3, pp. 288, 315).

As the scope and tendency of this work preclude the textual admission
of clinical details, I must limit my remaining observations to the
pathology of hydatid disease. At very great labor, pursued at distant
intervals during a period of ten years, I sought to ascertain the
probable extent and fatality of this form of parasitism in England,
by going over such evidence as our pathological museums might supply.
Although, from a statistical point of view, the investigation could
hardly be expected to yield any very striking results; yet clinically
viewed the study was most instructive. The evidence which I thus
procured of numerous slow and painful deaths from echinococcus
disease, further stimulated me to place a summary of the facts on
record. Physicians, surgeons, scientific pathologists, and veterinary
practitioners are alike interested in the study of hydatid disease; and
I had not proceeded far in my careful investigation before it became
evident to me that very great practical results would ensue if, in this
kind of effort, the principle of division of labor had full play. At all
events, within these museums lie concealed a mass of pathological data
which, although well within reach, have not been utilised to the extent
they ought to have been.

As a student of parasites for some thirty years, I must without offence
be permitted to protest against the too frequent omission of parasites
in statistical evidence as a cause of mortality. From facts within my
own knowledge I can confidently assert that parasites in general, and
hydatids in particular, play a far more important part in the production
of disease and death than is commonly supposed. In saying thus much,
however, I am not insensible to the fact that, in recent times, new
methods of treatment combined with higher surgical skill, have greatly
tended to lessen the fatality of this affection. In this connection I
would especially refer to the recorded experiences of an able colonial
surgeon, Dr MacGillivray, as made known in the pages of the ‘Australian
Medical Journal.’ The able surgeon to the Bendigo Hospital, treated as
in-patients, from 1862 to 1872, inclusive, no fewer than seventy-four
cases of hydatid disease. He operated on fifty-eight of them. Two
patients were tapped for temporary relief (as they were dying of other
diseases); and of the remaining fifty-six only eleven died. No fewer
than forty-five were discharged _cured_--a fact redounding largely, I
should think, to the credit of Australian surgery.

In reference to museum evidence I have no hesitation in saying that the
pathological collections in the metropolis abound in rare and remarkable
illustrations of hydatid disease; most of the preparations being
practically known only to such few members of the medical profession
as have been at some time or other officially connected with the
museums. Not without justice, curators often complain that their work
and catalogues are turned to little account. As a former conservator of
the Edinburgh University Anatomical Museum (1851-56), and subsequently
as museum-curator at the Middlesex Hospital Medical College, I am
in a position to sympathise with them. Valuable, however, as the
catalogues are, it is often necessary to make a close inspection of the
preparations in order to arrive at a correct interpretation of the facts
presented.

Although the entozoal preparations in the museum attached to St
Bartholomew’s Hospital are, comparatively speaking, few in number, there
are some choice specimens of hydatid disease. There is a remarkable
case in which hydatids invaded the right half of the bones of the
pelvis; death resulting from suppurative inflammation of the cysts. This
patient, a woman, had also another hydatid cyst which was connected
with the ovary. Amongst the series contributed by Dr Farre, there is
a case represented where a large cyst containing numerous hydatids
“occupied the pelvis of an infant and produced retention of urine,”
which ultimately proved fatal. There are also several fine examples of
hydatids from the omentum (Dr Farre’s case), besides a good specimen
of acephalocysts connected with the vesiculæ seminales. There are two
other cases in which these larval entozoa were passed with the urine.
At the time when I made my inspection, the entire series represented
twenty-five separate cases, of which only one appears to have been
published in detail (Mr Evans’s case, ‘Medico-Chirurgical Transactions,’
1832). In addition to the above, I must not omit to particularise two
instructive preparations illustrative of a case in which an hydatid was
lodged in the right half of the cerebrum. This was from a girl in whom
head symptoms showed themselves a year before death, and in whom there
was partial hemiplegia of the left side. I may add that there is also in
the series a doubtfully genuine example of hydatids of the breast.

The collection in connection with the Westminster Hospital contains
several highly interesting specimens of entozoa (one of which I believe
to be altogether unique), but it is by no means rich in the matter
of hydatids. Out of a score of preparations of parasites of various
kinds, only four (apparently representing the same number of cases) are
hydatids, all of which appear to have been connected with the liver.
Two are certainly so, one of the latter (Mr Holthouse’s case) showing
calcareous degeneration.

The museum connected with St Mary’s Hospital Medical School, in addition
to several liver cases, contains one interesting example of hydatids
of the lung (Dr Chambers’s case), and also three valuable preparations
illustrating Mr Coulson’s remarkable case of hydatids affecting the
tibia. One of the preparations shows the bone itself, which was
eventually removed at the joint, the operation having been performed by
Mr Spencer Wells.

Here, perhaps, it will not be out of place to mention as a fact of
special clinical interest that I have encountered records of no fewer
than nine other similar cases where hydatids have taken up their abode
in the tibia, generally selecting the head or upper part of the bone.
Some of my notes have been mislaid, but, speaking from recollection, one
of the choicest specimens which I have examined is that contained in
the pathological museum of the Nottingham Hospital.

When I first went over the collection of the Middlesex Hospital Museum,
I found it to contain fifty-four preparations of entozoa, of which some
fourteen only were true hydatids, representing as many separate cases.
There are now upwards of a score of preparations of hydatids, several of
the cases having already had ample justice done to them by Dr Murchison
in his well-known memoir (‘Edinb. Med. Journ.,’ Dec., 1865). Amongst
the most interesting preparations I would especially call attention
to two fine and genuine specimens from the kidney, another very large
example of an hydatid situated between the bladder and rectum, a simple
acephalocyst removed from the orbit (Mr Hulke’s case), and the hydatid
removed from the axilla by the late Mr Charles Moore. There is a jar
containing hundreds of hydatids that were taken from the thoracic cavity
of a dissecting-room subject, who was reported to have died of phthisis;
and there is another preparation of an hydatid of the heart, which
also proved fatal, without there having been the slightest suspicion
entertained as to the true nature of the disease. For this fine
preparation the museum stands indebted to Dr Moxon, of Guy’s Hospital.
Several of the liver cases are particularly instructive; but amongst
the specimens presented by Mr Mitchell Henry is a small bottle full of
minute hydatid vesicles, all of which were removed from the interior of
the tibia. The history of this case has been lost; and, unfortunately,
the bone from which the parasites were taken does not appear to have
been preserved.

The museum connected with King’s College contains at least a dozen good
specimens of liver hydatids, several of the cases being of special
interest from a pathological point of view. There are two remarkably
fine examples of hydatids contributed by Dr Hooper, the parasites in
one case affecting the spleen, and in the other involving the ovary and
uterus. The spleen contained numerous encysted hydatids, whilst the
uterine organs exhibited “an immense collection” of the same growths. In
this place, also, I may refer to an hydatid-like entozoon, taken from a
cyst in the ovary of a female who had been under the care of Dr Johnson
(1860). It is, apparently, a genuine example of the slender-necked
hydatid (_Cysticercus tenuicollis_); and if so (as might be determined
by dissection), is, so far as I aware, the only specimen of the
kind in existence from the human bearer. There is a renal hydatid
(presented by Dr Pass, of Warwick) which was obtained from a lunatic,
its presence being “quite unsuspected during life.” Amongst the liver
cases (the majority of which are from Dr Hooper’s collection), there
is one enormous hydatid that was obtained from a young woman who had
died during a fit of laughter. The tumour had pushed the diaphragm up
to a level with the fourth rib; and it is stated that, on puncturing
the cyst, the fluid contents were ejected “in a jet nearly two feet
high.” There is one case represented where numerous hydatids were
expectorated after hepatitis, whence it was concluded that they were
originally connected with the liver. There is a large solitary hydatid
that was removed from a young female who died of phthisis, and in whom
the consequent swelling had formed in the neighbourhood of the navel.
Especially instructive, also, from a clinical point of view, is a case
of peritoneal hydatids where the tumours had been diagnosed to represent
a case of extra-uterine fœtation. It appears that there were two cysts,
one of them being connected with the uterus. Two of the enormous
hydatids taken from these cysts are preserved in the collection of the
Anatomy School of Oxford. Several of the preparations show to perfection
the stages of natural cure produced by calcareous degeneration; and
there is one liver showing three of these so-called ossified cysts. The
disease in this case proved fatal.

Most of the entozoa displayed in the Charing Cross Hospital Museum have
been contributed by Dr Wiltshire, the series being particularly strong
in tapeworms. There are four characteristic examples of hydatids of the
liver, representing as many separate cases. Two were from abscesses
of this organ. In one of these, Mr Canton’s case, the hydatid was, I
believe, expelled after operation; but in the other example (presented
by Mr Rose, of Swaffham) the parasite was evacuated from an abscess,
which burst of itself, externally.

In the museum at University College, I examined sixteen preparations
of hydatid disease, representing almost as many distinct cases. One
is a wax model. Eight of the specimens were from the liver, five
from the abdomen (including those of the omentum and mesentery), two
from the lungs, and one from the heart. The model displayed ordinary
hydatids of the liver bursting into the lungs. The mesenteric example
is particularly fine, whilst that from the omentum is undergoing
calcareous degeneration. Probably the most interesting of all is the
example showing an hydatid lodged in the septum of the heart. This
was from a middle-aged female, who died suddenly whilst pursuing her
ordinary domestic avocations.

The museum of the Royal College of Surgeons contains a fine collection
of parasites, its chief strength in this respect being due to the
special series of entozoa. Were visitors to judge by the contents of
the catalogue of this series (which I prepared some years ago at the
instance of the Council of the College), they might be led to suppose
that the hydatids were only feebly represented. Out of nine preparations
of hydatids in this section, only six have come from the human body.
However, scattered throughout the collection, I found that there were no
fewer than thirty-five preparations of hydatids belonging, apparently,
to as many as thirty separate cases. Omitting, for the present, all
mention of these derived from animals, I ascertained that, of the
thirty human cases, thirteen were referable to the liver, four to the
abdomen, three to the lungs (one of which was originally connected
with the liver), and two to the brain. Five were of uncertain seat.
With the abdominal cases we may also include one case of hydatids of
the spleen, and another where these organisms were found in the region
of the bladder. There is a characteristic breast case. One of the
original Hunterian cases (in which “a prodigious number of hydatids
were found in the sac of the liver and dispersed throughout the cavity
of the abdomen”) appears, though it is not expressly so stated in the
catalogue, to have been regarded as an ordinary example of abdominal
dropsy. In one of the three lung cases two small hydatids were
separately expectorated at an interval of about a month. This occurred
in a female.

I may here incidentally remark that many cases are on record where
abdominal hydatids have been overlooked, the patient being supposed to
be suffering from ascites. One such instance took place a few years ago
at the Middlesex Hospital. I well remember a similar case of supposed
hydrothorax, where the post-mortem examination revealed the presence
of immense numbers of these formations occupying the right side of the
chest. This case occurred at the Norfolk and Norwich Hospital, at the
time when I was a student there, some thirty-five years ago.

The pathological collection connected with St George’s Hospital
displays several good hydatid preparations, the entire series
representing at least twenty-two separate cases. Of these, fifteen are
referable to the liver, that is, if we include Dr Dickinson’s case,
already published, where hydatids were found within the hepatic duct.
There are two renal cases; also one from the brain (Dr Dickinson’s
case), and another where an hydatid was expectorated. Besides these,
there are three other highly characteristic examples of echinococcus
disease affecting the region of the neck, breast, and axilla
respectively.

The museum of the London Hospital Medical School contains a large
collection of parasites. Out of fifty-seven preparations of entozoa, I
found twenty-two referable to hydatids; and, so far as I could gather,
all of them belonged to different cases. Only one case seems to have
been published in detail. This, though a very old preparation, is a
fine example of an hydatid, nearly three inches in length, occupying
one of the cerebral hemispheres (‘Edinb. Med. Journ.,’ vol. xv). There
is a second brain case, where the vesicles were of small size, but very
numerous. Of the other twenty cases, fourteen belong to the liver, two
to the spleen, one to the lung, one to the uterus; one being a very
large hydatid of doubtful seat, and another being referable to the
lumbar region, where it formed a tumour containing “a large number of
small hydatids.” Amongst the more remarkable specimens is that described
in the MS. catalogue as “a true hydatid cyst developed in connection
with the broad ligament.” This preparation, unique of its kind, shows no
trace of the ovary, which, indeed, seems to have disappeared altogether.
One of the liver cases should rather be classed as abdominal, since the
large cyst is situated between the diaphragm and liver, pressing upon
the latter organ below and also upon the lung above, but apparently not
involving either of these viscera structurally. Another very striking
case is that in which there is an external opening communicating with
the cyst in the liver, and an internal opening through the diaphragm
communicating with the lungs and bronchial tubes. The patient had
actually coughed up liver hydatids by the mouth, and had passed others
through the right wall of his abdomen. There is another liver case in
which the hydatids, in place of escaping externally, had gained access
to the inferior cava; and if I understand the MS. record rightly, in the
same patient a second hydatid communicated with the portal vein, and
a third with the hepatic vein. Lastly, I must add that there is yet
another fine preparation of liver hydatids, occurring in a lad, nineteen
years of age. He had, it seems, met with “a slight accident, and died
with obscure head symptoms;” but the odd part of the case is that at the
post-mortem examination there was positively nothing found that could
explain the patient’s death. He was under the care of Mr Luke (1834).

Comparatively recently I inspected the collection at St Thomas’s
Hospital, which I found to be particularly rich in entozoa of various
kinds, especially tapeworms and hydatids. I encountered seventy-six
preparations of internal parasites; and of these, forty-two were of the
hydatid kind, representing at least thirty-three different cases. I
say “at least,” because it is often impossible to decide in instances
where no history of the specimens can be obtained. Thus, there are three
similar preparations of hydatids passed by the urethra, and, from their
appearance, I judge them to have come from one and the same patient; yet
there is no statement in the catalogue to that effect.

Of the thirty-three cases of hydatids represented in this museum, I
reckoned eighteen as referable to the liver, two to the brain, two to
the bones, two to the urinary organs, and one to the lung, spleen,
uterus, and soft parts of the thigh respectively. There are also three
that may be classed as peritoneal. There is another choice example in
which the disease cannot be referred to any particular organ. I allude
to Dr Peacock’s case, already published (‘Pathological Transactions,’
vol. xv), where the lungs, liver, heart, spleen, and some other organs,
were all occupied by hydatid formations. As an instance of extensive
visceral infection by Echinococci in the human subject, I believe this
case to be unique. The brain hydatids are particularly fine. In the
specimen presented by Mr Boot, of Lincoln, the hydatid, two inches
in diameter, is lodged in the anterior horn of the left ventricle.
One of the peritoneal cases is remarkable for the amount of forward
displacement of the pelvic viscera, caused by four or more hydatids,
each of them nearly as large as a cricket-ball. Amongst the abdominal
cases I have included a recent preparation, to which Mr Stewart has
called my attention. The hydatid in question, of the size of a large
lemon, existed near the fundus of the bladder, its walls being one
third of an inch in thickness, and forming an unusually firm tumour.
Of all the fine specimens of hydatids in the collection, however,
none have struck me so much as those affecting the bones. There is a
humerus, taken from a man thirty-four years of age, in which the shaft
is occupied throughout by small hydatids that have destroyed almost all
the cancellous structure; in some places, also, the absorption of the
cortical layer has gone on to such an extent as to have left little more
than the periosteum. Of course, the bone was at last fractured easily.
It is a beautiful specimen; and the existence of Echinococcus-heads
was proved by microscopic evidence. Scarcely less interesting are two
preparations illustrative of Mr Traver’s case of a man, thirty-eight
years of age, in whom numerous small hydatids occupied both the head of
the tibia and the lower end of the femur. Each set of parasites freely
communicated with the knee-joint, necessitating amputation of the limb.

The very large museum connected with Guy’s Hospital is rich in hydatids.
When, some time ago, I spent several days in going over the collection,
I examined seventy-six preparations, representing apparently seventy
separate cases of this affection. Amongst the noteworthy specimens one
lung hydatid was intimately associated with a thoracic aneurism, two
others being connected with the pleura; and of seven abdominal cases,
five were connected with the peritoneum, one with the mesocolon, and
one with the aorta. This last-mentioned instance occurred in a woman
of sixty years, who, until her death, was treated for dropsy. She
complained of incessant pain, which was only relieved when she rested on
her hands and knees. Of the three cases affecting the heart one has been
published (Mr Henderson’s), where the patient, a girl of nineteen years,
died suddenly whilst in the apparent enjoyment of perfect health. In
one of the other two cases (Mr May’s, of Tottenham), the left lung was
also involved. One case of hydatid disease affecting the spinal column
appears to have been originally an ordinary liver case. In Mr Cock’s
example of genuine mammary hydatids, the hooklets and echinococcus heads
were detected; but I am not sure that a similar result of microscopic
examination was obtained in the equally interesting example of hydatids
of the thyroid gland (also removed by Mr Cock). There are five bladder
cases, all apparently genuine (of which one has been published); and
there are also five other cases referred in the catalogue to the
kidneys, of which I regard two as doubtfully parasitic in character. Of
three cases of hydatid growths occupying the soft parts of the thigh,
two were under Mr Bryant’s care. The museum likewise contains an old
preparation of hydatids of the tibia, but its history has been lost.
There are also two brain cases, besides upwards of a score of more or
less characteristic and instructive cases of hydatids affecting the
liver.

Scattered amongst the museums connected with the larger provincial
schools and recognised hospitals there must be a great many valuable
preparations of hydatid disease; at all events, I judge so from the
inspection I have incidentally made of a few of the collections.

Of eleven preparations of human hydatids which I observed in the
Cambridge Anatomical Museum, apparently representing the same number
of cases, seven were connected with the liver and one with the lungs.
Those hydatids displayed in the “special series” of entozoa were of
uncertain seat. From the recently published and valuable ‘Notes’ by Dr
Bradbury, I have no doubt that considerable additions have been made to
the Cambridge Collection since my last visit.

The museum at Oxford contains some choice specimens of hydatids, but I
have only personally inspected a few of them. In the absence of original
notes, however, I am indebted to the kindness of Mr W. Hatchett Jackson
for supplying me with several interesting particulars. The anatomical
department of the Oxford Collection shows from one particular case two
hydatids that were found “under the dura mater.” In the pathological
department we find one hydatid from the liver of a male subject, and
also a preparation showing a number of small hydatids that were “coughed
up from the lungs of a female.” There are also in this department (Dr.
Acland’s) two examples of hydatids from the diaphragm, apparently
belonging to two separate cases. One is described as a large “hydatid
in the diaphragm covered by the pleura,” whilst the other is spoken of
as “springing from the diaphragm and projecting into the sac of the
pericardium.” There is likewise a preparation showing a number of small
specimens of hydatids that were passed _per anum_ by a female. It is
conjectured that they came from the liver.

The small pathological museum attached to the Brighton and Sussex
Hospital is particularly rich in hydatids. Amongst others, it contains
preparations illustrative of the remarkable case of hydatids in the
region of the prostate, communicated by Mr Lowdell, in the ‘Lancet,’ in
1846.

The comparatively large museum adjoining the Norfolk and Norwich
Hospital displays a choice series of hydatids, chiefly from the
collection of the late Mr Crosse. That eminent surgeon prepared a
special set of specimens to illustrate the process of natural cure
by calcareous degeneration; and I may here, perhaps, be pardoned for
mentioning that it was the study of these and other entozoa in Mr
Crosse’s Collection, some thirty or more years ago, that first drew
my attention to the phenomena of parasitic life. Illustrations of the
helminths in question are still in my possession. In one case (which is
instructive as indicating the possibility of death from the simplest
form and commonest habitat of an hydatid) a lad, twelve years old,
received a slight blow from a playmate. Something gave way, and death
speedily followed. It was found by post-mortem examination that a
solitary liver hydatid, rather larger than a cricket-ball, had been
ruptured. Although the case is almost unique, it is nevertheless by no
means pleasant to reflect upon the fact that under similar circumstances
a slight blow might prove fatal to any one, no matter in what internal
organ the bladder worm happened to be situated.

Before concluding my summary notice of the human hydatids contained in
the metropolitan and certain other museums, there is an interesting
literary contribution that I cannot pass unnoticed. In the November
number of the ‘Indian Medical Gazette’ for 1870 an article occurs in
which it is stated that the Calcutta Medical College Museum contains
eighteen specimens of hydatid cysts of liver. This fact was, it seems,
originally adduced to show, not the frequency, but rather the rarity,
of the occurrence of hydatids in India. However, from a valuable
communication by Dr James Cleghorn, which was published in the same
periodical for the following March, it appears that hydatids of the
liver are much more common in India than is generally supposed. This,
he says, is owing to the circumstance that many of the so-called cases
of tropical abscess are neither more nor less than examples of hydatid
cysts that have suppurated. Besides Cleghorn’s evidence, we have the
previous testimony of the Inspector General I. M. D., whose Report for
1868-69 I have already referred to in connection with _Cysticercus_
in beef. He says: “During some three months’ regular observation of
the animals killed at the Commissariat slaughter-house here, at least
70 per cent. of the beef livers may be calculated as thus affected.
Cobbold, writing of the _Tænia echinococcus_, says that ‘this little
tapeworm infests only the dog and the wolf.’ Therefore, considering the
immense number of pariah dogs fed on the refuse of animals infected with
hydatids, it seems more than probable that the parasite must attain its
strobila condition in their intestines, and through them be eventually
disseminated over the pastures on which the cattle graze.”

I now turn to a neglected phase of the subject from which much practical
instruction may be gathered. The consideration of the pathological
phenomena of hydatid disease as it affects the lower animals is of high
interest, and no prejudice should induce any medical man from accepting
such useful data as may be gathered from this source. The facts of
hydatid parasitism in animals, though often peculiar, are, for the most
part, of an order similar to those presented in the human subject. If
any medical practitioner thinks it beneath his dignity to study the
pathology of the lower animals, the conduct of John Hunter in this
respect is a standing protest against such narrowness.

The museum of the Royal College of Surgeons of England contains some of
the finest specimens of hydatids from the lower animals that are to be
seen anywhere, the very choicest of them having been selected by Hunter
himself. That distinguished man sought information from every available
source, and hydatids were for him of almost equal interest, whether
found in the body of a human being or in the carcase of an ox or an ass.
Now, at all events, neither pathologists nor sanitarians can well afford
to neglect comparative pathology; and, for myself, I am free to say that
the yearly exposition to the students of the Royal Veterinary College
of the phenomena of parasitic life amongst animals has brought with it
an ever-increasing knowledge of the most curious and often unlooked-for
information. Some of the data thus supplied are quite remarkable. Let
me also add that my studies of the entozoa of wild animals have put
me in possession of particulars of high value in regard to the larger
question of the origin of epidemics. Beasts, birds, reptiles and fishes,
of every description, are liable to succumb to internal parasites, and
there is practically no end to the variety of useful information to be
obtained from this source. I have collected materials almost sufficient
for a separate treatise on this department of the subject, but I fear I
shall never have either the time or opportunity to give the facts due
publicity. Here, for obvious reasons, I must for the most part restrict
myself to the hydatids properly so called.

Referring, in the first instance, to the hydatids of animals that have
the same mode of origin and exhibit the same general characteristics
as those found in man, I notice that four of the metropolitan museums
exhibit nine examples of liver Echinococci. The Hunterian Collection
shows specimens of this kind from the pig, monkey, zebra, and lion.
The museum at St Bartholomew’s Hospital contains two examples from the
pig and one from a cow; whilst the animal liver-hydatids preserved
in the King’s College and Guy’s Museums, respectively, are from the
pig and sheep. That from the latter is partly calcified. Respecting
animal hydatids affecting the lungs, the Cambridge Museum exhibits a
simple acephalocyst from a monkey, and the Guy’s Hospital Museum shows
a pulmonary hydatid from the kangaroo. In the museum at Oxford, Dr
Acland’s (pathological) department shows a preparation of “one large
echinococcus cyst from the abdomen of a baboon,” whilst Dr Rolleston’s
department (anatomical) displays the echinococcus itself from the
“cavity of the abdomen of the same animal.” The collection also contains
a variety of other bladder worms from different animals. The Hunterian
Museum, Lincoln’s Inn, exhibits four or five alleged examples of
hydatids from the kidney of the sheep, besides another from the spleen.
Some of these are of very doubtful character. A cystic kidney from the
sheep, preserved in the London Hospital Museum, and originally supposed
to have been due to hydatids, is (as hinted in the MS. catalogue)
certainly not of parasitic origin. In regard to the occurrence of
hydatids in the heart of animals the Hunterian series shows two good
examples from cattle, whilst the collection at University College
exhibits one taken from the wall of the left ventricle of a sow. This
was presented by Dr Elliotson.

In the museum of the Royal Veterinary College there are a number of
excellent preparations of true hydatids taken from various animals,
especially from cattle, swine, and sheep; and there are also many kinds
of bladder worms which, though often called “hydatid” by veterinarians,
have a totally different origin from that of the true Echinococci.
The so-called gid-hydatids (Cœnuri) and slender-necked hydatids
(_Cysticercus tenuicollis_) are of this description. Specimens of the
polycephalous brain hydatid, or Cœnurus, also exist in the museums
connected with St Bartholomew’s, Guy’s, and St Thomas’s Hospital
Medical Colleges, as well as in both the anatomical and pathological
departments of the Oxford Museum. Specimens of large Cœnuri occurring
in the soft parts of rabbits may be seen in the Guy’s Museum (presented
by Mr Carpenter). Similar characteristic specimens exist in the Oxford
Collection, labelled _C. cuniculi_, obtained from the “masseter and
infraspinatus” muscles of a rabbit. My private collection also contains
a recent addition of this remarkable hydatid, sent to me by Mr Alston
from Ayrshire. It is the only one I have seen from Scotland. In the
second half of this work these Cœnuri will again come under notice.
Three examples of the slender-necked hydatid (from a monkey and two
sheep respectively) may be seen in the Guy’s and University College
Collections, and there are several in the museum of the Royal Veterinary
College.

I cannot go out of my way to speak of other bladder worms, except so
far as to call attention to the heart of a bear preserved in the museum
at Guy’s, the walls of which are crowded with Cysticerci. That unique
preparation ought to be carefully examined and described. The Hunterian
Museum contains two magnificent specimens of hydatids affecting the
bones of cattle. In the one case a solitary vesicle occupies the shaft
of the humerus; whilst in the other several “acephalocysts” have taken
up their residence within the cancellous structure of the ilium.

In the matter of human mortality from hydatids I have already supplied
statistical evidence of the unenviable distinction which our Australian
colonies exhibit, and in addition to the facts brought forward I may add
that Dr Lewellin has mentioned to me a fatal case in which an hydatid
occupied the whole length of the vertebral canal. The patient was under
Dr Annand’s care. There could be no doubt as to the genuineness of the
case, as the spinal cyst was tapped during life, when echinococcus
hooklets were found.

Through Dr Lewellin I am also indebted to Dr H. B. Allen, pathologist at
the Melbourne Hospital, for the particulars of a case of hydatids of the
cerebrum, which are given as follows:

“J. Q--, aged 15, was admitted into the Melbourne Hospital on the 13th
November, 1877, suffering from partial left hemiplegia. He rapidly
became insensible and died next day. His mother furnished the following
history.

“He had been woodcarting in the bush for a considerable time, and while
thus engaged eight weeks before admission began to lose power in his
left arm and leg; gradually the paralysis increased, and he was taken
home, where he remained for six weeks. During this time he had every
week an attack of severe headache, and once he lost all sight for over
half an hour. Gradually the symptoms increased, and he was taken to the
hospital, but even then was able to walk with assistance part of the way.

“At the autopsy, when the calvarium was removed, a large cyst about
four inches in diameter was found on the mid-convexity of the right
hemisphere of the cerebrum, slightly towards its anterior part. It
formed a marked prominence on the anterior surface of the brain, and
was bounded superficially by the pia mater and arachnoid, which were
neither noticeably thickened nor adherent to the dura mater. On opening
the cyst it was seen to extend inwards and abut on the wall of the
lateral ventricle, and consisted of the ordinary gelatinous membrane,
studded internally with little granular eminences, some pellucid, some
opaque white. The contents were thin limpid fluid. The brain tissues
around presented scarcely any induration. All other organs structurally
healthy, congestion being the only morbid condition present.

“The specimen is preserved in the hospital museum, which contains two
other preparations of hydatids in the brain, and also an hydatid cyst of
large size growing from the interior of the frontal bone.”

In concluding this account of hydatids I may remark that, by the
employment of sanitary measures, the disorder might, in course of time,
be thoroughly stamped out. What these measures are I have already stated.

I need hardly say that the following bibliography by no means exhausts
the records of echinococcus disease. In Dr Albert Neisser’s recent
monograph nearly a thousand separate cases are quoted and classified.
The monograph of Dr Hearn, which is not mentioned in Neisser’s work,
also contains a valuable bibliography.

English literature. _Hydatids in general_ (BIBLIOGRAPHY No. 20 _a_).
--_Ballard, E._ (review of Henoch), ‘Med.-Chir. Rev.,’ 1854.--_Bird,
S. D._, ‘On Hydatids of the Lung; their diagnosis, prognosis, and
treatment,’ 2nd edit., Melbourne, 1877.--_Busk_, “On the Nat. Hist.
of the Echinococcus,” ‘Micr. Soc. Trans.,’ orig. series, vol. ii,
1849.--_Budd, G._, ‘Diseases of the Liver,’ Lond., 1845.--_Carmichael,
R._ (lecture), ‘Dub. Med. Press,’ 1840, p. 91.--_Cobbold, T. S._,
‘Entozoa,’ chap. vii and viii, 1864.--_Idem_, “On Hydatid Disease”
(lecture), ‘Lancet,’ June, 1875, p. 850.--_Idem_, “On Hydatid Diseases
of Man and Animals” (museum specimens), in a series of articles
contributed to ‘Brit. Med. Journ.,’ Oct., 1875, to Jan., 1876; fully
reprinted in the ‘Veterinarian,’ Feb., 1876.--_Copland, J._ (Art.
“Hydatids”) in his ‘Dictionary,’ 1848.--_Davies, T._, ‘Lond. Med. Gaz.,’
1835.--_Gairdner, J._, and _Lee_, ‘Edinb. Med. and Surg. Journ.,’
1844.--_Goodsir, H. S. D._ (same ref., Lee’s case), 1844.--_Goodsir, J._
(same ref.), 1844.--_Gross, S. D._, ‘Elements of Path. Anat.,’ chap.
xv, Boston, U.S., 1839.--_Hawkins, C._, ‘Lancet,’ 1833.--_Hjaltelin_,
‘Edinb. Med. Journ.,’ 1867; see also Dobell’s ‘Report on the Progress
of Practical and Scientific Medicine,’ London, 1870.--_Hodgkin, T._,
in his ‘Lectures on the Serous and Mucous Membrane,’ 1838.--_Kerr,
W._ (art. “Hydatids”) ‘Cyclop. of Pract. Med.,’ 1833.--_Leared, A._
(prevention), ‘Med. Times and Gaz.,’ 1863.--_MacGillivray, P. H._ (see
below, miscell. cases).--_Murchison C._, in his ‘Clinical Lectures,’
Lond., 1868, p. 54; 2nd edit., 1877.--_Idem_, “Hydatid Tumours of the
Liver; their danger, their diagnosis, and their treatment,” ‘Edinb.
Med. Journ.,’ 1865.--_Nettleship, E._, “Notes on the Rearing of _Tænia
echinococcus_ in the Dog from Hydatids, &c.,” ‘Proc. Royal Soc.,’ 1866,
p. 224.--_Rose, C. B._, “On the Vesicular Entozoa, and particularly
Hydatids,” ‘Lond. Med. Gaz.,’ 1833-4, p. 204.--_Stephens_, ‘Lancet,’
1833; the ‘Veterinarian,’ 1831, p. 284.--_Thompson, T._ (remarks),
‘Lancet,’ 1851.--_Wilson, E._, “On the Structure, Classification,
and Development of the _Echinococcus hominis_,” ‘Med.-Chir. Trans.,’
1845.--_Yates, G._, “On Hydatid Disease,” ‘Assoc. Med. Journ.,’ vol.
iii, 1855.

_Hydatids of the liver_ (BIBLIOGRAPHY No. 20 _b_).--_Abercrombie,
T._, ‘Lond. Med. Journ.,’ vol. ii, p. 276, 1829.--_Alison, S. S._,
‘Lond. Med. Gaz.,’ 1844.--_Barclay_, ‘Brit. Med. Journ.,’ Nov.,
1868, p. 494.--_Barker, T. A._ ‘Lancet,’ and ‘Path. Soc. Trans.’
1855.--_Barlow_, ‘Lond. Med. Gaz.,’ 1857.--_Beith_, ‘Path. Soc. Trans.,’
1852.--_Bradbury, J. B._ (six cases), ‘Brit. Med. Journ.,’ Oct.,
1874, pp. 526-558.--_Idem_, ‘Brit. Med. Journ.,’ 1876, vol. ii, p.
646.--_Brinton_, ‘Lancet,’ 1854.--_Idem_, ‘Lancet,’ 1858.--_Bristowe,
T. S._, ‘Path. Soc. Trans.,’ 1851.--_Idem_, ‘Path. Soc. Trans.,’
1858.--_Broadbent, W. H._, “Hydatids of the Liver; Paracentesis followed
by free Incision;” ‘British Med. Journ.,’ Nov. 30th, 1878.--_Brodie, B.
C._ (supposed), ‘Lond. Med. Gaz.,’ 1828.--_Brook, C._, ‘Lancet.,’ Feb.,
1868, p. 162.--_Buchanan_, ‘Surg. Med. Gaz.,’ 1861.--_Budd, W._, ‘Brit.
Med. Journ.,’ 1859.--_Chambers, T. K._, ‘Lond. Med. Gaz.,’ 1846.--_Cox,
T._, ‘Lancet,’ and ‘Med.-Chir. Trans.,’ 1838.--_Crosse, J. G._,
‘Lancet,’ 1837.--_Curling T. B._, ‘Med.-Chir. Trans.,’ 1840.--_Daly,
O._ (supposed), ‘Brit. Med. Journ.,’ 1859.--_Davies H._, ‘Path. Soc.
Trans.,’ 1848.--_Dickenson_, ‘Lond. Med. Gaz.,’ 1861; ‘Path. Soc.
Trans.,’ 1862.--_Duncan, A._ (near the portal vein), ‘Edin. Med. and
Surg. Journ.,’ 1808.--_Duncan, P. M._ (several cases), ‘Prov. Med. and
Surg. Journ.,’ 1850-52.--_Elliotson, J._, ‘Lancet,’ 1832.--_Fearn, S.
W._ (immense cyst), ‘Brit. Med. Journ.,’ Nov., 1868, p. 496.--_Fletcher,
T. B. E._, ‘Prov. Med. and Surg. Journ.,’ 1846.--_Freer, W. G._,
‘Lancet,’ and ‘Prov. Med. and Surg. Journ.,’ 1845.--_Gaitskell, W._
(1000 discharged) ‘Lond. Med. Repository,’ 1815.--_Gulland_, ‘Edin. Med.
Journ.,’ 1860.--_Harley, J._, ‘Lancet,’ May, 1866, p. 538, and ‘Med.
Chir. Trans.,’ 1866.--_Idem_, in ‘St Thomas’s Hospital Reports,’ 1877,
p. 291.--_Hastings, C._, ‘Brit. Med. Journ.,’ 1858.--_Heaton_, ‘Brit.
Med. Journ.,’ Oct. 31st, 1874, p. 557.--_Heckford, N._, ‘Brit. Med.
Journ.,’ Sept., 1868, p. 332.--_Hillier_, ‘Lancet,’ and ‘Path. Soc.
Trans.,’ 1855.--_Hutchinson, J._, ‘Lancet,’ Oct., 1862.--_Inglis, A._,
‘Brit. Med. Journ.,’ 1859.--_Leared A._ (Hjaltelm’s case), ‘Path. Soc.
Trans.,’ 1863.--_Logan_ (thousands present), ‘Path. Soc. Trans.,’ and
‘Med. Times and Gaz.,’ March, 1865, p. 243.--_Lyon, E._ (several cases),
‘Prov. Med. and Surg. Journ.,’ 1850.--_Murchison, C._ (rupture through
pleura), ‘Path. Soc. Trans.,’ 1861.--_Idem_, ‘Lancet,’ July, p. 75,
1868.--_Page_, ‘Brit. Med. Journ.,’ and ‘Lancet,’ Nov., 1864.--_Pavy,
F. W._ (expectorated), ‘Med. Gaz.,’ 1851.--_Idem_, ‘Med.-Chir.
Trans.,’ and ‘Lancet,’ Sept., 1866, p. 234.--_Peacock_ (two cases,
expectorated), ‘Lond. Med. Gaz.,’ and ‘Lancet,’ 1850.--_Pemberton, O.
A._ (rupturing diaphragm), ‘Prov. Med. Journ.,’ 1848.--_Philipson_,
‘Brit. Med. Journ.,’ Oct. 31st, 1874, p. 557.--_Pollock, J._ (fatal),
‘Path. Soc. Trans.,’ 1854.--_Idem_ (opening into lung), ‘Lancet,’
Jan., 1865, p. 63.--_Rees, G. O._, ‘Guy’s Hosp. Rep.,’ 1848.--_Idem_
(lecture), ‘Lond. Med. Gaz.,’ 1849.--_Richards, C. C._, ‘Lancet,’
Jan., 1865, p. 261.--_Roberts_, ‘Lancet,’ 1833.--_Russell, J._, ‘Prov.
Med. and Surg. Journ.,’ 1851.--_Sadler, M. T._ (Cæsarean section),
‘Med. Times and Gaz.,’ Aug., 1864, p. 141.--_Salter; H._, ‘Path.
Soc. Trans.,’ 1860.--_Savory, W. S._ (letter), ‘Lancet,’ May, 1866,
p. 410.--_Sherwin, H. C._ (fatal), ‘Edin. Med. and Surg. Journ.,’
1823.--_Sibson, F._, ‘Lancet,’ July, 1868, p. 76.--_Sloane, J._
(puncture), ‘Brit. Med. Journ.,’ 1858.--_Thompson H._, ‘Path. Soc.
Trans.,’ and ‘Lancet,’ 1858.--_Trimnell, G. C._, ‘Lond. Med. Repos.,’
1821.--_Ward, S. H._, ‘Lancet,’ 1868, vol. ii, pp. 141, 305, and
474.--_Wearne, V._ (perforating diaphragm), ‘Brit. Med. Journ.,’ July,
1864, p. 31.--_Wilks_ (escaping by gall-ducts), ‘Path. Soc. Trans.,’
1860.--_Young, J._, ‘Edin. Med. and Surg. Journ.,’ 1829.

_Hydatids of the liver and other organs together_ (BIBLIOGRAPHY No. 20
_c_).--_Beale, L._ (kidney), ‘Arch. of Med.,’ vol. i, p. 31, 1857; see
also same case by _Bristowe_, ‘Path. Soc. Trans.,’ 1853.--_Billing_
(lungs), ‘Lond. M. and S. Journ.,’ 1831, p. 58.--_Griffith, J. W._
(abdomen), ‘Lond. Med. Gaz.,’ 1844.--_Heslop, T. P._ (kidney), ‘Month.
Journ. of Med. Sci.,’ 1850.--_Richardson_ (kidney, Dr Mackinder’s case),
‘Lancet,’ 1855.

_Liver cases occurring in America_ (BIBLIOGRAPHY No. 20 _d_).
--_Alexander, E._ (200 present), ‘Boston Med. and Surg. Journ.,’
1838.--_Finnell_, ‘New York Med. Journ.,’ 1856, p. 216.--_Minot, T._
(expectorated), Bost. Soc. for Med. Improv., 1859, and ‘Brit. Med. and
Surg. Journ.,’ 1860, p. 297.--_Webber, J. E._, ‘New York Med. Times,’
1853, and ‘Bost. Med. and Surg. Journ.,’ 1853, p. 126.

_Hydatids of the lungs and pleura_ (BIBLIOGRAPHY No. 20 _e_).
--Cholmeley, ‘Guy’s Hosp. Rep.,’ 1837.--_Dowling, F._, ‘Australian Med.
Journ.,’ 1864.--_Duffin, A. B._, ‘Beale’s Archives,’ 1857, vol. i,
p. 253.--_Hare,_ ‘Path. Soc. Trans.,’ 1857-8.--_Hill, J._, ‘Med. and
Philos. Comm.,’ 1784, vol. ii, p. 303.--_Hutchinson, J._, ‘Path. Soc.
Trans.,’ 1854.--_Kirkes, W. S._, ‘Med. Times and Gaz.,’ 1851.--_Leared,
A._, ‘Path. Soc. Trans.,’ 1857.--_Peacock_, ‘Lancet,’ 1850.--_Ridge,
J._, ‘Guy’s Hosp. Rep.,’ 1836, p. 507.--_Rigden, G._, ‘Prov. Med. and
Surg. Journ.,’ 1852.--_Smith, F. G._, ‘North Amer. Med.-Chir. Rev.,’
1858, p. 333.--_Todd, R. B._, ‘Med. Times and Gaz.,’ 1852.

_Hydatids of the Kidney_ (BIBLIOGRAPHY No. 20 _f_).--_Adams, A. L._,
‘Lancet,’ 1864, p. 375.--_Barker, T. H._, ‘Glasg. Med. Journ.,’ 1855-6,
p. 439.--_Duncan_, ‘Liverpool Med. Journ.,’ 1834.--_Dunn, J._, ‘Lond.
Med. Repos.,’ 1817.--_Fussell, E. F._, ‘Lancet,’ 1851.--_Lettsom_ (two
cases), ‘Trans. Med. Soc. of Lond.,’ 1789, p. 33.--_Ward, W._, ‘Lancet,’
1846.--_Wilson, J._ (lecture) ‘Lond. Med. Repos.,’ 1822.

_Hydatids of the spleen, omentum, and abdominal cavity_ (BIBLIOGRAPHY
No. 20 _g_).--(Anonymous), ‘Edin. Med. and Surg. Journ.,’ 1819, p.
50.--_Bailey, F._, ‘Lond. Med. Repos.,’ 1826.--_Bright, R._ (remarks
on cases) ‘Guy’s Hosp. Rep.,’ 1838.--_Bryant, T._ (simulating ovarian
disease), ‘Guy’s Hosp. Rep.,’ 1868, p. 235.--_Budd, G._ (omentum),
‘Med. Times,’ 1838.--_Idem_ (rep. by Parsons), ‘Brit. Med. Journ.,’
1859.--_Burman_, ‘Prov. Med. Journ.,’ 1847.--_Crowther, C._, ‘Edin.
Med. and Surg. Journ.,’ 1826, p. 49.--_Greenhow, E. H._, ‘Lancet,’
1862.--_Little, W. I._ (simulating ovarian disease), ‘Brit. Med.
Journ.,’ 1857.--_Macleay, K._, ‘Edin. Med. and Surg. Journ.,’
1806.--_Morley, J._ (partly pelvic), ‘Lancet,’ 1845.--_Newman, W._
(simulating ovarian disease), ‘Obstetr. Soc. Trans.,’ vol. iv,
1862.--_Obre_ (peritoneal), ‘Path. Soc. Trans.,’ 1854.--_Ogle, J._
(omentum), ‘Path. Soc. Trans.,’ 1860.--_Simpson, A. R._ (peritoneal),
‘Edin. Med. Journ.,’ 1861-62.--_Simpson, J. Y._, ‘Assoc. Med. Journ.,’
1854, p. 137.--_Thompson, T._, ‘Lancet,’ 1843.--_Thompson, A. T._
(simulating ovarian disease), ‘Lancet,’ 1833.

_Hydatids within the pelvic cavity_ (BIBLIOGRAPHY No. 20 _h_).
--_Birkett, J._ (voided), ‘Guy’s Hosp. Rep.,’ 1851, p. 300.--_Bryant,
T._, ‘Lancet,’ 1865, pp. 566 and 589.--_Corrigan_ (ovarian), ‘Dub.
Quart. Journ.,’ vol. i, 1846.--_Crampton_ (ovarian), ‘Dub. Quart.
Journ.,’ vol. ii, 1846.--_Curling, T. B._ (bladder), ‘Med. Times
and Gaz.,’ 1863.--_Farre, A._, ‘Lancet,’ 1862.--_Habershon_, ‘Path.
Soc. Trans.,’ 1860.--_Hughes_, ‘Lond. Med. Gaz.,’ 1861.--_Hunter,
T._, ‘Trans. of Soc. for Improv. of Med. and Chir. Knowledge,’ 1793,
p. 34.--_Jennings_ (simulating pregnancy), ‘Dublin Quart. Journ.,’
1855.--_Lowdell_, ‘Lancet,’ 1846.--_Maunder_, ‘Lancet,’ Sept., 1864, p.
351.--_Sadler, M. T._ (voided), ‘Med. Times and Gaz.’ 1865.--_Simon, J._
(voided), ‘Lancet,’ 1853.--_Wakley_, ‘Lancet,’ 1863.--_White_, ‘Med.
Gaz.,’ 1842.

_Hydatids of the heart and blood-vessels_ (BIBLIOGRAPHY No. 20 _i_).
--_Bigger_, ‘Dub. Path. Soc.’ Rep. in ‘Lancet,’ 1830.--_Budd, G._,
‘Path. Soc. Trans.,’ 1839.--_Coote, H._, ‘Lond. Med. Gaz.,’ 1854.
--_Goodhart_, ‘Brit. Med. Journ.,’ Nov. 27, 1875.--_Price, D._, ‘Lond.
Med. Repos.,’ 1822.--_Smith, R._, ‘Lancet,’ 1838.--_Trotter_, ‘Chem. and
Med. Essays,’ 1736.--_Wilks_ (Henderson’s case), ‘Path. Soc. Trans.,’
1860.

_Hydatids of the brain and cranial cavity_ (BIBLIOGRAPHY, No. 20 _k_).
--(Anonymous) ‘Lancet,’ April, 1864, p. 444.--_Bailey, F._, ‘Lancet,’
1825; ‘Lond. Med. Repos.,’ 1826.--_Barker, T. A._, ‘Path. Soc.
Trans.,’ 1858.--_Bennett, J. R._, ‘Med. Times and Gaz.,’ Jan.,
1862.--_Berncastle, J._, ‘Lancet,’ 1846.--_Bree, C. R._, ‘Lancet,’
1837.--_Brittan, F._, ‘Brit. Med. Journ.,’ 1859.--_Burton_, ‘Med.
Times and Gaz.,’ 1862.--_Dagleish, G._, ‘Lancet,’ 1832.--_Fletcher, T.
B. E._, ‘Assoc. Med. Journ.,’ vol. iii, p. 161, 1855.--_Headington_,
‘Edin. Med. and Surg. Journ.,’ vol. xv, 1819, p. 504.--_Helsham_, ‘Med.
Comment.,’ vol. xiii, 1788, p. 289.--_Macnamara, W. H._, ‘Brit. Med.
Journ.,’ vol. ii, p. 616, 1876.--_Rigden, G._, ‘Prov. Med. and Surg.
Journ.,’ 1852.--_Stewart, J._, ‘Lancet,’ 1848.--_Sturton_, ‘Lancet,’
1840.--_Wilson, E._, ‘Lancet,’ 1848.

_Hydatids of the bones_ (BIBLIOGRAPHY No. 20 _l_).--_Cobbold, T. S._,
“Notice of Specimens of Tibial Hydatids in Nottingham,” ‘Brit. Med.
Journ.,’ 1865, and in the ‘Veterinarian,’ Feb., 1866.--_Idem_, “Notice
of Specimens from the Tibia in the Mid. Hosp. Museum,” _ibid.--Cooper,
A._, “Foster and Lucas’s case affecting the Tibia,” ‘Surg. Essays,’
Lond., 1818.--_Coulson, W._ (tibia), ‘Med.-Chir. Trans.,’ 1858; see
also _Daubeny, H._, ‘Path. Soc. Trans.,’ 1858.--_Erichsen, J. E._, in
his ‘Surgery,’ 4th edit., pp. 728, 823, and 948, Lond., 1864.--_Hunter,
W._ (tibial, Mus. Spec. at Glasgow), quoted in ‘L’Expérience,’ 1838, p.
531.--_Keate, R._ (os frontis), ‘Med.-Chir. Trans.,’ 1819.--_Lambert,
J._ (tibia), ‘Lancet,’ 1826.--_Thompson, H._ (Hearne’s tibial case),
‘Path. Soc. Trans.,’ 1859.--_Webster, F. W._ (tibia), ‘New Eng. Med.
Journ. of Med. and Surg.,’ 1819.--_Wickham, W. J._ (tibia), ‘Lond. Med.
and Phys. Journ.,’ 1827.

_Hydatids of the breast, muscles, and soft parts_ (BIBLIOGRAPHY No. 20
_m_).--_Adams, J._ (abdominal parietes), ‘Lancet,’ 1851.--(Anonymous),
“Hyd. in the Eye of a Girl,” ‘Boston Med. and Surg. Journ.,’ 1849,
p. 28.--_Baird, J._ (muscles), ‘Edin. Med. and Surg. Journ.,’
1821.--_Birkett, J._ (mammary), ‘Lancet,’ March, 1867, p. 263.--_Brodie,
B. C._ (near scapula), ‘Lancet,’ 1818.--_Bryant, T._ (thigh), ‘Path.
Soc. Trans.,’ 1859.--_Idem_ (thigh), ‘Lancet,’ 1862.--_Idem_ (breast),
‘Path. Soc. Trans.,’ and ‘Lancet,’ Nov., 1865, p. 565.--_Cholmeley_
(from right side), ‘Lancet,’ 1826.--_Cooper, B. B._ (neck and breast,
two cases), ‘Guy’s Hosp. Rep.’ 1851.--_Idem_, in Birkett’s work on the
‘Breast,’ p. 183; the ‘Institute,’ vol. i. p. 119, 1850.--_Dixon, J._
(neck), ‘Lancet,’ 1851.--_Henry, M._ (breast), ‘Lancet,’ Nov., 1861,
p. 497.--_Hewndon, A._ (neck), by Tyson, in ‘Phil. Trans.,’ 1706-7,
vol. xxv, p. 2344.--_Jones, S._ (subperitoneal), ‘Path. Soc. Trans.,’
1854.--_Rankine, J._, “Supposed Hyd. in Synovial Sheaths,” ‘Edin. M. and
S. Journ.,’ 1830.--_Sands_ (neck), ‘Amer. Med. Times,’ 1861, vol. ii, p.
376.--_White_ (breast and arm), ‘Lancet,’ 1839.

_Hydatids of uncertain seat, or miscellaneous cases and observations_
(BIBLIOGRAPHY No. 20 _n_).--_Barrett_, ‘Lond. Med. Gaz.,’
1838.--_Durrant, C. M._ (Ipswich Hosp.), ‘Prov. Med. and Surg.
Journ.,’ 1851.--_Fagge, H._, ‘Lancet,’ July, 1868, p. 76.--_Greenhow,
J. M._ (intestinal), ‘Lancet,’ 1823.--_Howship, J._ (case, with
speculative remarks), ‘Edin. M. and S. Journ.,’ 1835.--_MacGillivray,
P. H._ (orbit, &c.), ‘Austral. Med. Journ.,’ Aug., 1865.--_Idem,
ibid._, March, 1867.--_Idem_ (3rd series of cases), _ibid._, July,
1872.--_Idem_ (treatment with kamala), _ibid._, July, 1872.--_Markham,
W. O._, “On the ‘son hydatique,’” ‘Assoc. Med. Journ.,’ 1856, p.
1072.--_Musgrave_ (letter to Sir H. Sloane), ‘Phil. Trans.,’ vol. xxiv,
1704-5.--_Phillips_, ‘Lancet,’ July, 1868, p. 77.--_Russell, J. J._,
‘Dub. Journ.,’ 1838.--_Salter, H._, ‘Path. Soc. Trans.,’ 1854.--_Ward,
T. O._, ‘Lond. Med. Gaz.,’ 1837.

_Hydatids of animals (acephalocysts)_ (BIBLIOGRAPHY No. 20 _o_).
--_Böllinger_ (see Bibl. No. 49).--_Cobbold_, ‘Manual,’ l. c. (Bibl. No.
2), 1874.--_Crisp, E._ (in a turkey and in hogs), ‘Path. Soc. Trans.,’
1863.--_East, J._ (see Steel).--_Findeisen_, “Echin. in der Lunge,”
‘Repertorium für Thierheilkund.,’ 1875, s. 48.--_Gross, S. D._ (in
swine), ‘Elements of Path. Anat.,’ 1845, p. 118.--_Hunter, J._, “A Cyst
(hydatid) which was filled with water, formed in and filling up the Bone
(humerus) of an Ox (from Hunterian MS.),” more fully described in the
‘Catalogue of the Mus. Lond. Coll. Surg.,’ “Path.,” vol. ii, prep. No.
864, p. 201, 1847.--_Idem_, “On Hydatids in Sheep” (supp. to Trans. of a
Soc., l. c., _supra_), 1793.--_Hutchinson, J._, “Hydatid in the Eye of a
Horse,” ‘Path. Soc. Trans.,’ and ‘Lancet,’ 1857.--_Huxley, T. H._, “On
the Anatomy and Development of _Echinoc. veterinorum_ (from a Zebra),”
‘Proc. Zool. Soc.,’ 1852.--_Kirkman, J._, “Chronic Disease of the Bones
of the Cranium of a Horse, associated with the existence of Hydatids
within a Cyst at the inferior part of the Orbit,” the ‘Veterinarian,’
vol. xxxvi, p. 77, 1863.--_Lepper_, “Hydatids in the Kidney of a Lamb,”
the ‘Veterinarian,’ 1863, p. 524.--_Martin, J._ (in the liver of a sow),
‘Vet. Assoc. Trans.,’ 1842-3, pp. 330 and 364.--_Moorcroft, W._ (in the
brain of a cow), ‘Med. Facts and Observ.,’ vol. iii, 1792.--_Morgan, A._
(in the brain of a mare), the ‘Veterinarian,’ 1855, p. 396.--_Peech,
S._ (in the muscles of a horse), the ‘Veterinarian,’ 1854, pp. 80
and 209.--_Siedamagrotzky_ (see Bibliog. No. 49).--_Simonds, J. B._,
“Remarks on Mr. Scruby’s case of Hydatids in the Liver of a Sheep,”
‘Trans. of Vet. Assoc.,’ 1842-3, p. 331.--_Steel, J. H._ (in liver of
a cow; Mr East’s case), the ‘Veterinarian,’ 1878, p. 441.--_Stoddart_
(in liver of a cow), the ‘Veterinarian,’ 1838, p. 637.--_Thudichum,
J. L. W._ (in sheep), ‘Assoc. Med. Journ.,’ 1856, p. 195.--_Vincent,
J. P._ (in horse, causing lameness), the ‘Veterinarian,’ 1848, p.
674.--_Walker, A._ (in the liver of a sow), ‘Vet. Record,’ 1846, p.
185.--_Woodger_ (in the brain of a horse), the ‘Veterinarian,’ 1863, p.
75.

_Foreign Literature. Human Hydatids_ (BIBLIOGRAPHY No. 20 _p_).
--_Böcker_, ‘Zur statistik der Echinoc.,’ Berlin, 1868.--_Davaine, C._,
‘Traité’ (l. c., Bibl. No. 1), p. 350, 1860; 2nd edit. p. 369,
1877.--_Idem_, “Recherches sur les hydatides, les échinoc., &c.,”
‘Gaz. Méd. de Paris,’ 1855.--_Idem_, “Recherch. sur le frémissement
hydatique,” ‘Gaz. Med.,’ 1862.--_Eschricht_, ‘Danske videnskab. selsk.
forhandl.,’ 1853.--_Finsen_, ‘Ugeskrift for Läger,’ Bd. iii, 1867; see
also ‘Brit. and For. Med.-Chir. Rev.,’ 1868, p. 324; also ‘Schmidt’s
Jahrb. für Med.,’ 1867, s. 181.--_Guérault_, “Sur la maladie hydatique,
&c.,” ‘Gaz. des Hôp.,’ 1857.--_Hearn, A. W._, ‘Kystes hydatiques du
poumon et de la plèvre,’ Paris, 1875.--_Heller, A._, “Die Schmarotzer
der Leber,” von Ziemssen’s ‘Handbuch d. Spec. Pathol. und Therapie,’
Bd. viii, s. 559.--_Krabbe, H._, “Maladie causée en Island par les
Échinocoques,” in his ‘Recherches Helminthologiques,’ p. 41, Paris,
1866; ‘Helm. Undersøgelser,’ Copenhagen, 1865, p. 40.--_Idem_, “Die
echinoc. der Islander,” ‘Archiv für Naturg.,’ 1865, and in ‘Den
med. Skole i Reykjavik,’ 1868.--_Idem_ (see T. R. Jones, Bibl. No.
2).--_Leuckart, R._ (l. c., Bibl. No. 1), Bd. i, s. 335, 1863; Bd.
ii, s. 859, 1876.--_Linder_, ‘Echinococcen der Leber,’ Leipsic,
1869.--_Naunyn_, ‘Archiv für Anat., Physiol.,’ &c., 1862-3.--_Neisser,
A._, ‘Die echinococcen Krankheit.,’ Berlin, 1877.--_Rassmussen_,
‘Bidrag til Kundskab om Echinoc.,’ &c., 1865; see also ‘Brit. and For.
Med.-Chir. Rev.,’ 1866, p. 285, and 1867, p. 424.--_Schmalfuss_, ‘Ueber
Leberechinococcus,’ Breslau, 1868.--_Tommasi, T._, ‘Storia di un caso di
Echinoc.,’ &c., in an appendix (Nota) to his edition of my ‘Lectures’
(Vermi, &c.), Milan, 1873, p. 153.

NOTE.--As Leuckart, Davaine, and especially Neisser offer exhaustive
analyses of the French and German literature of human hydatids, I will
only give the authors’ names attached to such additional foreign memoirs
and cases as have been published in England. These are quoted in my
‘Introductory Treatise on the Entozoa.’ Full references will be found in
the “Bibliography” of that work under the following heads:--_Andral_
(pulmonary veins), _Angeli_, _Auglagnier_ (bladder), _Baillarger_
(brain), _Boinet_ (liver), _Chaubasse_ (abdominal), _Cruveilhier_
(liver and spleen), _Dupuy_ (hydatids in animals), _Demarquay_ (liver),
_Dupuytren_ (muscles and viscera, &c.), _Fouquier_ (lungs), _Gayet_
(liver), _Goyrand_ (liver), _Guérard_, _Guillot_, _Hedinger_ (brain),
_Heintz_ (liver), _Held_ (thigh), _Heller_ (lip), _Klencke_ (blood,
&c.), _Kuhn_, _Lafforgue_ (liver), _Legroux_, _Livois_, _Luschka_
(liver), _Martinet_ (brain, liver), _Maug_ (hand), _Meissner_, _Micheá_
(brain), _Moissenet_ (liver), _Montault_ (brain), _Morrisseau_,
_Nicolai_ (liver), _Oerstelen_ (kidney), _Pohl_ (abdominal),
_Quinquirez_ (bladder), _Récamier_ (abdominal), Richard (liver), Roget
(lungs), Roux (pelvic), _Rüttel_ (brain), _Schleissner_, _Sichel_,
_Sömmering_ (eye), _Skoda_, _Tomowitz_ (bladder), _Zeder_ (brain).

Additional references to the echinococcus disease as it occurs in
animals will be found at the close of the section devoted to the
parasites of Ruminants (Bibliography No. 49), and I shall recur to the
subject of mortality from “worms” further on.



SECTION III.--NEMATODA (Round Worms).


_Trichina spiralis_, Owen.--The progressive triumphs of biological
science are well epitomised in the history of the discovery, and in
the record of the gradual manner in which we have obtained our present
complete knowledge of the structure and development of this small
entozoon.

Although the facts connected with the original discovery are clear and
indisputable, much error still pervades foreign literature on this
head. Without a doubt Mr Hilton was the first to suggest the parasitic
nature of the capsules first spoken of as “gritty particles.” With Sir
James Paget, however, rests the true discovery and determination of the
nematoid character of the worm itself. With Professor Owen remains the
honor of having first scientifically verified, described, and named
the entozoon. Some have sought, without good reason, to alter Owen’s
nomenclature; yet not only the generic title, but nearly all else that
he wrote concerning the parasite, must be allowed to stand.

In relation to the capsules, it is true that prior claims of discovery
have been put forward; but whilst Peacock’s preparation of the “little
bodies” testifies to the fact of his having seen the capsules before
other English observers, including Wormald, it was Hilton who first
surmised their parasitic character. As for the claims of Klencke and
Tiedemann, they are practically of no value, even if it be admitted that
the former may have at an early period seen something resembling this
nematode, and that the “stony concretions” encountered by the latter
were degenerated capsules.

On no subject have I desired to write with more accuracy and precision
than on this, and lest the above remarks should appear to be somewhat
partial, I now purposely re-state the facts as they have presented
themselves to me during a full and prolonged study of the entire
literature of the subject. If it be asked with whom rests the discovery
of _Trichina_, the reply must be framed with a due regard to precise
issue at stake. The first recognition of the capsules as parasitic
products is fairly claimed by Hilton; the worm by Paget; the zoological
allocation and nomenclature by Owen; the adult worm by Virchow; the
developmental phenomena by Leuckart; the rearing of the larvæ by Herbst;
and to crown all, the clinical importance of the parasite by Zenker. Due
regard being had to these relative claims, I think the following more
extended statement will be found to be true and just in all its bearings.

In the year 1834 Sir James Paget, then a student, first actually
determined the existence of the nematode entozoon, which was
subsequently more completely described by Professor Owen. The discoverer
was assisted by the celebrated botanist, Robert Brown, who lent his
microscope for the purposes of examination. In the following year
Professor Owen first scientifically described and named the flesh-worm
(_Trichina spiralis_) in the published transactions of a learned
society. He first fully interpreted the true zoological position of the
parasite. Sir J. Paget’s colleague, Mr. Wormald, had “more than once”
previously noticed the characteristic specks “in subjects dissected at
St Bartholomew’s Hospital.” He transmitted the individual specimens
which enabled Owen to draw up his valuable paper. It is clear, however,
that Mr Hilton was the first to suggest the parasitic and animal nature
of the specks observed in human muscle. As the “find” was made in 1832,
he anticipated Wormald in his observation of the “gritty” particles in
dissecting-room subjects, describing the bodies as “probably depending
upon the formation of very small Cysticerci.” Nevertheless, according
to Dr Hodgkin, “the first observation of these little bodies was
made in 1828” by Mr H. Peacock. The latter made a dry preparation of
the _sterno-hyoideus_ muscle to display the specks. That preparation
is the oldest in existence, and may be seen in Guy’s Museum. It may
further be remarked that Henle, Küchenmeister, Davaine, myself, and
others, have pointed to a notice by Tiedemann as probably, or possibly,
indicating a prior observation of the specks. Leuckart rejects the
evidence. Dr Pagenstecher appears to be in doubt as to the nature of
the bodies in question. As the passage in question possibly gave a
rough and imperfect description of the now familiarly known calcified
Trichina capsules, I give a translation of it (Froriep’s ‘Notizen,’
1822, Bd. i, s. 64):--“At a post-mortem examination of a man who had
been a great brandy-drinker, and who died from thoracic dropsy after
several severe attacks of gout, Tiedemann found white stony concretions
in most of the muscles, especially at the extremities. They lay in the
cellular tissue between the fibre-bundles, frequently also attached to
(or near) the walls of the arteries, being from two to four lines long,
and roundish. The chemical examination conducted by Gmelin yielded
seventy-three parts phosphate of lime, seven parts carbonate of lime and
twenty parts animal matter, resembling albumen or fibrin.” In regard
to this notice Dr Pagenstecher (‘Die Trichinen,’ s. 4) has remarked
that Tiedemann’s “communication was also referred by Henle to such a
parasitic development when he subsequently found Trichina; and in this
sense it was afterwards received by Diesing, Küchenmeister, and Davaine.
But it has been rejected by Leuckart on account of the size (from two
to four lines) and seat of the concretions. True, it has never yet been
observed that the capsuled Trichina (not measuring a tenth part of that
diameter) subsequently constituted centres of gouty deposit exceeding
their own bulk, nor is it likely that they should. Seeing, however,
as we often do, that errors respecting size have crept into works on
Trichina, we shall not need to lay much stress upon these statements;
still less so since the notice is very superficial, and its character is
essentially of a physiologico-chemical nature. But this, at least, seems
to us decisive, that when Bischoff, at Heidelberg, wrote on a case which
occurred in Heidelberg, not one single word was mentioned respecting
a former case, if such should have happened, although Tiedemann and
himself were on terms of close intimacy.” So much for Tiedemann. In
regard to Klencke’s claims, the same observer writes:--“Klencke has
asserted that he had already drawn Trichinæ in the year 1829, and that
he had seen them again in 1831. This subsequent statement has no kind of
confirmation. The unreliableness, mistakes, and self-deceptions in the
helminthological writings of Klencke have been repeatedly exposed some
twenty years ago.” Prior to this criticism by Pagenstecher, Professor
von Siebold and several other well-known helminthologists had already
commented on Klencke’s assertions in the same destructive manner.

In regard to the experimentation and the valuable instruction
thus acquired, it appears that Herbst was the first to rear
muscle-flesh-worms, or encapsuled Trichinæ, in animals (1850); whilst
Virchow was probably the first to rear and recognise sexually-mature
intestinal Trichinæ in a dog (‘Deutsche Klinik,’ 1859, s. 430); yet,
without doing injustice to others, it must be added that it remained
for Prof. Leuckart to offer a full, complete, and correct solution of
the principal questions relating to the source and mode of genesis of
the flesh-worm (1860). Leuckart likewise did good service by disproving
the erroneous views that had been put forth by Küchenmeister. Lastly,
all these brilliant results culminated in the clinical observations
of Zenker, who opened out a new epoch in the history of trichinal
discovery. Professor Zenker was the first to detect the young in the
act of migration, and he likewise primarily demonstrated the fact that
the larval parasites were capable of producing a violent disease in the
human body.

[Illustration: FIG. 35.--Sexually mature _Trichina spiralis_; male.
After Leuckart.]

Never in the history of biological science have more valuable issues
followed the method of experiment upon animals. Not only has human life
been thus saved, but animal life also. State-medicine and sanitation
have received an immense impulse. The good that has already resulted
is simply incalculable; nevertheless, in the eyes of a set of ignorant
fanatics who infest this country, all experiments “involving cruelty
to animals” ought to be prevented at any cost. The further progress of
biological science in England has hereby sustained a severe check.

The _Trichina spiralis_ in its sexually-mature state is an extremely
minute nematode helminth, the adult male measuring only the 1/18th of
an inch, whilst the perfectly developed female reaches a length of
about 1/8″. The body is rounded and filiform, usually slightly bent
upon itself, and rather thicker behind than in front, especially in
the males. The head is narrow, finely pointed, unarmed, with a simple,
central, minute oral aperture. The posterior extremity of the male is
furnished with a bilobed caudal appendage, its cloacal or anal aperture
being situated between these divergent appendages. The penis consists of
a single spicule, cleft above, so as to assume a V-shaped outline. The
female is stouter than the male, bluntly rounded posteriorly, having the
genital outlet placed far forward, at about the end of the first fifth
of the long diameter of the body. The eggs measure 1/1270″ from pole to
pole. The mode of reproduction is viviparous.

[Illustration: FIG. 36.--Larval Trichina coiled within its capsule.
After Bristowe and Rainey.]

As commonly observed in the human body our young Trichinæ appear as
spirally-coiled worms in the interior of small, globular, oval, or
lemon-shaped cysts, which latter appear as minute specks scarcely
visible to the naked eye. These specks resemble little particles
of lime, being more or less calcareous according to the degree of
degeneration which their walls have undergone. In shape and general
aspect they are not altogether unlike the eggs of certain nematoid
worms, but their size alone sufficiently distinguishes them. They
measure on an average 1/78″ in length by 1/130″ in breadth. The
organised capsules are not essential to the further development of
the parasite, and are rather to be regarded as abnormal formations,
or rather, perhaps, as products resulting from an effort of nature to
protect and thus prolong the life of the occupant. They are frequently
altogether wanting. The capsuled Trichinæ measure 1/23″ in length by
about 1/630″ in breadth. When fully formed they not only exhibit a
well-marked digestive apparatus, but also reproductive organs, which are
often, indeed, sufficiently developed to determine the sex.

Notwithstanding the large number of experiments that have been more
or less recently made by investigators, little or nothing has been
discovered calculated to disturb the conclusions set forth by Leuckart,
who writes as follows:--“(1) _Trichina spiralis_ is the juvenile state
of a little round worm, previously unknown, to which the generic title
of Trichina must remain attached. (2) The sexually mature Trichina
inhabits the intestinal canal of numerous warm-blooded animals,
especially mammalia (also of man), and constantly in great numbers.
The duration of its life extends from four to five weeks. (3) At the
second day after their introduction the intestinal Trichinæ attain
their full sexual maturity. (4) The eggs of the female Trichinæ are
developed within the uterus of the mother, into minute filaria-like
embryos, which, from the sixth day, are born without their egg-shells.
The number of young in each mother-worm is at least from ten to fifteen
thousand. (5) The new-born young soon after commence their wandering.
They penetrate the walls of the intestine and pass directly through
the abdominal cavity into the muscles of their bearers, where, if the
conditions are otherwise favorable, they are developed into the form
hitherto known. (6) The directions in which they proceed are in the
course of the intermuscular connective tissues. (7) Only the striped
muscle (that of the heart excepted) contains Trichinæ. The majority of
the wandering embryos remain in those sheathed muscular groups which
are nearest to the cavity of the body, especially in those which are
smaller and most supplied with connective tissue. Speaking generally,
their number decreases with the distance from the abdomen, being,
however, more numerous in the anterior half of the body. (8) The embryos
penetrate into the interior of the separate muscular bundles, and here
already, after fourteen days, acquire the size and organisation of the
well-known _Trichina spiralis_. (9) Soon after the intrusion of the
parasite the infested muscular fibre loses its original structure, the
fibrillæ collapse into a finely granular substance, whilst the muscular
corpuscles change into oval nucleated cells. (10) The infected muscular
bundle retains its original sheathing up to the time of the complete
development of the young Trichinæ, but afterwards its sarcolemma
thickens, and begins to shrivel at the extremities. (11) The spot
inhabited by the rolled-up parasites is converted into a spindle-shaped
widening, and within this space, under the thickened sarcolemma, the
formation of the well-known lemon-shaped or globular cysts commences by
a peripheric hardening and calcification. This degeneration commences
several months after the wandering. Immature muscle-Trichinæ are not
capable of producing infection. (12) The migration and development of
the embryos also take place after the transportation of impregnated
Trichinæ into the intestines of a new host. (13) The further development
of the muscle-Trichinæ into adult animals is altogether independent
of the formation of the calcareous shell, and occurs as soon as the
former have reached their completion. (14) Males and females are
already recognisable in their larval state. (15) The immigration of the
Trichina-brood in masses produces very grave or even fatal consequences,
such as peritonitis (from the embryos perforating the intestinal walls),
pain, and paralysis (resulting from the destruction of the infected
muscular fibres). (16) The infection of man occurs especially through
swine. (17) The muscle-Trichinæ are so capable of resistance that they
are by no means in all cases destroyed by the ordinary methods of
roasting, cooking, pickling and smoking. (18) As a rule, swine obtain
Trichinæ from rats, to which latter we also as the natural bearers have
to convey them. Microscopic examination of flesh is, therefore, urgently
recommended as a public preventive against all danger from Trichinæ.”

[Illustration: FIG. 37.--Immature female Trichina from muscle. After
Leuckart.]

As a summary the above conclusions are well nigh exhaustive; but whilst
I purposely avoid entering into mere clinical details, there are points
of hygienic interest to which I must allude. Thus, as regards the number
of larval Trichinæ in any one “bearer” at a time, this, of course, must
be extremely variable, but it may amount to many millions. In one of
the cats on which Leuckart experimented, he estimated a single ounce of
its muscle-flesh to harbour no less than 325,000 Trichinæ. I find that
a relatively similar degree of infection in an ordinary human “bearer”
would yield thirty millions. In the case of one of my own experimental
animals, a pig, I reckoned that there were at least sixteen millions
of Trichinæ. The larvæ were about ten months old and enclosed within
perfectly formed capsules; nevertheless, the animal had never displayed
any symptom of irritation. In a trichinised human subject, examined by
Dr Thudichum, it was estimated that 40,000,000 parasites were present.
My own estimate, calculated from specimens of muscle obtained from the
same case, gave 100,000,000 as the approximate number of worms present.
In the only outbreak of Trichinosis occurring in England, details of
which will be given further on, I found that the flesh of the hog that
had caused the local endemic contained upwards of 80,000 Trichinæ to
the ounce. The consumption of a pound of such flesh would be capable of
producing a collective progeny of something like 400,000,000 within the
human “bearer.”

In the year 1865 I conducted a series of experiments upon upwards of
a score of animals, including seven birds, the latter all yielding
only negative results. So far as muscle-Trichinæ were concerned my
experiences accorded with those of Professors H. A. Pagenstecher
and C. J. Fuchs, at the Zoological Institute in Heidelberg. These
experimenters found that the ingested muscle-Trichinæ acquired sexual
maturity within the intestinal canal of their avian “hosts;” but
they never found young Trichinæ in the muscles of the birds, nor did
they perceive any evidences of an attempt on the part of the escaped
embryos to effect a wandering or active migration on their own account.
Clearly, if the bird’s intestinal canal were a proper territory for the
residence of sexually mature Trichinæ, we should have found abundance
of wandering non-encapsuled flesh-worms and also sexually-immature
muscle-Trichinæ enclosed in well-formed capsules. Not a few persons
still entertain the notion that Trichinæ are liable to infest all kinds
of warm-blooded, and even also many kinds of cold-blooded animals, such
as reptiles and fishes. Certain nematodes found in earth-worms have
been described as Trichinæ; and consequently, pigs and hedgehogs were
said to become trichinous through eating these annelids. The minute
flesh-worms described by Bowman from the muscle of the eel are not true
Trichinæ, any more than the somewhat similar parasites which Eberth
found to infest the muscles of the frog. The same may also be said of Dr
Salisbury’s urinary Trichinæ, which are the larvæ of _Filaria Bancrofti_.

Deducting the seven birds, and also six other animals where no
examination after death was possible, I ascertained the result of
my worm-feedings in sixteen instances. Nine of the experiments were
entirely successful, the infected animals comprising four dogs, two
cats, one pig, one guinea-pig, and a hedgehog.

Carnivorous mammals, especially those subsisting on a mixed diet, are
the most liable to entertain Trichinæ, but it is quite possible to rear
them in herbivora. Thus, Pagenstecher and Fuchs succeeded in rearing
muscle-Trichinæ in a calf, and they found three female intestinal
Trichinæ in a goat, but apparently no muscle-flesh-worms, although
twenty-seven days had elapsed since the first feeding with trichinised
rabbit’s flesh. In three sheep on which I experimented no trace of
Trichinæ could be found. There is no practical need for any further
experiments on herbivora, for it is quite clear that, in their natural
state, herbivorous mammals can seldom have an opportunity of infesting
themselves, whilst the reverse is the case with swine, carnivorous
mammals, and ourselves. Because many quadrupeds become trichinous, it
does not follow that all mammals are liable to be infested. In the case
of most parasites we find the species limited to a larger or smaller
number of hosts. On the other hand, in not a few cases, the range of the
entozoon is limited to a single territory or host.

In conducting the experiments above mentioned I was assisted by
Professors Simonds and Pritchard, of the Royal Veterinary College. As
they were the only researches conducted on any considerable scale in
England, I subjoin a few details of them. Dr Thudichum’s experiments
were, I believe, confined to rabbits.

_Exps._ 1 and 2.--On the 15th of March, 1865, an ounce of flesh
containing Trichinæ was administered by myself to a black bitch. The
dog being destroyed five days subsequently, neither intestinal nor
muscle-Trichinæ were discovered. It was thought that the dog had thrown
up the bolus, which was strongly saturated with chloride-of-zinc
solution. The bolus consisted of a portion of the _pectoralis major_
of a subject brought to the dissecting-room at the Middlesex Hospital.
The cysts were highly calcified, but the majority contained living
embryos, which were quite unaffected by the zinc solution injected into
the body to prevent decomposition. At the same date a small white puppy
was experimented on and examined with precisely the same results. In
either case it was too early to expect muscle-flesh-worms to have become
developed.

_Exp._ 3.--Half an ounce of the same trichinous human flesh was given
(at the same date) to a black-and-tan puppy reared at the Royal
Veterinary College, a second “feeding” being administered on the 21st of
March, or six days after the first. In this case Mr Pritchard, who fed
the animal, took the precaution to chop the muscle into small pieces,
and to mix it with other food, in order that the flesh might be the more
readily retained in the stomach. The puppy was not destroyed until the
15th of the following June, when, on examination, numerous encysted but
non-calcified muscle-Trichinæ were found in all the voluntary muscles
subjected to microscopic scrutiny.

_Exp._ 4.--An ounce of the same flesh was given to a dark-colored pig on
the 15th of March, and again on the 20th, several other “feedings” being
also administered during the month of April, 1865. It was destroyed on
the 16th of May, but no Trichinæ were detected.

_Exp._ 5.--An ounce of the same human muscle-flesh administered to a
small sheep (which was subsequently killed on the 29th of June) also
produced negative results.

_Exps._ 6 and 7.--“Feedings” were at the same time administered to a rat
and mouse. The mouse died on the 2nd April, when I examined its muscles
without success. On the following day the rat unfortunately made its
escape, but whether trichinised or not cannot be said.

_Exp._ 8.--An ounce of trichinous human flesh was given to a donkey, in
the form of “balls,” on the 20th of March; and during the month of June
four other separate “feedings” with trichinous dog’s flesh were also
administered. The animal was removed from the College without the result
being ascertained.

_Exp._ 9.--From the 15th to the 20th March, 1865, inclusive, three small
Trichinæ “feedings” were likewise administered to a guinea-pig. This
little animal was not destroyed until the 15th of the following June,
when a positive result was obtained. The _pectoralis transversus_ and
other muscles were found to harbour a considerable number of encysted
Trichinæ.

_Exp._ 10.--On the 20th March, and again on the 21st (1865), “feedings”
from the same human subject were administered to a hedgehog. On the 26th
of April the animal seemed to be attacked with symptoms of Trichinosis.
It refused food, kept its head extended, and the eyelids closed. On the
27th it appeared much worse, and on the morning of the 28th it was found
dead. On the 29th I examined the flesh, and found abundance of living
Trichinæ in the muscles. The capsules were very thin and transparent. A
few days later Mr Simonds also examined the flesh, and confirmed this
result.

_Exps._ 11 and 12.--Two chickens were fed, on the 21st of March, with
the same material. One of the birds died on the 24th, when I examined
the intestines and detected one or two very minute nematodes, which,
at the time, I believed to be imperfectly developed Trichinæ, but
subsequently saw reason to alter my opinion. The other bird died on the
3rd of April, and certainly contained no muscle-Trichinæ.

_Exp._ 13.--On the 22nd and 23rd of March “feedings,” amounting to an
ounce of flesh in all, were given to a mole. This animal was returned
to the care of Mr Charles Land, who had previously sent it to the
Veterinary College. He subsequently reported that, after observing the
mole to be “working” for two or three days, he lost all trace of it, and
concluded that it had either escaped or was dead.

_Exp._ 14.--On the 1st and 2nd of May portions of the left fore
extremity of the hedgehog (in which we had successfully reared Trichina
from the Middlesex-Hospital subject) were offered by Mr Simonds to a
cat. It ate the flesh very readily, consuming the entire limb. On the
15th of the following June the cat was killed, when living Trichinæ were
found within all the muscles which we examined.

_Exp._ 15.--At the same dates a young terrier dog was similarly treated,
but did not take the “feeding” so readily. In this case the left
hind extremity of the hedgehog was employed, and what was not eaten
voluntarily was forcibly introduced. On the 1st of June the dog was
attacked with “distemper,” and died on the 8th of the same month. On
examination we found several living Trichinæ in the _sterno-maxillaris_
and other muscles. Some of the parasites were encysted.

_Exp._ 16.--From the 9th to the 12th of June inclusive four separate
worm-feedings with the flesh of the trichinised terrier-dog were
administered to a crow. The bird was killed some months afterwards and
sent to me for examination. Its muscles were entirely free from Trichinæ.

_Exp._ 17.--From the 9th to the 17th of June inclusive seven separate
worm-feedings were administered to a pig. One of the “feedings” was
with the trichinised guinea-pig’s flesh, the others from the dog. This
animal was not destroyed until the 4th of April, 1866, when all the
muscles which I examined were found extensively infested with Trichinæ.
There were probably not less than 16,000,000 present, all being alive
and enclosed within perfectly-formed capsules, none of which latter
exhibited any traces of calcareous deposition.

_Exp._ 18.--Four separate feedings with trichinous dog’s flesh were
likewise, at the same dates as the foregoing, administered to a rat.
This experimental animal, however, like the one previously mentioned,
contrived to make its escape. I fear it was well trichinised.

_Exp._ 19.--About the same date trichinous “feedings” were given to
a black puppy (bred at the Veterinary College). The dog was killed
on the 18th of August, 1866, having also been made the subject of an
echinococcus-feeding, when I found abundance of encysted Trichinæ within
the voluntary muscles.

_Exp._ 20.--Four separate worm-feedings with the flesh of the
trichinised guinea-pig were given to a sheep on the 15th, 16th, 17th,
and 19th days of June, 1865. The experimental animal was destroyed on
the 29th of the same month, but the result was negative.

_Exps._ 21 and 22.--“Feedings” with the guinea-pig’s flesh--four in the
one case and three in the other--were also administered by Mr Simonds
(from the 15th to the 19th of June, inclusive) to a chicken and goose
respectively. These birds were destroyed some months afterwards and
sent to me for examination, but the most careful scrutiny failed to
detect any Trichinæ within their muscles. The goose was cooked and eaten
without the slightest hesitation. The chicken I found too tough for
consumption.

_Exp._ 23.--On the 28th of March, 1866, I obtained a small quantity
of muscle from a highly trichinised German subject, who died from the
effects of an accident at the London Hospital the day previous. The case
was fully reported by Dr Thudichum in a new journal, called ‘Scientific
Opinion’ (No. 4, April 25th 1866, p. 55). During the same day (at 2.30
p.m.) I fed a dog with part of this human flesh. On the morning of the
31st I killed the dog, and examined the intestinal canal (at 11.30
a.m.), which revealed the presence of sexually-mature living Trichinæ.
The males (of one of which I retain an accurate figure) displayed the
characteristic bilobed caudal appendage, leaving no doubt as to their
source and nature. I have mentioned the precise time of the experiment,
in order to show that a period of sixty-nine hours proved amply
sufficient for the development of the young muscle-flesh-worms of the
human subject into the sexually-mature adult Trichinæ of the dog.

_Exp._ 24.--With another portion of this human flesh (taken from the
muscles of the tongue) in which the Trichinæ were extraordinarily
abundant, I fed a cat. In about ten days the animal showed the most
marked symptoms of trichinosis. It refused to eat; the eye lost its
lustre; the body became very thin, and I thought the animal would die.
By very great care, keeping it warm before the fire, and subsequently
inducing it to take a little milk, the creature improved, gained flesh,
and eventually recovered. About three months afterwards I destroyed
this cat, when on examining the _panniculus carnosus_, _latissimus
dorsi_, and other superficial muscles, I found great quantities of
well-developed, capsuled Trichinæ. Although the animal had swallowed
scarcely a quarter of an ounce by weight of the infested flesh, yet
thousands of parasites had been propagated and dispersed throughout
its muscular system. In this way the helminthiasis nearly proved fatal
to my cat. As has been already stated, Dr Thudichum, who I believe had
an opportunity of examining the corpse of this trichinised German,
estimated the number of parasites in his body at 40,000,000. I do not
think this estimate likely to be exaggerated, for if all the flesh had
been infested to the extent I found to obtain in respect of the muscles
of the tongue, I believe 100,000,000 would have been nearer the mark.
In places the point of a needle could scarcely be thrust between the
capsules, so closely were they agglomerated.

_Exp._ 25.--From the 19th to the 25th of April, 1866, inclusive, daily
administrations of trichinous pork, in the form of bolus, were made to
a sheep by Mr Pritchard. The Trichinæ were obtained from one of our
experimental animals at the Veterinary College, about two ounces of the
flesh being given at each feeding. The flesh of this sheep (destroyed in
the following November) failed to give any indication of the presence of
parasites.

_Exps._ 26 and 27.--About the same time, and occasionally at intervals
extending over a period of five weeks, Mr Pritchard also fed two young
fowls with the same trichinous pork. Towards the close of October, 1866,
both birds died, when Mr Pritchard carefully examined the flesh of them,
but failed to find any trace of Trichinæ.

_Exps._ 28 and 29.--From April 2nd to the 9th of the same month, 1866,
inclusive, feedings with trichinous pork were likewise given to two
dogs. These animals were destroyed and examined by Mr Pritchard in
November, 1866, but the result appears to have been negative.

It is perfectly certain that the infection of man by Trichina is
invariably due to the ingestion of verminiferously diseased meat, and
as remarked in my ‘Lectures,’ whenever the parasites are taken in large
numbers unpleasant symptoms soon show themselves in the infested person.
There is, first of all, restlessness, loss of appetite, and more or
less prostration. This is succeeded by rheumatoid pains in the limbs,
with the frequent accompaniment of considerable swelling. The pain is
not situated in the joints, but in the intermediate soft parts. In
severe cases the limbs are drawn up and half bent, as in instances of
severe and continued cramp. Sometimes the suffering is excruciating and
unbearable, patients having been known to request the surgeon to put
an end to their lives. In the worst forms of the malady death rapidly
ensues from diarrhœa and exhaustion. If the parasites have gained
admission to the muscles all hope of destroying them is at an end; but
if a person suspects himself to have eaten diseased or trichinised meat
he should lose no time in seeking professional assistance, seeing that
the administration of suitable anthelmintics might be the means of
saving his life, whereas a few days’ delay would probably prove fatal.
So long as the worms remain in the stomach or intestinal canal they can
be got rid of, but when once the trichinal brood have invaded the flesh
then they cannot be expelled. As remarked in my ‘Entozoa,’ it is easy
to perceive that although, in the majority of instances, Trichiniasis
does not cause death, yet the percentage of fatal cases is by no means
insignificant.

The notion that particular breeds of swine are more liable to be
infested than others is absurd, since infection must be due to the
facilities offered for swallowing garbage, especially dead rats.
According to Drs Belfield and Atwood 8 per cent. of slaughtered American
swine contain Trichinæ. In infested hogs they found from 35 to 13,000
parasites in a cubic inch of muscle, and by repeated feedings they
succeeded in rearing about 100,000 Trichinæ in the body of a rat.

In regard to the disease in man let us glance at the phenomena that
presented themselves in Plauen, a town of Central Saxony. Drs Böhler
and Königsdörffer, who first saw this disease and treated it, state,
according to Leuckart, that “the affection began with a sense of
prostration, attended with extreme painfulness of the limbs, and, after
these symptoms had lasted several days, an enormous swelling of the face
very suddenly supervened. The pain occasioned by this swelling and the
fever troubled the patients night and day. In serious cases the patients
could not voluntarily extend their limbs, nor at any time without pain.
They lay mostly with their arms and legs half bent--heavily, as it were,
and almost motionless, like a log. Afterwards, in the more serious
cases, during the second and third week, an extremely painful and
general swelling of the body took place; yet, although the fifth part of
all the patients were numbered amongst the serious cases, only one died.”

Satisfactory as it may be to note the numerous recoveries which take
place, this circumstance is very much marred by the fact that a large
proportion of the patients suffer the most excruciating agony. In the
main it will be observed that Böhler’s and Königsdörffer’s experience,
as recorded by Leuckart, corresponds very closely with that given by
other observers. The symptoms, moreover, are very similar to those
produced in the original case published by Zenker. In this case, which
occurred in the Dresden Hospital (1860), the patient was a servant
girl, aged twenty, and the principal symptoms were loss of appetite,
prostration, violent pains, contraction of the limbs, and finally œdema,
which, in association, perhaps, with a certain amount of pneumonia,
terminated her career within a period of thirty days. The post-mortem
appearances showed that the larval Trichinæ were the cause of death.
The intestinal canal contained numerous sexually-mature worms.

The effects produced by Trichinæ on animals are similar to those
occasioned in man. The phenomena were summarised by Davaine (in the
journals quoted below) in 1863 as follows:

“The first phase is characterised by intestinal disorder, produced by
the development of the larvæ in large numbers, and their adhesion to
the mucous membrane of the intestine. In this stage M. Davaine has seen
rabbits die with intense diarrhœa; one of two cats which he fed with
trichinised meat had diarrhœa for at least a fortnight, but survived. Of
five or six rats fed on a similar diet, one only, which was pregnant,
died of diarrhœa, after abortion, on the eighth day. According to M.
Leuckart, the passage of the embryos of Trichinæ through the intestinal
walls sometimes produces peritonitis. This intestinal phase often
becomes blended with the next; it may be relieved by the expulsion of
the worms by means of the diarrhœa, or may cease with the natural death
of the worms.

“The second stage presents general symptoms--muscular pains, &c. These
phenomena are dependent on the introduction of the Trichinæ into the
muscles; they rapidly acquire their maximum intensity, and have not a
long duration. The appearance and duration of this stage are in complete
relation with the development and length of sojourn of the Trichinæ
in the intestines; in fact, in this entozoon, oviposition is not slow
and of long duration, as in many nematoid worms; the genital tube is
rapidly formed, and the ova, in its whole length, are developed almost
simultaneously, so that the embryos, arriving soon at maturity, are at
once thrown out in large numbers into the intestine, and the mother
Trichina dies exhausted. If it be remembered that the embryos do not
escape before the eighth day, that a certain number of days are required
for their arrival in the muscles, and that new ones are not produced
after six or seven weeks, it will be understood that the first symptoms
of this stage can scarcely appear until the end of a fortnight after
ingestion of the diseased food, that they must continue four or five
weeks, and that after this they may disappear. This course of events is
observed in animals; and in man the symptoms of this stage have shown
themselves and become aggravated from the third to the sixth week after
infection. Most animals die during this stage; rabbits rarely survive;
rats, on the contrary, generally resist it.

“If the animals do not die of the general symptoms or local disturbances
proper to these two stages, the inflammatory symptoms cease, respiration
becomes natural, and order is re-established. But, in some cases, the
number of cysts formed in the muscles are sufficiently great to impede
them in the proper exercise of their functions, and hence arises general
debility, a kind of consumption which persists or becomes aggravated,
and the animal dies of marasmus. M. Davaine has noticed this in rabbits,
but especially in a rat.

“Recovery from these phases of trichinal infection may be apparently
perfect. A rabbit which M. Davaine kept during five months became large
and fat, although it had a large number of Trichinæ in its muscles;
a rat which had had these entozoa in considerable numbers during six
months was, to all appearance, in good health. Hence he concludes that
the Trichinæ produce symptoms only when they are in the intestinal
canal, and when they are entering the muscles. Having become lodged in
their cysts among the muscular fibres, they may remain harmless for an
indefinite time. In every case except one, down to 1859, Trichinæ have
been found in the bodies of persons who have died of disease (generally
chronic) or by accident; or in the dissecting-room, in bodies regarding
which the previous history could not be obtained. In most cases the
cysts contained a cretaceous or fatty deposit, showing that they had
probably existed several years.

“The observations which have been made on the human subject, in regard
to the symptoms caused by Trichinæ, show that they belong, as in
animals, to the initial period of infection. They consist in intestinal
and in muscular lesions; the latter coincide with the entrance of the
parasite into the muscles, and are truly traumatic. In Zenker’s case
the intestinal symptoms were swelling and pain; in a case described
by Friedreich diarrhœa was present. In all cases the most remarkable
symptoms were violent rheumatoid pains in the muscles, not in the
joints, which were considerably aggravated by attempts to extend the
half-bent limbs. The other symptoms have been variable, but have had a
strong resemblance to those of typhoid fever. In several cases there has
been abundant sweating; and in one there was a very remarkable miliary
and furuncular eruption. The animal heat was diminished in Friedreich’s
case; and in those observed in Voigtland by Freytag the temperature
never exceeded 102° Fahr.

“The progress, duration, and severity of the disease in man are in
relation to the number of Trichinæ taken into the digestive canal. Of
sixteen patients observed at Plauen by Drs Böhler and Königsdörffer,
eight, who were moderately affected, recovered in a month; four, more
severely diseased, were ill two months; of four others, one died with
ascites and colliquative diarrhœa at the end of two months, and three
recovered slowly at the end of three or four months. Recovery does not
imply the death of the Trichinæ, it follows their enclosure in cysts.

“The diagnosis of trichinal infection has several times been made in the
living human subject by removing a portion of muscle. M. Davaine thinks
it probable that, during the first six or eight weeks of the disease,
the diagnosis may be confirmed by searching for adult Trichinæ in the
alvine evacuations, produced naturally or by means of a purgative.

“The prophylactic treatment consists simply in the avoidance of
uncooked meat. The medicinal treatment must vary with the stage of
the disease. At first, attempts must be made to expel the parasites
from the intestines by purgatives and anthelmintics. Which amongst
the latter is the most energetic is not yet determined. Calomel is,
perhaps, M. Davaine thinks, the best. After six or eight weeks all
treatment directed towards the intestines is superfluous. It is scarcely
probable that any substance will act on the larvæ disseminated through
the muscles. Friedreich has recommended picronitrate of potash; but, in
the case in which he used it, live Trichinæ were found in the muscular
tissue after the patient was considered to be cured.”

In regard to the possibility of curing trichiniasis by the
administration of drugs which should act as trichinacides upon the
parasites in the condition of flesh-worms, the absurdity of the proposal
only equals that which was made in reference to the destruction of
hydatids by the administration of kamala. As has been shown in the
record of my first experiment the flesh of a trichinised corpse may be
thoroughly saturated with a strong solution of chloride of zinc, and yet
the worms will remain quite unaffected.

In reference to the dangers arising from the consumption of diseased
meat, Professor Gamgee has very cogently put two questions:--“Did
Moses know more about pigs than we do?” “Was it a knowledge of the
parasitic diseases of swine and man that led Moses to condemn pork as
human food?” Mr Gamgee answered both questions negatively, thus:--“The
wisdom of the Mosaic law can only be justly estimated with a knowledge
of the accidents arising in warm countries from eating pork throughout
long and hot periods of the year; and there is no doubt that the direct
evil results, as manifested by human sickness, led to the exclusion of
pork from the list of Israelitish viands. The masses of measly pork
which may be seen hanging from the butchers’ stalls in Southern Europe
prove that the long-legged swine which hunt the forests for acorns, and
rove about to pick up all kinds of offal, are often unfit for human
food, and that they were so to no less extent in the land of Israel is
probable.” As supplementing Professor Gamgee’s argument, I may remark
that, if Moses had been furnished with special knowledge beyond that of
his contemporaries, he would not, in the matter of meat-parasitism, have
confined his restrictions to pork. Had he possessed any knowledge of
measly beef, he would not have spared the ox on the ground that although
“it divideth the hoof, yet it cheweth the cud.” As regards home-reared
animals, Professor Gamgee cogently remarked: “It is interesting to
observe that parasitic maladies in the pig specially abound in that
section of the United Kingdom where swine live most amongst human
beings. The Yorkshire and Berkshire pigs, in their native counties
enclosed in the farmyards of their breeders, are free from worms which
are likely to live in the body of man. The Irish pig is the one most
commonly injured by entozoa, and the reason for this is evident when
we know how much the cottager relies on rearing a porker which is
permitted the free range of house and road, where every description of
filth is devoured, charged with the ova of parasites expelled by man
or some of the lower animals.” He also adds: “The conditions under
which we live in the British isles are certainly much less favorable to
the propagation of worms; but we disregard, in our ignorance, the most
common precautions to protect ourselves from loathsome diseases, and not
only permit dogs to eat any kind of offal in and around slaughterhouses,
but sanction the existence of piggeries where all kinds of garbage,
charged with worms or their eggs, are daily devoured by swine. The
majority of germs calculated to engender parasites are to be found
in abundance in the contents of the alimentary canal of human beings
and domestic quadrupeds. If pigs are permitted to eat these, as in
Ireland or in many British piggeries, we must expect hams, bacon, and
pork sausages to be charged with the embryonic forms of human entozoa.
Whereas in Iceland the _dog_ is the victim of human negligence, and _en
revanche_ the cause of human disease, in the British isles the _pig_
holds this unenviable position. We have good reason to believe, with
Moses, that the pig is an unclean beast; but without discarding him from
the scanty list of animals to be eaten, it is evident that we can purify
the race of swine, and thus prevent human as well as porcine maladies.”

On the authority of Rupprecht, as quoted by Davaine, I append a list of
the principal epidemics observed in Germany during the first six years
immediately following the discovery of trichinosis:

1. Two slight epidemics in 1860 in the Island of Rügen; 10 to 20
patients (Dr Landois).

2. An epidemic at Stolberg, 1860 (Dr Fricinus). The number of
trichinised persons was not stated with certainty.

3. Five epidemics during five summers, 1858 to 1862, at Magdebourg. The
number of patients was 300, two only died (Dr Sendler).

4. An epidemic at Plauen in 1862, 20 patients (Böhler).

5. Gusten, 1861, 40 cases, all cured (Fränkel).

6. Epidemic in the Province of Armsted (Mansfeld), 1861, 8 patients.

7. Hettstädt, January and March, 1862, 8 to 10 patients.

8. Blankenburg, 1862, 278 cases, 2 deaths.

9. Calbe (Prussia), 1862, 38 cases (9 men, 25 women, 4 children), 8
deaths (Dr Simon and Dr Herbst).

10. Burg, in Magdebourg, 1863, 50 patients, 10 deaths (Dr Klusemann).

11. Quedlinburg, 1863, 9 patients, 1 death (Dr Behrens).

12. Plauen, 1863, 21 patients (Königsdörffer).

13. Falkenstein, 1863, 4 patients (Drs Bascher and Pinter).

14. Posen, August and September, 1863, 37 patients (Dr Samter).

15. Hamburg, 1863, 2 patients (Dr Tüngel).

16. Blankenburg, 1863, 32 patients, 2 deaths; new cases in 1864 (Dr
Scholz).

17. Hettstädt (Prussian-Saxony), October, 1863, 158 patients, 27 deaths
(Rupprecht).

18. Eisleben, December, 1863, and January, 1864, 18 cases, no deaths.
This result was attributed to the employment of phosphoric acid
(Rupprecht).

19. Hettstädt, February and March, 1864, 8 patients, no deaths. Two
cats were also attacked, one of which died. Nearly 50,000 Trichina were
counted in an infected leg of pork (Rupprecht).

20. Quedlinburg, 1864, 120 patients, 2 deaths; benzine was employed (Dr.
Wolf).

21. Hettstädt, January, 1865, 15 patients (Rupprecht).

22. Berlin, 1864, 3 cases (Dr Cronfeld). Several butcher boys (Frischer).

23. Leipzig, 1864, 14 patients, 2 deaths; 4 were infested after having
eaten raw beef hashed on a block which had previously received the flesh
of a trichinised hog (Dr E. Wagner).

24. Potsdam, 1864, 5 slight cases (Dr Mollendorf).

25. Celle (Hanover), 1864, 8 patients (Dr Scheller and Dr Baring);
Trichina proven in the pork by Gerlach. In 1855, 12 Trichina (?)
patients were treated by Schuchart.

26. Hedersleben, 25th October, 1865, a pig was killed and sold; on the
28th the malady appeared amongst the workmen; 350 patients, 100 deaths.
Of 100 children infected, none died. Trichina found in the autopsies (Dr
F. Kratz).

Dr Davaine also adds the following outbreaks:

In Massachusetts, 1867, 6 patients from having eaten raw ham, 1 death
(‘Medical Times,’ 20th April, 1867, p. 431).

Ravecchia (Bellinzona), 1868, 5 patients, 4 deaths (Dr Zangger in
_Landbote_ of Winterthur).

Up to a comparatively recent date no case of trichinosis had been
recognised in England during the life of the victim. As regards
diagnosis, what was happening every day on the Continent was utterly
unknown here. Whilst, however, not a single instance of Trichina-disease
had been observed by British physicians in actual practice, as many as
thirty or forty instances had occurred where the parasites in question
had been found post mortem. I had myself examined the trichinised flesh
taken from a dozen of these corpses, but in no instance had the faintest
suspicion of trichinosis been entertained during life. The circumstances
attending the only outbreak of trichiniasis that has been witnessed in
England are very interesting. In the month of April, 1871, I received
from Dr W. L. Dickinson, of Workington, Cumberland, specimens of pork
which he requested me to examine; and in complying with his request I
confirmed his opinion that the diseased meat was infested with Trichinæ.
A few days afterwards I announced the discovery in the pages of the
‘British Medical Journal’ for April 22, p. 435. It happened, also, that
at the time I was delivering a course of lectures before the Society
of Arts; consequently, in my second discourse (which was devoted to
the parasites of cattle) I gave full details of the facts that were
obtained. Taking a small portion of the flesh which I judged to be
affected to an average extent I addressed the audience as follows:

“If you calculate from one portion only, you might, if you had stumbled
upon a part which was more infested with parasites than another, be led
to over-estimate the degree of trichinisation. Taking proper precautions
I have calculated that one scruple of this trichinous flesh would give
us 4320 parasites, and two scruples would therefore yield 8640. Without
speaking so precisely to numbers, I do not hesitate to aver my belief
that there are at least 5000 of these parasites inside this small
piece of ham. The number is probably close upon 8640. In one drachm
that would give us 12,000, and in an ounce 103,000, according to the
old apothecaries’ weight. If, however, we calculate according to the
ordinary weight used by butchers, we should say that one ounce contains
437-1/2 grains of meat, and therefore the number of parasites in one
ounce would be 85,000. Thus, in one ounce of meat from this particular
pig you have 85,000 Trichinæ, calculated at the rate of 200 in the
grain, for I have purposely cut off the odd numbers. You may say, if a
person can survive 18, 20, 30, or 40 millions, he would not take much
harm from eating a piece of flesh containing only 8640 parasites. Such
a portion, however, would be quite sufficient to make any one of us
extremely uncomfortable were we to eat it, for supposing its contained
parasites to be alive, it might prove dangerous to life. Why? The
explanation is this:--Half of those 85,000 parasites, at the very least,
will, in forty-eight hours after ingestion, have become fully-developed
females; and from each of these 42,000 there will proceed at least
1000 as a brood, so that the entire progeny (and it is they that do
the mischief by their independent migrations through our tissues) will
eventually yield about 42,000,000 entozoa. If we should be so voracious
as to eat a pound of such trichinised flesh, then there would be
400,000,000 as the result of a single meal.

“Having detailed these facts and inferences, I now wish to bring to your
notice some other particulars connected with the Cumberland outbreak.

“Dr Dickinson, of Workington, tells me that he was at first suspicious
that his patients were suffering from fever, but was not quite able to
make out what the disorder was. At length certain symptoms occurred,
which suggested that it might possibly be the German flesh-worm
epidemic making its appearance in this country for the first time,
and, therefore, in view of verifying the facts of the case, he sent
me portions of the flesh of the pig. He describes the symptoms, which
in their character corresponded with those previously recorded as
experienced by persons similarly attacked. Dr Dickinson remarks, towards
the close of his communication, that the victims form a small family
who have carefully reared their own swine. The British farmer is thus
here introduced to us at his own table playing the part of ‘host’--at
her own table, I should say, for, to be more precise, it is a widow,
her daughter, and a man-servant who are suffering. Dr Dickinson informs
me that for two or three weeks before he was called to see them they
had been eating sausages and boiled pork from one of their own home-fed
pigs, which pig, by the way, turns out to have been an old sow. He
brought away some sections of the leaner portions of the flesh for
microscopic examination. You will observe that there can be no mistake
about the source of the food on this occasion. Hitherto, Trichina has
not been observed in our British-fed swine in more than one or two, or
possibly three instances. Therefore it would be very interesting to
ascertain how it happened that this poor pig became trichinised. In my
communication addressed to the ‘British Medical Journal,’ I wrote as
follows:--“Dr Dickinson has at the present time under his care a family
suffering from the so-called flesh-worm disease, resulting from the
consumption of ham prepared from pigs reared by the family themselves.
A portion of ham sent to me swarmed with recently encapsuled Trichinæ.
Dr Dickinson being thus the first person who has diagnosed trichiniasis
in the living subject in England, I hope he may be induced to give us
further particulars.” The editor, in commenting upon this letter, added
a practical point, which I wish especially to bring to your notice. He
says:--‘The subject of parasitic diseases of domestic animals is one
of widespread and increasing interest. It is immediately related to the
irrigation of fields with sewage.’ The editor, of course, made this
statement on independent grounds, and on his own responsibility. If he
had said the subject bears an indirect relation to the sewage question,
he would have said no more than is absolutely true, for, as I shall
take occasion to explain, there is every reason to suppose that certain
forms of parasitic disease may be propagated by means of sewage. In this
connection some of you may be disposed to ask the question:--‘Are there
any sources of comfort to be gathered from the facts?’ Or you may say,
supposing that in future our British swine are not as free from Trichinæ
as they have been hitherto, can we possibly avoid the contingency of
playing the part of host to those creatures? Certainly, I reply, it is
simply a question of properly cooking the food. If these farmers have
not cooked their food at all, or scarcely at all, that will at once
account for their being laid up. I should tell you that the lady and
the daughter are recovering, and that they are convalescent, but the
man-servant is very ill. If, during cooking, the flesh consumed by these
persons had been raised to a persistent temperature of 170° Fahr., then,
doubtless, the ingestion of trichinised pork would have done no harm.
You observe that Dr Dickinson says in his letter that they partook of it
roasted and boiled. Now, few of us are in the habit of eating underdone
pork, although there are other meats that we devour very readily in an
imperfectly cooked state. It must be remembered, also, that although
the exterior may have been subjected to a temperature of 212 degrees,
it by no means follows that the whole of the joint throughout must have
been submitted to that temperature. Under rapid cooking, the centre of a
large joint may remain much below even 140 degrees. If the man-servant
ate only one ounce of the flesh with living Trichinæ in it, he will
probably have at this present moment at least 42,000,000 of these guests
in his muscles. You will ask, ‘Will he recover?’ ‘Yes; if he ate no
more than that.’ If he has eaten 2 oz. thoroughly underdone, depend
upon it he has 80,000,000, and if he has eaten 3 oz. he will have over
100,000,000 of Trichinæ in his muscles. Could he survive if he had eaten
over 3 oz., and thus have 100,000,000 and upwards of these inhabitants?
I think he could. We have evidence on this point from the case in which
I estimated that there were upwards of 100,000,000 of Trichinæ present,
and yet the man survived the attack.

“Incidentally I may remark that in the course of the last twenty years,
although millions of parasites and their eggs have passed through my
hands, I have almost entirely escaped infection. It is something to
know what you are either handling or looking at, because there are many
parasites besides Trichina which are dangerous. There are gregariniform
entozoa residing in meat which we eat every day without any bad
consequences. They are as harmless as cheese-mites. There is no need
to be in the slightest degree nervous about flesh-food, provided it is
properly cooked. I believe there will be no fatal issue in the case of
any of the three individuals just alluded to, but the chief practical
point before us arises out of the fact that we have here, for the first
time in England, an epidemic of trichiniasis. By calling attention to
the subject, it will, to say the least, suggest precautions by which
future epidemics may be avoided.”

The above remarks form the substance of a lecture given on the 24th of
April, 1871. A week later I delivered the third of the Cantor lectures
for that year, when I took occasion to add the following particulars:

“It has been asked whether the so-called muscle-Trichinæ, after they
have arrived at their destination within the flesh of man, are capable
of producing any more unfavorable consequences? The answer is, Certainly
not. In the case of man it would be necessary that his muscles should
be eaten in order for the Trichinæ to become sexually-mature worms;
and in those countries where cannibalism exists, the man-eater would
himself become trichinised, and would certainly deserve his fate. I was
very desirous to follow up the account of this outbreak by inquiries
respecting the particular animal which had been the cause of the
outbreak. I may therefore mention that my informant, Dr Dickinson,
states that the family, including the man-servant, all fed together,
and that they had for upwards of a fortnight eaten daily, and sometimes
twice a day, sausages made from the flesh of the trichinised animal.
And he adds: The meat cut from the ham and flitches, and what is called
the spare-rib, was roasted before the fire or in the frying-pan.
Occasionally it was cooked in the oven. Dr Dickinson ascertained from
the mother that she liked her meat to be underdone, and thus, therefore,
there is very little doubt that the meat was generally undercooked. The
man, a strong labourer, had a good appetite, and would therefore get a
large share. He is improving slowly. Dr Dickinson adds in a postscript,
what is still more to the point, that the sausages would be most likely
undercooked; they would be cooked in the frying-pan, and if only brown
on the outside would be eaten. It is probable that the outbreak was due
therefore to eating underdone meat from this pig, cooked in various
ways, and not alone from the ham itself.”

If the facts connected with this outbreak be honestly faced, it must be
rendered clear to any unprejudiced observer that Dr W. Lindow Dickinson
was the first person to observe, recognise, and treat the Trichina
disorder in this country. No other English, Scotch, or Irish physician
has encountered any similar case. If I lay stress upon this fact it
is because I have learned from Dr Dickinson that another person has
asserted priority in this relation. Sir Dominic Corrigan is stated
to have told a gentleman in the House of Commons, “that he had often
met with trichiniasis in his practice in Dublin,” further averring
that the disease “was quite common in many parts of Ireland.” If Sir
D. Corrigan merely desired it to be understood that he had repeatedly
encountered the Trichina at post-mortem examinations, then there is
nothing surprising in his statement, but if, on the other hand, the
disease itself has been frequently recognised in the living Irish human
subject, one can only express astonishment that hitherto no single
instance of the kind appears to have been recorded either in the public
or professional journals.

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2nd edit., p 732-768.--_Idem_, “Faits et Considerations sur la
Trichine,” ‘Mémoires de la Société de Biologie’ for the year 1862,
tom. iv, ser. 3, 1863; in ‘Gazette Médicale de Paris,’ 1863; in
‘British Medical Journal’ for April 25, 1863; and in my ‘Entozoa,’
p. 349.--_Idem_, “La Trichine” (popular exposition), in ‘Revue des
Deux Mondes’ for May, 1865.--_Dujardin_ (l. c., Bibl. No. 1), p.
24.--_Fiedler_, ‘Virchow’s Archiv,’ 1864.--_Fleckles, F._, ‘Die
Trichinen und die Trichinenkrankheit’ (popular exposition), Prag.,
1866 (quoted by Davaine).--_Friedrich, N._, ‘Virchow’s Archiv,’
1862.--_Fürstenberg_, “Wochenblatt d. Ann. der Landwirthsch., in d.
Königl. Preuss. Staaten,” 1865.--_Gerlach, C._, ‘Die Trichinen,’
1866.--_Idem_, ‘Hannöversche Zeitschrift,’ 1864.--_Hagen_, in
‘Pharmaceutische Centralhalle,’ 1862.--_Henle_, ‘Muller’s Archiv,’ 1835,
s. 526.--_Herbst_, ‘Nachrichten v. d. Georg-Aug. Univ. zu Göttingen,’
1852; ‘L’Institut,’ 1852, p. 135.--_Heschl, R. L._, ‘Ueber Trichinen,
die Trichinenkrankheit und die Schützmassregeln dagegen,’ Gratz, 1866
(quoted by Davaine).--_Kestner_, “Etude sur le Trichina,” ‘Gaz. Méd.
de Paris,’ 1864.--_Klusemann_, “Die Erkrankung durch den Genuss von
Nahrungsmittel aus dem Thierreiche,” ‘Deutsche Klinik,’ 1864.--_Kobelt_,
‘Valentin’s Repertorium,’ 1841.--_Krabbe_, “Husdyrenes Indvoldsorme,”
‘Tiddsskrift for Vet.,’ 1872.--_Kratz_, ‘Die Trichinenepidemie zu
Hedersleben,’ 1866.--_Küchenmeister_, ‘Parasiten,’ 1855.--_Leuckart_,
‘Untersuchungen ueber _Trichina spiralis_,’ 1866.--_Idem_, ‘Die
mensch. Par.,’ Bd. ii, s. 409.--_Idem_, “Die neuesten Entdeckungen
ueber menschliche Eingeweidewürmer und deren Bedeutung für die
Gesundheitspflege,” ‘Unsere Zeit.,’ 1862.--_Lion_, ‘Zur Geschichte,
Therapie, Prophylaxis, und Sanitätspolizei der Trichinen’ (quoted
by Pagenstecher).--_Luschka_, “Zur Naturgeschichte der _Trichina
spiralis_,” ‘Zeitschr. für wissenschaftl. Zool.,’ 1851.--_Meissner_,
‘Zeitschr. f. rat. Med.,’ 1855.--_Idem_, “Ueber Trichinenkrankheit,”
‘Schmidt’s Jahrbücher,’ 1863.--_Ordonez, E. L._, ‘Note sur la
Distinction des Sexes et le Développement de la Trichina spiralis des
Muscles,’ Paris, 1863; and ‘Compt. Rend. Soc. Biologie,’ p. 61, 1863
(quoted by Davaine).--_Pagenstecher_, ‘Verhandl. d. Naturhist.-Med.
Vereins zu Heidelberg,’ 1864.--_Idem_ (und _Fuchs_), ‘Die Trichinen,’
1865.--_Perroncito_, “La _Trichina spiralis_” in ‘Italia. Estr. degli
Annali R. Accad. d’Agric. di Torino,’ vol. xx, 1877.--_Reyher, O._, ‘Die
Trichinenkrankheit,’ Leipzig, 1862.--_Rodet, H._, ‘De la Trichine et
de la Trichinose,’ Paris, 1865 (quoted by Davaine).--_Rupprecht, B._,
‘Die Trichinenkrankheit im Spiegel der Hettstedter Endemie betrachtet,’
Hettstedt, 1864.--_Seidel_, ‘Jenaische Zeitschr. f. Med. u. Nat.’
1864.--_Siebert_, ‘Ueber die Trichinenkrankheit und ihre Vermeidung,’
Jena, 1863.--_Siebold_, art. “Parasiten,” ‘Wagner’s Handwörterbuch,’
1844.--_Simon, G._, “Eine Trichinen-epidemic in Calbe,” ‘Preussische
Medicinal Zeitung,’ 1862.--_Tommasi_, ‘La Trichina spiralis e la
Malattia prodotta da esso,’ Torino, 1863.--_Tüngel_, ‘Archiv von
Virchow,’ xxvii, 3, 421, 1863 (quoted by Davaine).--_Virchow_, ‘Deutsche
Klinik,’ 1859; ‘Comptes Rendus de l’Acad. des Sci.,’ tom. xlix.--_Idem_,
‘Archiv f. Path. Anat. und Physiol.,’ Bd. xviii.--_Idem_, ‘Darstellung
der Lehre von den Trichinen’ (fur Laien und Aerzte), 1864.--_Vogel_,
‘Die Trichinenkrankheit,’ 1864.--_Wagner_, “Eine Trichinenepidemie in
Leipzig,” ‘Arch. der Heilkunde,’ 1864.--_Wunderlich, C. A._, “Sur la
diagnose probable de l’affection trichinale,” ‘Gaz. Méd. de Paris,’
p. 311, 1863; from ‘Wagner’s Archiv der Heilkunde,’ ii, 3, p. 269,
Leipzig, 1861 (quoted by Davaine).--_Zenker_, “Zur Lehre von der
Trichinenkrankheit,” ‘Deutsches Archiv. für Klin. Med.,’ Bd. viii, s.
387.--_Idem_, ‘Virchow’s Archiv,’ 1855 and 1860.

_Trichocephalus dispar_, Rudolphi.--This well-known worm possesses a
long filiform neck, occupying about two thirds of the entire length
of the body. The surface of the skin though smooth to the naked eye
is furnished on one side with a longitudinal band of minute wart-like
papillæ. The tail of the male is curved, and emits at the extremity a
short, tubular penis-sheath, armed with minute retroverted spines. The
tail of the female is straight and bluntly pointed. The eggs measure
1/480″ to 1/447″ in their long diameter. The whipworm infests the cæcum,
and also the upper part of the colon. Upwards of one thousand were found
by Rudolphi in a woman.

The original name of _Trichuris_, given to this worm by Buttner, could
not, of course, be allowed to stand when it became evident that the
so-called tail was in reality the head and neck. The _Trichocephalus_ is
not uncommon in England and Ireland. It is less frequent in Scotland.
On the continent, however, it is so abundant that M. Davaine calculates
that not less than one half of the inhabitants of Paris are infested
by it. From what Dujardin has said it can be scarcely less abundant
in Northern France, for M. Duval, the distinguished director of the
Rennes School of Medicine, supplied that helminthologist with numerous
specimens on various occasions. The worm abounds in Italy and Egypt;
being scarcely less prevalent in the United States. The lamented Mr
Noel, one of my old pupils at the Middlesex Hospital College, brought
me specimens which he found post-mortem on three or four occasions.
Dr Haldane, of Edinburgh, once or twice obtained large numbers
(post-mortem). In Ireland, Bellingham found the worm in eighty-one out
of ninety post-mortem examinations. Mr Cooper, of Greenwich, met with
it, post-mortem, in eleven out of sixteen instances. When treating
patients for tapeworm I have repeatedly expelled the whipworm.

The organisation of _Trichocephalus dispar_ has been investigated
by Dujardin, Mayer, Von Siebold, Eberth, Bastian, and others. Prof.
Erasmus Wilson and myself have carefully studied the anatomy of the
closely-allied whipworm of ruminants (_T. affinis_) which is discussed
in my ‘Entozoa.’

The statement of Küchenmeister that there are no external appendages
in the female _Trichocephalus_ comparable to those known to exist in
the allied _Trichosomata_, is incorrect. Leuckart’s, and especially
Virchow’s, researches disproved Küchenmeister’s and Meissner’s notion
that _Trichinæ_ were the young of _Trichocephalus_. The experiments of
Davaine render it probable that the young get into the human body in
a direct manner. He finds that the eggs undergo no development whilst
yet lodged within the host’s intestines. The eggs are expelled per
anum in the immature condition in which they first escape from the body
of the parent worm. It further appears that, after their expulsion, a
period of six months must elapse before embryonic formation commences.
The fully-developed embryo measures 1/333″ in length, and resembles the
parent to a certain extent.

Whipworms rarely put their bearers to inconvenience; nevertheless, both
human and animal hosts occasionally suffer from their presence. Thus,
Felix Pascal quotes a remarkable and fatal instance of cerebral symptoms
from this cause in a girl of four years of age; and Mr Gibson has
recorded an instance in which these worms produced paralysis and loss
of speech. According to Professor Axe, sheep suffer severely from the
allied species.

BIBLIOGRAPHY (No. 22).--_Bastian, H. C._, “On the Anatomy of the
Nematoids,” ‘Phil. Trans.,’ 1866, p. 545.--_Bellingham, O. B._, “On the
frequency of _Trichocephalus dispar_ in the Human Intestines,” ‘Rep.
of Brit. Assoc., in Dubl. Journ.,’ 1838, and in ‘Med. Chir. Rev.,’
1838; see also Bibliog. No. 33 (and the biography of Bellingham by
Dr Mapother, in ‘Dubl. Jrn. Med. Sci.,’ 1877, p. 471).--_Busk, G._,
“Anat. of _T. dispar_,” ‘Ann. Nat. Hist.,’ vol. vii, 1841.--_Chiaje_,
sul _Tricocephalo disparo_, &c., 1836.--_Cobbold_, ‘Entozoa,’ pp.
69 and 329.--_Idem_, ‘Worms,’ pp. 31 and 67.--_Davaine_, l. c., p.
205.--_Idem_, ‘Compt. Rend.,’ 1858, p. 1217, and ‘Journ. de Physiol.,’
1859, p. 296.--_Dubini_, ‘Entozoografia umana,’ p. 83.--_Dujardin_,
l. c., p. 32.--_Eberth_, “Die Generationsorgane von _T. dispar_,”
‘Sieb. und Köll. Zeitschr.,’ 1860, s. 384.--_Gibson, D._, “On a
Case of Paralysis, with loss of speech, from intestinal irritation
(produced by _T. dispar_),” ‘Lancet,’ Aug. 9th, 1862, p. 139.--_Goeze_,
‘Naturg.,’ s. 112.--_Gurlt_, ‘Path. Anat.,’ p. 350.--_Küchenmeister_,
l. c., s. 235; Eng. edit., p. 321.--_Leidy_, ‘Proc. Acad. Phil.,’
viii, p. 53.--_Leuckart_, l. c., s. 465.--_Mayer_, Sieb. und Köll.
‘Zeitsch. f. wiss. Zool.,’ Bd. ix, s. 367; Bd. x, s. 233, and s. 383,
1858-60.--_Mérat_, ‘Dict. Sc. Méd.,’ p. 560.--_Von Siebold_, ‘Wiegm.
Arch.,’ 1845.--_Wilson, E._, ‘The Veterinary Record and Trans.,’ vol.
ii, p. 47, 1846.

_Filaria Bancrofti_, Cobbold.--The history of the discovery of this
entozoon is second only in interest to that of _Trichina spiralis_. Step
by step the facts have been evolved by a slow process of observation,
and from the data thus afforded a tolerably connected narrative of the
probable life-cycle of this entozoon may now be offered. To place
matters beyond all doubt much remains to be done; yet that which has
been accomplished is, or ought to be, of surpassing interest alike to
the physician, the scientific pathologist, the epidemiologist, and the
philosophic naturalist. In the case of Trichina, Owen’s nomenclature was
most properly allowed to stand; but for reasons stated below I have not
hesitated to employ for this worm, in its adult state, a name differing
from that originally given to the hæmatozoon which turns out to be its
representative larval state. Although the male parasite is at present
unknown, the following characters will in the meantime suffice for a
diagnosis of the species:--Body capillary, smooth, uniform in thickness.
Head with a simple circular mouth, destitute of papillæ. Neck narrow,
about one third of the width of the body. Tail of female simple, bluntly
pointed; reproductive outlet close to the head; anus immediately above
the tip of the tail. Length of largest females, 3-1/2 in.; breadth,
1/90″; embryos, 1/200″ to 1/125″ in length, by 1/3000″ to 1/2250″ in
breadth; eggs, averaging 1/1000″ by 1/1650″ from pole to pole.

The first discovery of this entozoon, in its embryo state, was made
by Wucherer on the 4th of August, 1866. To use Dr Da Silva Lima’s
words:--“At the moment when Wucherer was seeking for the _Bilharzia
hæmatobia_, he found instead of it an unknown worm. Our illustrious
collaborator,” adds Dr Lima, “has made his important discovery known
under the modest title of ‘Preliminary Notice on a species of Worm at
present not described;’ and still more modestly Wucherer formulated in
the following manner his judicious and prudent conclusions:--It would
be rash on my part to put forth a conjecture on the coexistence of
these worms of the hæmatochyluria, and on the etiological signification
which they might have. I shall therefore abstain until I have been able
to make more ample investigations, and until I have been permitted to
examine the corpse of a hæmaturic, which has not yet been possible.”
(‘Gazeta Medica da Bahia,’ Dec., 1868, p. 99.)

In the year 1868 Dr J. H. Salisbury referred certain ova which he found
in the urine to a new and distinct species of nematode. Although he had
no acquaintance with the adult parasite, Dr Salisbury at once placed
the “species” in the genus Trichina. Here is what he says:--“_Trichina
cystica_ (Salisbury).--This is a small species which I have found in
the human bladder. In all my examinations I have met with this little
entozoon in three cases only. In two of these it was only occasionally
met with in the urine. In the other it occurred in great numbers.
Frequently from ten to fifteen ova were found in a single drop of urine.”

It is important to remark, that there was no hæmaturia in the last-named
case, which Dr Salisbury describes as one of “cystinic rheumatism,”
or “severe cystinæmia associated with rheumatism and paralysis.” The
patient “had been insane for several years. Her urine was passed milky,
with granular cystine, and was dense and scanty.” It is likewise added:
“No examination was made of the muscles after death to determine whether
this species burrowed in the tissue, like the (_Trichina_) _spiralis_.”

So much for the principal facts recorded by Dr Salisbury. His paper is
accompanied by two woodcut figures of the ova (× 300 diam.), and one
representation of the embryo (× 1000 diam.). If these figures give the
size correctly, the ova measure only about 1/800″ in length, by 1/1560″
in breadth, whilst the embryo would be about 1/500″ from head to tail.

On the 17th of May, 1872, I communicated to the Metropolitan Counties
Branch of the British Medical Association a paper on ‘_Bilharzia_,’
and in an Appendix to it I wrote as follows:--“A most interesting
circumstance connected with this case of ‘_Bilharzia_’ from Natal
lies in the fact that I obtained from the patient some other urinary
parasites in the egg-condition (fig. 38). On five separate occasions
I obtained one or more specimens of the eggs or embryos of a minute
nematode. In one instance there were about fifty of these ova in the
urine, their contained embryos being well developed and in a state of
activity. Usually they were all in this advanced condition; but on the
25th of July, 1870, several were observed in much earlier stages of
development. One of these was of a triangular form; its shape, granular
contents, and clearly defined limiting membrane, indicating separation
from the rachis within the ovarian tube. Another early form was
perfectly spherical, with a well marked chorional envelope and double
contour. These forms measured about 1/750″ in diameter. The fully grown
eggs observed at the same time gave a longitudinal measurement of 1/500″
by 1/1000″ in breadth. On adding any stimulus, such as diluted sulphuric
acid, the embryos moved themselves freely within the egg. After allowing
the urine to stand for forty-eight hours, I found, on the 27th of July,
that the shells of the ripe ova had dissolved, leaving the embryos dead,
but still coiled within a fine transparent envelope. In this state
they were easily separated and examined, when they gave a measurement
of 1/300″ in length, by 1/3500″ in breadth. On two occasions, whilst
engaged in rearing the larvæ of _Bilharzia_ in water, I noticed single
specimens of these embryos lying dead; and one of the examples thus
observed gave a length of 1/150″, by 1/3000″ in breadth.”

[Illustration: FIG. 38.--Group of eggs and embryos in a case of endemic
hæmaturia (1870). Original.]

Knowing what errors of interpretation have often crept into
helminthological literature I was more than usually cautious in
pronouncing upon the source of these urinary parasites. Accordingly,
I remarked that “future discoveries might enable us to identify
the species of nematode to which these ova are referable.” I also
added:--“Notwithstanding discrepancies as to size, I am inclined to
think that Dr Salisbury and myself have been made acquainted with
nematode eggs and embryos referable to one and the same species of
parasite. I do not care to speculate as to the origin of these ova.
Long ago I gave in my adhesion to the determinations of Schneider in
respect of the so-called _Spiroptera hominis_, but I am by no means
certain that his position may not be disturbed by fresh discoveries. It
is not a little remarkable that the parents of my patient should have
averred that she passed three small vermiform entozoa by the urethra,
corresponding, to judge from their verbal statements, very closely with
the ordinary appearances of _Filaria piscium_.”

Having written thus much seven years back, it is with natural pleasure
that I find my anticipations already verified. Knowing that I was
dealing with parasites in their earliest larval stages, it never
occurred to me to give a specific name to them, and I could not possibly
approve of Dr Salisbury’s nomenclature, for which there was no good
ground.

In the original discovery Dr O. Wucherer procured the worms from the
chylous urine of a female in the Misericordia Hospital at Bahia; and
on the 9th of the following October, 1866, he obtained similar worms
from another female suffering from hæmaturia. He also afterwards found
them in a man whose urine was slightly chylous, but not hæmatic. In
all cases these sexually-immature nematodes were alive. In September,
1872, Dr A. Corre furnished a careful description of similar worms found
by Dr Crévaux in a hæmato-chylurous patient at Guadeloupe. Dr Crévaux
frequently examined the blood of this patient but found no hæmatozoa.
In like manner in Brazil, Dr J. Silva Lima sought in vain for worms
in the blood of no less than five patients, all of whom suffered from
hæmaturia, and whose urine contained numerous nematoid worms.

Towards the close of the year 1872 the biological world was startled by
the announcement of the discovery of minute Filariæ in human blood. Dr
T. R. Lewis had found microscopic worms in the blood, and also in the
urine, of persons suffering from chyluria. The worms could be obtained
from day to day by simply pricking any portion of the body with a
finely pointed needle. To this hæmatozoon Lewis gave the trinomial term
_Filaria sanguinis hominis_, which thus fitly distinguished it from the
_Filaria papillosa hæmatica canis domestici_ described by Grube and
Delafond. Dr Lewis found the average size of the parasite to be 1/75″ in
length by 1/3500″ in breadth. He observed that while it exists in the
blood the body is enclosed in a delicate transparent tunic or cyst. The
worm was never absent from urine in chyluria. In a case in which there
was a milky discharge from the eyes the worms were also detected. In one
case Lewis calculated that 140,000 Filariæ were present in the blood--a
number certainly not relatively large seeing that MM. Grube and Delafond
estimated the verminiferous blood of their several dogs to contain
numbers varying from 11,000 to 224,000. Lewis also found Filariæ in the
kidneys and supra-renal capsules of a woman who died of chyluria. It did
not appear probable that the worms underwent further development in the
human body. On this point Lewis remarks:--“Not only may those hæmatozoa
found in man live for a period of more than three years, but there is no
evidence that they have any tendency to develop beyond a certain stage
as long as they remain in the circulation.” Dr Lewis judged that the
form of chyluria associated with this condition of the blood was local
and intimately related with a tropical climate. The milky condition
of the urine comes on suddenly, not only at first, but on succeeding
occasions also. It is frequently accompanied by more or less distinctly
marked symptoms of various other obscure diseases, including temporary
swellings in the face or extremities. From certain appearances of
intestinal ulceration Lewis thought that the parasites might gain access
to the system by the alimentary canal, possibly from the tank-water or
the fish inhabiting it. He considered the state of the urine to be due
to the mechanical interruption offered to the flow of the nutritive
fluids of the body. The accidental aggregation of the Hæmatozoa might
give rise to obstruction of the currents within the various channels, or
occasion rupture of their extremely delicate walls, and thus cause the
contents of the lacteals, lymphatics, or capillaries, to escape into the
most conveniently placed excretory channel.

Compressed into a small compass, I think the above is a fair statement
of the leading facts and phenomena discovered by Lewis. The whole
subject of hæmatozoology immediately received additional impulse, the
consequences of which have not yet terminated. In this country Welch was
stimulated to investigate the structure of _Filaria immitis_ in the dog,
whilst others sought diligently for nematoid hæmatozoa abroad.

On the 20th of April, 1874, Dr Prospero Sonsino communicated to the
Neapolitan Royal Academy his memoir entitled “Researches concerning
_Bilharzia hæmatobia_ in relation to the endemic hæmaturia of Egypt,
with a notice concerning a nematoid found in the human blood.” In this
brochure he made known the fact of his having discovered microscopic
Filariæ in a young Egyptian Jew, in the following words:--“On the 1st of
February last, having well washed the finger of the boy, I placed one
drop of blood under the microscope, when with astonishment I discovered
a living organism of the form of a nematode, resembling _Anguillula_,
in the midst of the hæmatic corpuscles. The worms glided amongst the
globules, which were tossed about by their lively movements, showing
various appearances according as they presented themselves either from
the sides, the edges, or the front of the disk” (‘Ricerche,’ &c., pp.
11, 12). Dr Sonsino took every precaution to prevent error, subsequently
verifying his “find” from the same patient. Dr Sonsino directs attention
to two of his own characteristic figures of the worm, and subsequently
states not only that he found examples of the Filariæ in the urine
of this same youth, but also “in the urine of another patient.” The
parasites from these two sources being figured side by side, it was
clear, from their resemblance, that they referred to one and the same
species of entozoon. Dr Sonsino having compared the facts supplied
by these cases, was satisfied that the nematodes in question were
specifically identical with those that I had previously obtained from
my little African patient. However, Dr Sonsino was of opinion that his
Filariæ were not precisely the same as those that had been described by
Lewis.

On the 8th of April, 1876, I received from Dr William Roberts, of
Manchester, some capillary tubes, charged with blood, obtained from a
patient suffering from chyluria. The tubes had been transmitted by Dr
Bancroft, of Brisbane, Queensland, Australia; and in fulfilment of the
donor’s request, Dr Roberts afforded me an opportunity of examining
their contents, he having himself verified Bancroft’s statement
that they contained Filariæ. It was not until May 22nd that I found
opportunity to confirm the observations of Drs Bancroft and Roberts. The
contents of some of the tubes had by this time completely dried up; but
in others, to which diluted glycerine had been added, the blood appeared
tolerably fresh. In what might be reckoned as the sixth part of the
contents of one of the tubes, spread on a glass slide, I detected about
twenty Filariæ, three of which I sketched _in sitû_, in order to compare
them with the figures of Lewis, and also with others that I had procured
from my _Bilharzia_-patient in the year 1870. There could not, I
thought, be any doubt as to the identity of all these sexually-immature
nematoids. One novelty, however, presented itself in the presence of a
solitary and empty egg envelope, measuring about 1/500 of an inch in
its long diameter, and thus corresponding precisely with the ova that I
obtained from the urine in my _Bilharzia_ case.

According to Bancroft, chyluria is somewhat common in Brisbane; and the
case here brought forward was not the only one of the kind which had
already furnished Filariæ in the blood. The patient was a little girl
ten years of age.

Thus stood the facts in the spring of 1876. Having informed Dr
Bancroft that a nematoid egg had been detected in the Australian blood
transmitted to England, he was induced to make further investigations.
These happily resulted in the discovery of the adult worm; the
circumstances attending the “find” being recorded by Dr Bancroft in a
letter written to myself and dated from Brisbane, Queensland, April
20th, 1877. He wrote as follows:--“I have labored very hard to find the
parental form of the parasite, and am glad to tell you that I have now
obtained five specimens of the worm, which are waiting to be forwarded
by a trustworthy messenger.

“I have on record about twenty cases of this parasitic disease, and
believe it will be the solution of chyluria, one form of hæmaturia, one
form of spontaneous lymphatic abscess, a peculiar soft varix of the
groin, a hydrocele containing chylous fluid, together with some forms
of varicocele and orchitis. These I have verified. In the colony there
are no cases that I can find of elephantine leg, scrotal elephantiasis,
or lymph scrotum; but from the description of these diseases in the
volume on skin and other diseases of India by Fox, Farquhar, and Carter,
and from Wm. Roberts’ article on the latter in his volume on urinary
diseases, I am of opinion that the parasitic nature of the same will be
established.

“The worm is about the thickness of a human hair, and is from three to
four inches long. By two loops from the centre of its body it emits the
Filariæ described by Carter in immense numbers.

“My first specimen I got on December 21st, 1876, in a lymphatic
abscess of the arm; this was dead. Four others I obtained alive from
a hydrocele of the spermatic cord, having caught them in the eye of a
peculiar trochar I use for tapping. These I kept alive for a day and
separated them from each other with great difficulty. The worm when
immersed in pure water stretches itself out and lies quite passive. In
this condition it could be easily washed out of hydroceles through a
large-sized trochar from patients known to suffer from Filariæ.”

In July, 1877, I announced Bancroft’s discovery in the ‘Lancet,’ naming
the parasite _Filaria Bancrofti_, and in the following September I sent
the editor an account of the results of my study of the adult worms
received from Brisbane in the interval. These examinations supplied me
with the diagnosis already given (p. 181).

On the 29th of September, 1877, Dr Lewis published a paper in the
‘Lancet,’ wherein, after alluding to my previous announcement respecting
the discovery of _Filaria Bancrofti_, he describes under the name of
_Filaria sanguinis hominis_ a mature worm, which was evidently the
same parasite. Not unnaturally Dr Lewis put aside the nomenclature I
had employed, on the ground that the name originally given by himself
to the embryonal form ought to be retained, and that “a new name, if
not necessary on anatomical grounds, would only lead to confusion.”
Personally I have no objection to Lewis’s specific name, but if the
question of priority is to determine the nomenclature, then I fear we
ought to call the species _Filaria Salisburyii_. Obviously the retention
of Dr Salisbury’s nomenclature (_Trichina cystica_) would be unsuitable
and misleading.

[Illustration: FIG. 39.--_Filaria Bancrofti._ _a_, Female (nat. size);
_b_, head and neck (× 55 diam.); _c_, tail; _d_, free embryo (× 400
diam.); _e_, egg containing an embryo; _f_, egg, with mulberry cleavage
of the yolk (× 360 diam.). Original.]

When (prior to Lewis’s discovery of the hæmatozoa) I had myself
encountered larval nematodes of the same character as those described by
Salisbury, I, like Wucherer, was careful not to employ a special name
for an immature form, which might or might not represent a worm hitherto
known to science. The paper in which I described the adult worm from
specimens supplied by Bancroft appeared in the ‘Lancet,’ Oct. 6th,
1877, the facts being stated as follows:--

On the 28th of August, 1877, I received a small collection of entozoa.
The box contained the promised Filariæ, and also eight bottles filled
with various intestinal worms taken from animals. The Filariæ were
enclosed in four small tubes and preserved in glycerine. Three of the
tubes (marked 1, 2, 3) contained sexually-mature worms, the fourth being
labelled “Sediment from adult _Fil. sang._--young and ova.” I described
their contents in succession. Thus, on the 6th of September, 1877, I
examined the Filaria in tube No. 3. The specimen was injured and in four
portions, these collectively measuring three inches in length. Although,
to the naked eye, the worm had appeared to Dr Bancroft to be of the
thickness of an ordinary human hair, yet I found it about 1/90″ at the
thickest part. It was a female. At the same time I examined the specimen
in tube No. 1. This was also a female. Towards the centre of the body a
hernial protrusion of the uterine horns and intestine had taken place.
In a lithograph sent by Dr Bancroft this specimen was figured and
described as the “parent worm of the _Filaria sanguinis_, emitting young
Filaria from two loops.” Later on I examined the contents of tube No. 2.
In it I found one tolerably perfect female Filaria, and also a delicate
shred forming part of one of the uterine horns of another worm. This
filament measured one inch and a half in length, and was coiled round
the complete worm. On transferring it to a watch-glass containing water,
hundreds of embryos made their escape. Owing to the transparency of the
tissues I had much difficulty in finding the reproductive outlet, and
the effort to find it was all the greater because Bancroft’s figure had
misled me. At length I found the vagina and its orifice close to the
head (about 1/20″ from it), the anal orifice being placed within the
1/90″ from the extremity of the tail. The vaginal pouch, 1/100″ long,
was crowded with embryos, and a constriction marked its junction with
the uterus proper, which appeared to divide lower down at a distance of
1/10″ from the head. Towards the tail a fold of the tuba Fallopii was
seen to extend to within 1/20″ of the extremity. All sections of the
uterine system were crowded with germs, eggs, and embryos in their usual
relative situations.

My examinations of the ova and embryos were chiefly made from the
“sediment” sent in a special glass tube. The fully formed embryos were
1/125″ in length by 1/2500″ in breadth. They each showed a double
skin, the outer envelope in the more advanced specimens leaving clear
spaces at either end of the body, resulting from commencing ecdysis.
I saw no trace of intestinal tube, but a central line of condensation
marked an early differentiation of the somatic granular contents. The
less advanced embryos were mostly enclosed in a chorional envelope, the
smallest free embryos measuring only 1/200″ in length by 1/3000″ in
breadth. These had no double contour. The ova, whose yolk-contents were
still in various stages of cleavage, gave an average long diameter of
1/900 to 1/1000 of an inch.

Such are the facts I made out, and they enabled me to amend the
characters of the species.

As regards nomenclature, I associated Dr Bancroft’s name with the
sexually-mature worm as being in harmony with the binomial method and
little calculated to mislead; moreover, it helped to fix both the source
and date of the discovery (Brisbane, Dec. 21st, 1876). The use of this
nomenclature detracts nothing from the high merits of Lewis, who first
named the immature worm _Filaria sanguinis hominis_. As it now turns
out, both Dr Salisbury and myself had previously been made acquainted
with the young of _Filaria Bancrofti_; but it was reserved for Lewis
to discover the hæmatozoal character of the embryos of this worm, and
actually to take them from the blood. It was a singular circumstance,
that when I was engaged in treating my little African patient for
trematode hæmatozoa, it never once occurred to me that the numerous
nematoid embryos mixed with the Bilharzia ova were hæmatozoal. As before
remarked, it was alleged that my patient had passed worms two or three
inches long by the urethra. I therefore concluded that these were the
parents of the eggs and embryos, and that all of them were urinary.
The inference was wrong, but it has instructively shown how near one
may go towards a great discovery without really making it. As regards
the larvæ, notwithstanding some slight differences in regard to size
and so forth, I have little hesitation in saying that all the embryo
forms severally described by Salisbury, by myself, by Lewis, Sonsino,
Wucherer, Crévaux and Corre, Silva Lima, Bancroft, Manson, and others,
are referable to one and the same species.

Into the clinical bearings of this subject it is impossible for me to
enter at any length, but I may remark that these parasites appear to
be associated with, if not actually the cause of, several distinct
morbid conditions. To one of these Bancroft has given a separate name
(_Helminthoma elastica_). This is a highly elastic form of growth to
which I have already alluded under the title of “lymphatic abscess of
the arm.” In the first valuable report on Hæmatozoa, by Dr Patrick
Manson, of Amoy, China, this careful observer gives interesting
particulars of no less than fifteen cases in which hæmatozoa were found.
Two of these patients had _Elephantiasis scroti_, two had lymph-scrotum,
two were lepers (one having scrotal disease), two had enlarged inguinal
glands, one had anasarca; and of the remaining six, spoken of as having
no concomitant disease, one had enlarged glands and abscesses, and
another suffered from marked debility. It would thus appear that what is
ordinarily termed “good health” is rarely associated with a hæmatozoal
condition of the blood in the human subject. The cases given by Lewis
and Manson, where absolutely no recognisable disease existed, must
be regarded as exceptional. Disease, moreover, may exist without any
palpable symptoms being exhibited by the “bearer,” and thus perhaps it
was with the hæmatozoal dogs of Gruby and Delafond to which I shall
again have occasion to allude. Even those animals that carried upwards
of two hundred thousand microscopic Filariæ in their blood appeared to
suffer no inconvenience whatever.

In the autumn of 1877 Dr Da Silva Lima published an article in the
‘Gazeta Medica da Bahia,’ in which he dwelt upon the labors and merits
of Wucherer, and, judging from an omission in one of my memoirs, he
supposed that I had insufficiently acknowledged Wucherer’s claims.
A translation of this article appeared in the ‘Archives de Médicine
Navale,’ with an important appendix by Dr le Roy de Méricourt. In this
_addendum_ the French _savant_ showed that the omission on my part was
unintentional, and had been corrected by me in a later memoir. Not
only had I been amongst the earliest in England to enforce Wucherer’s
claims in respect of the micro-Filariæ, but I had first announced
his discoveries in connection with _Anchylostoma duodenale_. In my
translation of Wucherer’s memoir (‘Ueber die Anchylostomum Krankheit’) I
spoke of the melancholy satisfaction I had in knowing that the memoir in
question was “among the last that appeared from the pen of that gifted
and amiable physician.” Some notice of Dr Lima’s paper and its appendix
by Dr A. le Roy de Méricourt appeared in the ‘Lancet’ for Jan. 5th,
1878, and I also published a full translation of it, with explanatory
notes, in the ‘Veterinarian’ for Feb., 1878. Later on, in the ‘Lancet’
(March 23rd, 1878), Dr Da Silva Lima published an interesting letter
correcting a misconception that had incidentally arisen in the mind of
a commentator (on the Helminthological work of 1877), and at the same
time he pointed to the original facts connected with the discovery
of Wucherer’s Filaria. As my views are in perfect accord with those
of Dr Da Silva Lima, I can only regret that errors of interpretation
should have crept into the discussion. Dr Lima honorably recognises the
nomenclature (_Filaria Bancrofti_) which I proposed for the adult worm,
and only claims for Wucherer that which is fairly due.

On the 4th of January, 1878, I received from Dr Patrick Manson a
manuscript in which he announced the discovery of the larvæ of _Filaria
sanguinis hominis_ in the stomach of mosquitoes. Already, in April,
1877, Dr Bancroft had informed me of his expectation of finding that
these insects sucked up the larvæ of the Filaria whilst engaged in their
attacks on man. Dr Bancroft’s supposition was a very natural one, but
it remained for Manson to make the actual discovery of the existence of
human hæmatozoa, or parasites that had been such, within the stomach of
_Culex mosquito_. I lost no time in making the principal facts public
(‘Lancet,’ Jan. 12th, 1878). Dr Manson at the same time forwarded for
publication a record of thirty-five additional cases of hæmatozoa
occurring in Chinese subjects, together with additional particulars
of one of the cases already published in the ‘Customs Gazette.’ These
were afterwards published as separate contributions in the ‘Medical
Times and Gazette.’ Dr Manson likewise forwarded materials for a paper
entitled “Further Observations on _Filaria sanguinis hominis_.” In this
communication he gave an analysis of the cases (sixty-two in all) in
which he had observed the hæmatozoa, and he added valuable statistical
evidence as to the prevalence of Filariæ in the Amoy district, dwelling
especially on the influence of age, sex, and occupation in determining
the presence of the parasite. He also described the morbid states with
which these entozoa were commonly associated.

On the 7th of March, 1878, I formally communicated to the Linnean
Society a detailed account of Manson’s investigations relating to the
metamorphoses undergone by the Filariæ within the body of the mosquito.
In this paper Manson pointed out that the female mosquito, after
gorging itself with human blood, repairs to stagnant water for the
purpose of digesting the blood, and also for the purpose of depositing
its eggs. During this period, which lasts four or five days, the Filariæ
undergo remarkable changes. Subsequently, in a more perfect state, they
escape into the water, and in this advanced stage they are conveyed to
the human body along with the water as drink. Dr Manson persuaded a
Chinese, whose blood was previously ascertained to abound with Filariæ,
to sleep in a “mosquito house.” In the morning the gorged insects
were captured and examined under the microscope. A drop of blood from
the mosquito was found to contain 120 Filariæ, but a drop taken from
the man’s hand yielded only some thirty specimens. Further stages of
development are accomplished within the human host, ending in the sexual
maturity of the parasite. After fecundation successive swarms of embryos
are discharged by the female worm, a part of whose progeny eventually
gains access to the blood.

Before I proceed to summarise the whole body of facts I must in the next
place state that Manson and myself contributed a joint communication to
the Medical Society of London on the 25th of March, 1878. In this memoir
I especially dealt with the question of priority in connection with the
discovery of the adult worm. I then restated that the adult parasite
was discovered by Dr Bancroft on December 21st, 1876. The discovery
was verified by Dr Lewis on August 7th, 1877, by Dr Silva Araujo
October 16th, 1877, and by Dr F. dos Santos November 12th, 1877. I gave
these dates unhesitatingly, without, however, in any way prejudicing
the question already raised in respect of the identity of the worms
found in each case. My own mind was fully made up on that point, and
affirmatively so. Dr dos Santos’ find was made in conjunction with Dr J.
de Moura in a case of lymphatic abscess of the arm. Clinically viewed,
the case published by Dr Araujo must be regarded as unique. Not only
were adult and embryonic Filariæ found in the same patient, but, what
was far more surprising and interesting, the patient displayed in his
own person several of the disorders hitherto found apart; and he was
more than once attacked by one or two of the diseases. He experienced
a first attack of chyluria three years ago, then attacks of craw-craw
commencing a year ago, the latter being attributed to bathing in a
particular lagoon. He had a second attack of chyluria six months back,
at which time lymph-scrotum appeared, and also scrotal elephantiasis.
Dr Bourel-Roncière pronounced this case to be unique, and attributed
nearly all the disorders to the presence of Wucherer’s embryonic
Filariæ. In a very elaborate analysis of and commentary on Dr da Silva
Lima’s second memoir, Dr Bourel-Roncière warmly claims for Wucherer the
supreme honor in all these discoveries. A number of affections hitherto
regarded as distinct, and all of which appear to be due to the action of
Filariæ, are regarded by Dr Bourel-Roncière as mere phases of one and
the same disorder. This affection he terms _Wucherer’s helminthiasis_.
Dr Manson had indeed arrived independently at a similar conclusion, and
I am confident that Wucherer, were he alive, would in this particular
aspect of the question be the last to claim priority either to Lewis, to
Bancroft, or to Manson.

In this place I may observe that Dr Pedro S. de Magalhães, of Rio de
Janeiro, detected free microscopic nematodes in the potable waters of
Rio (agua da Carioca), which from their similarity he supposes may have
some genetic relation with _Filaria Bancrofti_. In this opinion I cannot
share.

As regards the metamorphoses of the embryo, Manson states that for a
little while after gaining access to the stomach of the mosquito the
embryo undergoes no change (Fig. 40, _a_). In a very few hours changes
commence, resulting in wider separation of the outer skin and an
appearance of transverse markings on the body within (_b_). In the next
stage oral movements occur; the striation becomes more marked, and the
outer envelope is cast off (_c_). Then the striated lines disappear and
a dotted appearance is substituted (_d_). From this condition the embryo
passes to what Manson calls the chrysalis stage, in which nearly all
movement is suspended and the large spots gradually disappear (_e_, _f_,
_g_, _h_, _i_, _j_, _k_). The tail continues to be flexed and extended
at intervals and the oral motions cease. By the close of the third day
the embryo becomes much shorter and broader; but the finely pointed
tail retains its original dimensions, projecting abruptly from the
sausage-shaped body (_m_, _n_). Large cells next appear in the interior
of the body, and by a little pressure one may detect indications of
a mouth (_o_, _p_, _q_, _r_). At this period the embryo begins to
elongate, and at the same time to diminish in width; but the growth
takes place chiefly at the oral end of the body. The mouth becomes
four-lipped, open, and funnel-shaped, and from it a delicate line can
be distinctly traced passing to an opening near the caudal extremity,
the tail itself gradually disappearing (_s_, _t_). Speaking of the most
advanced stage Manson says:--“A vessel of some sort is seen in the
centre running nearly the whole length of the body and opening close to
one extremity. This end is slightly tapered down and is crowned with
three or perhaps four papillæ, but whether this is the head or tail,
and whether the vessel opening near it is the alimentary canal or the
vagina, I cannot say.” Now it is quite evident, I think, from Manson’s
figures that he has here faithfully represented the head and tail,
the former (_u_) to the left, the latter (_v_) to the right. In his
_manuscript_ (from which I am now quoting) there is no special reference
to these two figures; but it is easy to see that these terminal sections
of the body of the advanced embryo closely correspond with the head
and tail of the adult worm (_Filaria Bancrofti_). The curved line
passing to the left (_u_) evidently indicates the commencement of the
partially-formed vagina.

[Illustration: FIG. 40.--Larval Filariæ in various stage of growth from
the mosquito; _a_ to _d_, representing the first stage of metamorphosis
during the first 36 hours, _e_ to _o_, the changes occurring during the
second stage, to the close of the third day; _p_ to _t_, forms seen
during the third stage of metamorphosis from the fourth day onwards. The
figs. _u_, _v_, represent the head and tail only, whilst _t_ shows the
young Filaria in an advanced stage, and drawn to a much smaller scale,
than the others which are here magnified about 125 diameters. Much
reduced from Manson’s original figures.]

How completely Manson took the initiative in this part of the work is
evident even from Lewis’s own later observations. In a paper published
in March, 1878, Dr Lewis, writing from Calcutta and speaking of the
rôle of the mosquitoes, says:--“I had repeatedly examined, in a cursory
fashion, these and other suctorial insects, but had not observed
any parasites suggestive of these embryo-hæmatozoa, hence, when, on
receipt of a communication from Dr Manson a couple of months ago, a
renewed search was made, I was surprised to find that four out of eight
mosquitoes, captured at random in one of the servants’ houses, harboured
specimens of hæmatozoa to all appearances identical with those found in
man in this country. After this, however, several days elapsed before
any mosquitoes could be obtained which contained these embryo-nematoids,
and the specimens obtained on the next occasion were devoid of the
enveloping sheath, which appears to characterise the kind found in
man out here, and apparently, according to Dr Manson, in China also.”
Further on Lewis also remarks, “When the insect is caught shortly
after feeding and the contents of its stomach examined microscopically,
the hæmatozoa, if present, will be observed to manifest very active
movements, which may possibly continue for several hours on the slide.
If the insect be kept for twenty-four hours before examination it is
probable that the movements of the parasites will be more sluggish,
and their form probably altered owing to irregular contractions and
dilatations of their substance--changes which may also occasionally be
observed when embryo-hæmatozoa are preserved on a glass slide, and they
may sometimes be kept alive thus, if in suitable media, for two or three
days. When the insect is not examined till the third day, the contained
parasites will probably manifest marked signs of disintegration--and
possibly every indication of life will have disappeared from many
of the specimens. After the third or fourth day I have not seen any
active specimens of these entozoa in the stomach or in any part of the
alimentary canal of the mosquito; those which remain have undergone
more or less fatty degeneration, and are readily stained with eosin,
which, as far as my experience goes, is not the case so long as they are
alive and active. After the fourth or fifth day it is very rare that
traces of any hæmatozoa-like objects can be detected at all, so that
it must be inferred either that they have succumbed to the digestive
action of the insect’s stomach or been disposed of along with the
excreta.” An important _addendum_ by Lewis records a fortunate incident
as follows:--“It was observed that nearly all the mosquitoes captured
in one of the servants’ houses contained hæmatozoa, so that the supply
of suitable insects in all the stages of their growth became amply
sufficient for all requirements. The result of the examinations under
these favorable conditions has shown that although the stomach digests a
great number of the ingested hæmatozoa, as mentioned above, nevertheless
others actually perforate the walls of the insect’s stomach, pass out,
and then undergo developmental stages in its thoracic and abdominal
tissues.”

I may here observe that Sonsino has instituted a comparison between the
embryos of this Filaria and those of Anchylostoma, by which it appears
that the former measure 0·218 to 0·330 mm. in length, and those of
Anchylostoma 0·430 mm. The hæmatozoa are about forty times longer than
broad, and the larval anchylostomes only fourteen times longer. The tail
of _Filaria_ is conspicuously longer.

In the ‘Lancet’ for June 22nd, 1878, an announcement appeared from the
pen of Mr D. H. Gabb, of Hastings, stating that a patient under his care
formed the habitat of _Filaria sanguinis hominis_; and in the autumn of
the same year a paper which I read to the Linnean Society in the spring
was published. In that paper the following summary was offered:

1. _Filaria Bancrofti_ is the sexually-mature state of certain
microscopic worms hitherto obtained either directly or indirectly from
human blood.

2. The minute hæmatozoa in question--hitherto described as Wucherer’s
Filariæ, _Filaria sanguinis hominis_, _Trichina cystica_, _Filariose
dermathemaca_, and so forth--are frequently associated with the presence
of certain more or less well-marked diseases of warm climates.

3. The diseases referred to include chyluria, intertropical endemic
hæmaturia, varix, elephantiasis, lymph scrotum, and lymphoid affections
generally, a growth called _helminthoma elastica_, a cutaneous disorder
called craw-craw, and also leprosy.

4. It is extremely probable that a large proportion, or at least
that certain varieties of these affections are due to morbid changes
exclusively resulting from the presence of _Filaria Bancrofti_ or its
progeny within the human body.

5. It is certain that the microscopic hæmatozoa may be readily
transferred to the stomach of blood-sucking insects, and it has been
further demonstrated that the digestive organs of the mosquito form
a suitable territory for the further growth and metamorphosis of the
larval Filariæ.

6. The character of the changes undergone by the microscopic Filariæ,
and the ultimate form assumed by the larvæ whilst still within the body
of the intermediate host (_Culex mosquito_), are amply sufficient to
establish the genetic relationship as between the embryonal _Filaria
sanguinis hominis_, the stomachal Filariæ of the mosquito, and the
sexually-mature _Filaria Bancrofti_.

In the month of September, 1878, I received a letter from Dr da Silva
Lima announcing the fact that Dr Araujo had verified the existence
of the embryos of _Filaria Bancrofti_ in mosquitoes, at Bahia. These
mosquitoes had, I understood, attacked a French priest in whose blood
Dr Araujo also detected Filariæ. Thus, it fell to the lot of Araujo,
through his untiring zeal, to verify in Brazil all the separate
discoveries of Bancroft, Manson, and Lewis.

In the October issue of the ‘Pathological Society’s Transactions’ for
1878 Dr Bancroft records numerous cases of filarious disease, and
he gives a succinct account of the circumstances connected with his
original discovery.

In a clinical lecture published October 12th, 1878, Dr Tilbury Fox
seeks to diminish the value of these discoveries, characterising
helminthological investigators as merely “recent writers.” Dr Fox
denies that Filariæ are a cause of true elephantiasis, but admits
the occurrence of “elephantoid inflammation and inflammations due
to Filariæ.” Dr Fox’s statement that “Filariæ have not been found
in uncomplicated elephantiasis, that is, in disease without chylous
exudation,” seems to me to be directly at variance with Manson’s
recorded experiences. I hold that Manson has confirmed the truth of
Lewis’s views, and that he has thoroughly proved that (to use his
own words) “varicose groin glands, lymph scrotum, elephantiasis, and
chyluria are pathologically the same disease.” In the first instance I
was myself led to conclude that some of the forms of elephantiasis might
be due to other causes than obstruction of the lymphatics caused by the
presence of Filariæ; but the explanations of Lewis, of Bancroft, and of
Manson more especially, have almost entirely removed this doubt. Those
who seek to explain away the connection between genuine elephantiasis
and Filariæ will do well to study Manson’s last important memoir. He
shows that “elephantiasis and allied diseases are much more frequently
associated with the parasite than are other morbid conditions.” This
fact is brought out very clearly in his table of 670 cases, from which
it appears that 58 per cent. of cases of Filaria are associated with
elephantoid disease.

When this opposition to Manson’s views is likely to cease (on the part
of those who do not happen to have been in any way instrumental to the
discoveries in question) it is not easy to say. In a brief communication
which appeared in the last number of the ‘Medical Times and Gazette’
for 1878, Dr Manson successfully combats the doubts that have been
entertained respecting the rôle of the mosquito. Because Lewis found
that canine hæmatozoa were digested, and thus perished in the stomach of
mosquitoes, it had been argued that _human_ hæmatozoa must necessarily
undergo similar processes, and consequently die. Those who oppose the
views of helminthologists in respect of the intermediary host-function
of insects on such grounds can have very little general, and still less
special knowledge of the phenomena of parasitism. It is the old story.
When any new discovery is made, it must always pass through the ordeals
of denial and doubt before it can be generally accepted as true; and,
as in the case of Jenner’s immortal discovery, there will always remain
a certain number of peculiar people who show themselves hostile to every
advance in science. Dr Manson may take comfort from this consideration,
and rest assured that the value of his discovery is quite unaffected by
the opposition referred to.

Since I communicated the results obtained by Manson, Lewis, myself,
and others to the Linnean Society, an even more exhaustive summary
of the facts has been published by Dr Bourel-Roncière, in the
‘Archives de Médecine Navale.’ The distinguished author does full
justice to the writings of English helminthologists, and dwells, with
emphasis, upon the finds and interpretations of Lewis, Manson, and
Bancroft. Incidentally, also, he comments upon Sir Joseph Fayrer’s
early recognition of the etiological identity of hæmato-chyluria
and elephantiasis, on other than helminthic grounds. The frequent
concurrence of the two affections had especially struck Sir J. Fayrer
as pointing to a probable common origin. He had also surmised that the
disorders might be due to parasites.

Dr Bourel-Roncière, alike with the caution, precision, and logical
reasoning of a cultured _savant_, concludes his elaborate review in the
following terms:--“There are the facts. Certainly, many points remain
obscure, many problems await a solution, and the last word has not been
said on the actual part which the parasite plays in the pathogenesis
of the affections above enumerated--its mode of action, the importance
of its rôle, the extent of its pathological domain, the habitat of its
progenitors, their identity, and so forth. All these questions will
only be elucidated by necroscopic researches, which at present remain
absolutely wanting.”

“However, notwithstanding the doubts which hover over the future
value of these curious discoveries, it is difficult not to recognise
their importance in the study of certain tropical diseases--which up
to the present time have been attributed to vague and undetermined
causes--hæmato-chyluria and elephantoid affections principally.
Apart from the interest which attaches to the natural history of
the nematoids, they raise, in effect, etiological and prophylactic
questions, the extreme importance of which we believe it would be
needless to demonstrate. It is greatly to be desired that the researches
should be taken up in other parts of the globe, where endemicity
and perhaps greater facilities for necroscopic investigation would
render them fruitful--Cochin-China, Tahiti, &c. Fresh observations are
necessary to confirm the first and to fill up notable gaps. The way has
been brilliantly opened by the English and Brazilian physicians. Let our
colleagues in the French colonies put their shoulders to the wheel; they
have before them a vast field of study to explore.”

Since the above remarks were written I have received several
communications from Dr Bancroft, and also others from Drs da Silva Lima,
Araujo, Assis Sousa, Paterson, Hall, of Bahia--the two last named being
English physicians in practice there. I regret that I can do little more
than refer to the writings of these authors in the Bibliography below;
but I may observe that Drs Paterson and Hall have ascertained that the
proportion of the population of Bahia affected by Filaria is 8-1/2 per
cent. Out of 309 persons examined, 26 had hæmatozoa, which is, roughly,
one in twelve, or more strictly, 8·666 per cent.

Amongst recent memoirs that by Sir J. Fayrer, read to the
Epidemiological Society on the 5th of February, 1879, deserves especial
attention. In regard to its significance, I have only space to remark
that, much as we may regret the little interest shown by our hospital
physicians and surgeons in this subject, it is particularly gratifying
to see experienced Indian officers like Sir J. Fayrer, Mr Macnamara, and
Dr John Murray, coming forward both to aid and render homage to their
junior colleagues in Eastern parts, who are successfully labouring to
advance the cause of helminthology and scientific medicine.

In concluding this subject I may observe, that one of the greatest
hindrances to the due recognition of the remarkable part played by
parasites in the production of human endemics and animal epizoötics
arises from the circumstance that no inconsiderable number of minute
worms may infest a host without obvious injury. This immunity proves
nothing. If, for example, we take the case of _Trichina_ we find that
several millions of entozoa may exist in the human, or, at all events,
in the animal bearer, without producing any symptom of discomfort. In
such cases it is not possible to determine the strict limits of health
and disease; nevertheless, were we to double the amount of infection,
the imaginary line of demarcation is at once bridged over and the
parasites become acknowledged as directly responsible for grave symptoms
which may even prove fatal to the bearer. Again, the relative strength
and size of the infected host constitute factors that materially
limit the power of the parasite for injury. Where the entozoa are of
minute size, and where their injurious action is primarily due to the
mechanical obstructions they set up, it is clear that the virulence of
the helminthiases, or resulting diseased conditions, will mainly depend
upon the number of intruders.

Another consideration of the highest value in relation to epidemiology
generally, and more especially in regard to the practical question as to
the best methods of stamping out parasitic plagues, is that which refers
to the life-history of the entozoon itself. It must be obvious that in
all cases where the intermediate host can be captured and destroyed,
the life-cycle of the parasite can be broken and interrupted, and if
thus broken, there is an end to the further propagation of the species.
The knowledge that we have acquired by experimental research in this
connection has already enabled us to set a limit upon the prevalence of
certain well-known disorders, such as Trichinosis, Cestode-tuberculosis,
and so forth. In the case of epizoötics, however, which are indirectly
due to the action of intermediary hosts that cannot be readily captured
or destroyed, then our power of arresting the disease is comparatively
limited. In the present case it is probably not necessary either that
a dead or living mosquito should be swallowed to insure infection; but
it _is_ necessary that the parasitic larvæ should have dwelt within the
mosquito in order to arrive at the highest stage of larval growth prior
to their re-entrance within the human territory. Undoubtedly, the larvæ
are swallowed with potable waters. Perfect filtration before use would
certainly check, if in course of time it did not totally extinguish
several of the many virulent diseases that now afflict the inhabitants
of warm climates.

It is with reluctance that I terminate this article, but in the closing
pages of this work (Book II, Section V) I hope to add a few more
particulars in reference to Lewis’s latest researches.

BIBLIOGRAPHY (No. 23).--_Araujo, A. J. P. da Silva_, “Memoria sobre a
Filariose,” &c., Bahia, 1875; see also ‘Arch. de Méd. Nav.,’ 1875 and
1878.--_Bancroft, J._, “Cases of Filarious Disease,” in ‘Pathological
Soc. Trans.’ for 1878, vol. xxix, p. 407.--_Bourel-Roncière_, “_Résumé_
of and Commentary upon the writings of Silva Lima, Silva Araujo, and
others,” in ‘Arch. de Méd. Nav.’ for March, 1878.--_Idem_, “Pathologie
exotique. De l’hématozoaire nématoïde de l’homme et de son importance
pathogénique, d’après les travaux Anglais et Bréziliens des dernières
années;” _ibid._, for August and Sept., p. 113-134 and p. 192-214,
1878.--_Cobbold, T. S._, “Discovery of the Adult Representative of
Microscopic Filariæ,” ‘Lancet,’ July, 1877, p. 70.--_Idem_, ‘On _Filaria
Bancrofti_,’ _ibid._ Oct., 1877, p. 495.--_Idem_, “Verification of
Hæmatozoal Discoveries in Australia and Egypt,” ‘Brit. Med. Journ.,’
June, 1876.--_Idem_, “Obs. on Hæmatozoa,” ‘Veterinarian,’ October,
1873.--_Idem_, “Remarks on the Ova of another Urinary Parasite (in the
paper on ‘Bilharzia’) from Natal,” ‘Brit. Med. Journ.,’ July 27th,
1872, p. 89; see also Bibl. No. 12.--_Idem_, “Entozoa in Relation to
the Public Health” (various papers), ‘Med. Times and Gaz.,’ Jan. and
Feb., 1871.--_Idem_, ‘Worms’ (l. c., p. 151), 1872.--_Idem_, “Hæmatozoa;
Fresh Discoveries by Lewis,” ‘Lancet’ for Feb. 6, 1875.--_Idem_ (brief
notice), the ‘Veterinarian,’ p. 209, March, 1875.--_Idem_, “On the
Discovery of the Intermediary Host of _Filaria sanguinis hominis_,”
‘Lancet,’ Jan. 12, 1878, p. 69.--_Idem_, “On the question of Priority
of Discovery,” Rep. of Med. Soc. of Lond., in ‘Lancet,’ March 30, 1878,
p. 465.--_Idem_, ‘Mosquitoes and Filariæ’ (explanatory note), in ‘Brit.
Med. Journ.,’ March 16, 1878, p. 366.--_Idem_, “On the Life-history
of _Filaria Bancrofti_, as explained by the discoveries of Wucherer,
Lewis, Bancroft, Manson, Sonsino, myself, and others,” “Report of the
Proceed. of the Linnean Soc.” for March 7, 1878, in ‘Pop. Science Rev.,’
April, 1878; and afterwards published _in extenso_ in ‘Journal Linn.
Soc.,’ Oct. 31, 1878.--_Idem_, “On _Filaria Bancrofti_,” in Part iv of a
series of papers on the Parasites of Man, in the ‘Midland Naturalist,’
August, 1878.--_Idem_, “On _Filaria sanguinis hominis_,” in a letter
to the ‘Lancet,’ July 13, 1878, p. 64.--_Idem_, “Filariæ and Leprosy”
(case from Bancroft); ‘Lancet,’ Feb. 1, 1879.--_Corré, A._, “Note sur
l’helminthe rencontré dans les urines hémato-chyleuses,” ‘Rev. des
Sci. Nat.,’ 1872.--_Cossé_, “Sur l’helminthe rencontré par Wucherer
et Crevaux,” &c., ‘Rev. Montpellier,’ tom. i, p. 190.--_Couto, A._,
“These de concourso,” Bahia, 1872.--_Crevaux, J._, “De l’hématurie
chyleuse, &c.,” 1872; also in ‘L’Union Médicale,’ 1872 (abs. in ‘Brit.
Med. Journ.,’ July, 1872, p. 100); also in ‘Arch. de Méd. Nav.,’ 1874;
and in ‘Journ. de l’Anat. et de la Physiol.,’ 1875 (see also Silva
Lima).--_Davaine, C._, ‘Traité,’ 2nd edit., p. 944; ‘Hæmatozoaires,’
supp., 1877.--_Fayrer, Sir J._, “Filaria sang. hom.,” ‘Lancet,’ March
16, 1878, p. 376.--_Idem_, “Elephantiasis Arabum,” ‘Med. Times and
Gaz.,’ Dec. 1, 1877, p. 588; “On the Relation of _Filaria sanguinis
hominis_ to the Endemic Diseases of India,” in the ‘Lancet,’ Feb. 8
and 15, and reprinted from the ‘Med. Times and Gazette’ (same date),
1879.--_Gabb, D. H._, letter in ‘Lancet,’ June 22, 1878.--_Leuckart_,
l. c., s. 638, 1876.--_Lewis, T. K._, “On a Hæmatozoon in Human Blood,”
‘San. Comm. 8th Rep.,’ Calcutta, 1872; ‘Med. Press,’ 1873, p. 234;
‘Indian Ann. Med. Sci.,’ 1874; ‘Lond. Med. Rec.’ (abs. by myself in
vol. i, p. 5), 1873.--_Idem_, “Pathological Significance of Nematode
Hæmatozoa,” ‘Tenth Ann. Rep.,’ 1873, Calcutta (reprint), 1874; ‘Ind.
Ann.,’ 1875.--_Idem_, “Remarks regarding the Hæmatozoa found in the
Stomach of _Culex mosquito_,” ‘Proc. Asiatic Soc. of Bengal,’ March,
1878, p. 89.--_Idem_, “Flagellated Organisms in the Blood of Rats”
(being portion of a paper on “The Microscopic Organisms found in the
Blood of Man and Animals,” in ‘14th Annual Report of the San. Comm.
with the Govt. of India’), in the ‘Quart. Journ. of Micr. Science,’
Jan., 1879.--_Idem_ (published since the present article was written),
“The Nematoid Hæmatozoa of Man,” _ibid._, April, 1879.--_Lima, J.
F. da Silva_ (with _Crevaux_), ‘Memoria sobre hematuria chylosa
ou gordurosa des paizes quentes;’ extrahida da ‘Gazeta Medica da
Bahia,’ 1876; repr. in ‘Arch. de Méd. Nav.,’ Dec., 1878 (see also Le
Roy de Méricourt).--_Magalhães, Pedro S. de_, “Filarias em estado
Embryonario, encontradas n’agua tida como potavel (agua da Carioca),”
‘O Progresso Medico,’ Dezembro, 1877, p. 57.--_Idem_, “Nota sobre
os nematoides encontrados no sedimento deposito pela agua (potavel)
da Carioca,” ‘O Prog. Med.,’ 1 de Setemb., 1878, p. 577.--_Idem_,
“Caso de filariose de Wucherer;” _ibid._, 15 de Setemb., 1878, p.
589.--_Makina, M.D._, “Filaria in Chyluria,” letter in ‘Lancet,’
Feb. 22, 1879, p. 286.--_Manson, P._, “Rep. on Hæmatozoa,” ‘Customs
Gazette,’ No. 33, Jan.-March, 1877; see also ‘Med. Times and Gaz.’
for Nov. 10, p. 513, Nov. 17, p. 538, and Nov. 24, p. 563; Dec. 1,
p. 589, 1877; also Jan., 1878.--_Idem_, “Additional Cases;” _ibid._,
March 2, 9, 23, 1878.--_Idem_, “On _Filaria sanguinis hominis_, and
on the Mosquito considered as a Nurse,” ‘Proc. Linn. Soc.,’ March 7,
1878; see also report in ‘Nature,’ March 28, 1878, p. 439.--_Idem_,
“On _Filaria sanguinis hominis_, clinically considered in reference to
Elephantiasis, Chyluria, and allied Diseases,” ‘Rep. of Med. Soc. of
Lond.,’ in ‘Lancet,’ March 30, 1878.--_Idem_, “Further Observations on
_Filaria sanguinis hominis_,” “Med. Rep.” for April-Sept., 1877, in
‘Customs Gazette,’ Shanghae, 1878.--_Idem_, “The Development of the
_Filaria sanguinis hominis_,” ‘Med. Times and Gaz.’ for Dec. 28, 1878,
p. 731.--_Méricourt, A. Le Roy de_, in Appendix to an art. entitled
“Nouvelle phase de la question relative à la nature parasitaire de
la chylurie. Découverte du représentant adulte de la ‘Filaire de
Wucherer,’” par le Dr da Silva Lima, from the ‘Gaz. Med. da Bahia,’
Sept., 1877; see also the ‘Lancet,’ Jan., 1878, p. 22 (editorial
notice).--_Moura, J. de_, ‘These de Concourso,’ 1877.--_O’Neill_, “On
Craw-craw,” ‘Lancet,’ Feb., 1875.--_Pareira, A. P._, “On Bilharzia and
Chyluria,” ‘Gazeta Med. da Bahia,’ No. 9, 1877 (noticed in ‘Lancet,’
Feb. 2, 1878).--_Salisbury, J. H._, “On the Parasitic forms developed
in Parent Epithelial Cells of the Urinary and Genital Organs,” ‘Hay’s
American Journ.,’ vol. iv, 1868, p. 376.--_Santos, F. dos_, in ‘Gaz.
Med. da Bahia,’ March, 1877.--_Sonsino, P._, ‘Richerche,’ &c., 1874;
‘Della Bilharzia,’ &c., 1876; ‘Sugla Ematozoi,’ &c., 1876 (see Bibl. No.
12).--_Idem_, “On the Diagnosis of Embryos of Filaria,” in his paper
‘Sull’ Anchylostoma duodenale;’ ‘Estr. dall Imparziale,’ 1878.--_Sousa,
M. de A._, ‘Memoria sobre a Elephantiasis do escroto,’ Bahia,
1878.--_Wucherer, O._, “Noticia Preliminar,” &c., ‘Gaz. Med. da Bahia,’
Dec., 1868.--_Idem_, ‘Sobre Hematuria no Brazil,’ _ibid._, Sept., 1869;
see also “Méricourt’s trans. (De l’hématurie intertropicale observée au
Brézil),” ‘Arch. de Méd. Nav.,’ p. 141, 1870, and the fuller references
quoted in my memoir; ‘Linn. Soc. Journ., Zool.,’ vol. xiv, p. 368.

_Filaria Loa_, Guyot.--Although further examinations of this worm will
probably result in placing it in some other genus than _Filaria_, yet
it is by no means clear that Diesing was right in placing it with the
genus _Dracunculus_. I therefore abandon the nomenclature adopted
in my previous treatise. According to the surgeon, Guyot, who made
seven separate voyages to the coast of Angola, these worms cannot be
confounded with the Dracunculus. They are quite white, and relatively
much thicker than guinea-worms. Under the title of _Filaria oculi_
Moquin-Tandon has spoken of certain small nematodes as “not uncommon
in the negroes of the Angola coast;” and he gives other localities
where it occurs. The worms are identical with those described by Guyot
as dwelling beneath the conjunctivæ of negroes at Congo and in the
Gaboon region generally. The parasite is rather more than an inch and
a quarter in length, being pointed at one end and blunt at the other.
It is termed _Loa_ by the natives, who state that after a period of
several years the worm voluntarily quits the organ. The disease is thus
naturally cured. This parasite enjoys a tolerably wide geographical
distribution, as it has been observed by Clot Bey in a negress who
had come from the town of Monpox, situated on the banks of the River
Magdalena; by Sigaud, who saw one in the eye of a negress in Brazil; by
Blot, at Martinique, who saw two in a negress originally from Guinea;
by Bajon, who met with one in a little negro girl who had come from
Guadeloupe; by Mongin, who found one in a negress who had been living
in the Island of San Domingo; and by Lestrille, who removed one from
beneath the conjunctiva of a negro who came from Gaboon.

BIBLIOGRAPHY (No. 24). _Davaine_, l. c., p. 839.--_Guyon_, ‘Gaz. Méd. de
Paris,’ p. 106, 1841, and in ‘Micr. Journ. and Struct. Record,’ p. 40,
1842, and in ‘Dublin Journ.,’ vol. xxv, p. 455, 1839.--_Idem_, ‘Compt.
Rendus,’ tom. lix, p. 743, 1865.--_Guyot_, in ‘Mém. par Arrachait,’ p.
228, 1805.--_Küchenmeister_, l. c., s. 322.--_Lestrille_, in Gervais and
Van Beneden’s ‘Zool. Med.,’ 1859, also quoted by Davaine, l. c., 2nd
edit., p. 840.--_Leuckart_, l. c., s. 619.--_Moquin-Tandon, A._, ‘Zool.
Med.,’ Hulme’s edit., p. 363, 1861.

_Filaria lentis_, Diesing.--This is a doubtful species. The worm
was first discovered by Nordmann, in a case of lenticular cataract
under the care of Von Gräfe, and it was afterwards found by Jüngken
in a similar case, as recorded by Sichel. There is also the instance
described by Gescheidt, in which Von Ammon operated, and from which
brief descriptions of the worm have generally been taken. In this case
there were three worms, two measuring about 1/6″ and the third 1/15″ in
length. In Jüngken’s case (exhibited by Quadri, of Naples, at Brussels)
the worm was more than 3/4″ long. In another case, reported by M. Fano,
the worm was somewhat less than 1/4″ long. There is no certain evidence
that any of these various worms had developed sexual organs in their
interior. It is true that the reproductive organs were described in two
of the worms observed by Gescheidt; but after a due consideration of all
the facts I fear we must conclude that all the worms in question were
sexually-immature and wandering nematodes, possibly referable to Gurlt’s
_Filaria lacrymalis_, as Küchenmeister long ago suggested.

BIBLIOGRAPHY (No. 25).--_Cobbold_, ‘Entozoa,’ p. 332.--_Davaine_, l.
c., p. 821 _et seq._--_Diesing_, ‘Syst. Helm.,’ p. 625.--_Fano_, ‘Traité
des Malad. des Yeux,’ tom. ii, p. 498; and in ‘Rec. de Méd. Vét.,’ p.
140, 1869; quoted by Davaine, p. 831.--_Gescheidt_, Ammon’s ‘Zeitsch.,’
1833, s. 435.--_Leuckart_, l. c., Bd. ii, s. 622.--_Nordmann_, l. c.,
Bibl. No. 2, s. 7, 1832.--_Sichel_, ‘Iconogr. Ophth.,’ p. 707, 1859.

_Filaria labialis_, Pane.--This is a filiform cylindrical worm measuring
an inch and a quarter in length. The mouth is armed with four papillæ
arranged in the form of a cross. The tail of the female is blunt, the
vaginal outlet being placed at a very short distance from its extremity,
and a little above or in front of the anus. This parasite was found by
a medical student at Naples. It occupied the cavity of a pustule in the
upper lip, giving rise to considerable irritation. Only the male worm is
at present known.

BIBLIOGRAPHY (No. 26).--_Davaine_, l. c., edit. ii, Synopsis, p.
107.--_Leuckart_, l. c. (with a fig.), Bd. ii, s. 616.--_Pane_, “Nota
di un elminte nematoide,” in ‘Annali dell’ Acad. degli aspiranti
Naturalisti,’ Napoli, ser. 3, vol. iv, 1864.

_Filaria hominis oris_, Leidy.--In the fifth volume of the ‘Proceedings
of the Philadelphia Academy of Natural Sciences’ (1850, p. 117) Dr Leidy
furnishes the following description of this worm as gathered from the
examination of a simple specimen preserved in alcohol, and labelled as
having been “obtained from the mouth of a child.” Body white, opaque,
thread-like; mouth round, simple; posterior extremity obtuse, furnished
with a short, curved, epidermal hooklet, 1/500″ in length, by 1/2000″
in diameter at base. Dr Leidy offers some speculations as to its origin,
but from whatever source the worm was obtained by the bearer, it seems
to be an immature form. Its length is five inches and seven lines.

_Filaria_ (_Nematoideum_) _trachealis_, Bristowe and Rainey.--This
is another very doubtful worm. It was originally described in the
‘Pathological Society’s Transactions’ for 1855. It evidently represents
only a juvenile stage of growth of some species of round worm. Rainey
discovered a considerable number of these worms in the trachea and
larynx of a person who died from a disease affecting the lower
extremities. Individually the parasites measured about the 1/50″ in
length.

_Strongylus_ (_Filaria_) _bronchialis_, Rudolphi.--This is a small
nematode. The male measures rather more than half an inch, whilst the
female is upwards of an inch in length. The caudal appendage of the
male is furnished with a bilobed, membranous, half-bell-shaped bursa.
This surrounds the cloacal outlet, the latter concealing a double
spiculum. The tail of the female is sharply pointed, the anal orifice
being placed a little in front or above. The body is filiform, of a pale
yellow color. It is about 1/50″ broad in the male, and 1/35″ in the
female. The mode of reproduction is viviparous.

The original specimens were discovered by Treutler in Germany, during
the winter of 1791, in the bronchial glands of an emaciated subject,
whilst those sent to Diesing for description were discovered by Dr
Fortsitz at Klausenberg, in Transylvania, in the lungs of a boy six
years old. Diesing and Weinland suggested the identity of _Filaria
bronchialis_ and _Strongylus longevaginatus_, whilst Küchenmeister went
further, and pronounced them to be one and the same species.

BIBLIOGRAPHY (No. 27).--_Cobbold_, ‘Entoz.,’ p. 357.--_Davaine_,
‘Synops.,’ l. c., ‘Synopsis’ cix.--_Küchenmeister_, l. c., Eng.
edit., p. 381.--_Leuckart_, l. c., s. 618.--_Treutler, F. A._, “De
vermibus filiformibus (_Hamularia lymphatica_) in glandulis conglobatis
bronchiorum repertis,” in ‘Obs. Pathol. Anat.,’ 1793.--_Wedl._, ‘Die im
Menschen vorkommenden Helminthen’ (quoted by Leuckart), Wien, 1862, s.
22.

_Eustrongylus gigas_, Diesing.--This is by far the largest nematode
known to science, the male sometimes measuring a foot in length and the
female more than three feet, whilst the breadth of the body reaches half
an inch at the thickest part. Though fortunately very rare in man, this
worm is known to occur in a great variety of animals, especially in
weasels. According to Weinland and Jackson, it is particularly abundant
in the kidney of the North American mink (_Mustela vison_), destroying
the substance of the organ, the walls of which become the seat of
calcareous deposit. It has been found in the dog, wolf, puma, glutton,
raccoon, coati, otter, seal, ox, and horse.

The body of the adult worm is cylindrical, more or less red in color,
and somewhat thicker behind than in front. The head is broadly obtuse,
the mouth being supplied with six small, wart-like papillæ, two of which
correspond with the commencement of the two lateral lines of the body.
These lines are also distinguishable from other six longitudinal lines
traversing the body from end to end by the presence of very minute
papillæ which are less closely arranged towards the centre (Leuckart).
The tail of the male shows a simple, thick, cup-shaped bursa, which is
destitute of rays, and partly conceals the simple spiculum. The tail of
the female is blunt and pierced by the centrally placed anal opening.
The vulva is situated near the head in the ventral line. The eggs are
stout and oval, measuring 1/300″ in length by about 1/550″ in breadth.

As regards development the recent researches of Schneider have shown
that certain kinds of fish play the part of intermediary bearer.
Balbiani preserved the ova in water for more than a year without their
hatching, and all his attempts to rear the larvæ in the intestines of
the dog by direct experiment failed. Similar feeding experiments upon
fishes and reptiles also failed. The embryo, when removed from the
egg, measures 1/104″ in length. It is vermiform, having a pointed head
and simple mouth. Balbiani describes the buccal cavity as containing
a protractile stylet. Notwithstanding the negative results obtained
by Balbiani’s experiments on fishes, Schneider (from anatomical data,
which Leuckart confirms) has placed it almost beyond question that
the worm hitherto known as _Filaria cystica_ is the sexually-immature
_Eustrongylus gigas_. This worm is found encysted beneath the peritoneal
membrane in _Galaxias scriba_ and _Synbranchus laticaudatus_. It is
worthy of remark that the genus Galaxias comes nearer to the Salmonidæ
than to the pike family, whilst the Synbranchi are tropical oceanic
fishes. Probably the sexually-immature worm occurs in other fishes,
especially the Salmonidæ.

Remarkably fine examples of the adult worm may be seen in the Hunterian
Collection, Lincoln’s Inn, and in the Museum of the Royal Veterinary
College. The human example is undoubtedly genuine. The dissections in
the Hunterian Collection of specimens were made by me in 1865. Objection
has been taken to my description of the œsophagus as “spiral.” In
Sheldon’s specimen it is certainly twisted upon itself, precisely in
the manner in which Davaine has also figured it (‘Traité,’ fig. 68);
but I cannot here give further anatomical particulars. Drelincourt
found two worms sexually united in the kidney. When once the parasites
have gained access to this organ, rapid destruction of the glandular
substance follows. Ultimately the kidney is reduced to the condition of
a mere cyst or bag, which, besides the worms, contains a quantity of
sanguineo-purulent matter. Frequently only one worm is present, but
oftener two or three. In the kidney of a puma D’Azara’s friend, Noseda,
found no less than six worms, whilst Klein obtained eight from the
kidney of a wolf.

BIBLIOGRAPHY (No. 28).--_Azara, F. de_, ‘The Natural History of the
Quadrupeds of Paraguay,’ trans. from the Spanish by W. P. Hunter;
Valpy’s edit., p. 43, 1837; Black’s, 1838; French edit., p. 313,
1801.--_Albers_, ‘Beitr. z. Anat. &c.,’ Bd. i, s. 115.--_Aubinais_,
‘Revue Méd.,’ 1846, p. 284.--_Balbiani_, “Recherches,” &c., ‘Compt.
Rend.,’ 1869, p. 1091; ‘Rec. de Méd Vét.,’ 1870, p. 5.--_Bickford_,
“Spec. of _Str. gigas_ found in the Kidney of a Dog,” the
‘Veterinarian,’ 1859, p. 312.--_Blainville_, ‘Dict. des Sci. Nat.,’
tab. 29.--_Blanchard_, ‘Ann. des Sci. Nat.,’ 1849, p. 186.--_Idem_, in
‘Cuvier’s Règne Animal’ (Masson’s edit.), ‘Les Intestinaux,’ p. 57,
pl. 27.--_Blasius_, ‘Obs., &c.’ (with fig. of Lumbricus in renibus
hominis), 1674, p. 125.--_Bobe-Moreau_, in ‘Journ. de Méd.,’ tom.
xlvii.--_Boerhaave_, ‘Aphorism.,’ 1728.--_Bremser_ (l. c., Bibl. 2),
s. 223.--_Chabert_, ‘Traité des maladies verm. dans les Animaux,’
1782.--_Chiaje_, ‘Comp. d. Elmintogr. umana,’ p. 106.--_Clamorgan, J.
de_, ‘La Chasse de Loup,’ 1583 (quoted by Davaine, the worms being
described as “serpents et bêtes fort venemeuses”).--_Cobbold_, ‘Entoz.,’
p. 358.--_Idem_, ‘Catalogue of Entozoa in the Museum of the Roy.
Coll. of Surg.,’ “Descr. of preps. Nos. 19-25,” p. 3, 1866.--_Idem_,
“Parasites of Man,” ‘Midland Naturalist,’ Dec., 1878.--_Collet-Meygret_,
“Mém. sur un ver trouvé dans le rein d’un Chien,” in ‘Journ. de
Physique,’ &c., 1802.--_Cuvier_, see _Blanchard_ (supra).--_Idem_,
‘Voyage en Sicile,’ and in ‘Ann. des Sci. Nat.,’ tom. xi.--_Davaine,
C._, ‘Traité,’ l. c., deuxième edit., p. 271 _et seq._ (with full lit.
refs. at p. 290).--_Diesing_, l. c., vol. ii, p. 325.--_Dujardin_, l.
c., p. 113.--_Frank, F._, “Ein Spulwürm in der Urinblase eines Hundes,”
‘Hufeland’s Journ.,’ Bd. xviii, s. 112.--_Jackson_, ‘Catalogue of the
Boston Museum,’ 1847, p. 317.--_Klein, T. K._, “Anatomical Description
of Worms found in the Kidneys of Wolves,” ‘Phil. Trans.,’ 1729-30, p.
269.--_Küchenmeister_, l. c., Eng. edit., p. 376.--_Leblanc_ (rep. by
Rayer and Bouley), in ‘Bull. de l’Acad. de Méd.,’ 1850, p. 640; in ‘Rec.
de Méd. Vét.,’ 1862, p. 800; and quoted by Davaine.--_Leuckart_, l. c.,
Bd. ii, s. 353-401, 1876.--_Moublet_, “Mém. sur les vers sortis des
reins et de l’urethre d’un enfant,” ‘Journ. de Méd-Chir. et Pharm.,’
1758, pp. 244 and 337.--_Otto_ (Anat.), in ‘Mag. d. Gesellsch. naturf.,’
1814.--_Owen_, art. “Entozoa,” in Todd’s ‘Cyclop.’--_Rayer_, ‘Traité
des maladies des reins,’ 1841.--_Rayger_, ‘Sur un serpent qui sortit
du corps d’un homme après sa mort’ (quoted by Davaine, l. c., p. 272),
1675.--_Schneider_, ‘Monographie der Nematoden,’ 1866, s. 50.--_Idem_
(mit Peters), quoted by Leuckart, l. c., s. 382.--_Stratton_, in ‘Edin.
Med. and Surg. Journ.,’ p. 261, 1843.

_Dochmius duodenalis_, Leuckart.--Much time might be occupied and wasted
over the nomenclature of this parasite. In my previous treatise, and
for reasons there stated, I placed it under the genus _Sclerostoma_.
On rather slender grounds Dubini formed the genus _Anchylostoma_
for its reception, but Von Siebold thought that, on account of the
absence of symmetry in the arrangement of the so-called dental organs,
Dubini’s genus might very well be allowed to remain. Bilharz, Diesing,
Küchenmeister, Wucherer, and others have retained the genus as either
_Anchylostoma_ or _Anchylostomum_. Schneider keeps it amongst the
_Strongyli_; but after all that has been said and written there can,
I think, be no doubt that if Dujardin’s genus _Dochmius_ is to be
retained at all, Dubini’s worm must be placed in it. The comparisons
instituted by Leuckart afford sufficient proof of the intimate alliance
as between _Anchylostoma_ and _Dochmius_. Professor Molin thought to
meet the difficulty by calling the worm _Dochmius anchylostomum_, but
the specific term, _duodenale_, should certainly be retained.

This worm was discovered by Dubini at Milan, and though at first thought
rare, it is now known to be tolerably common throughout Northern Italy.
The worm has also been recently found by Dr Kundrata at Vienna, in an
Austrian subject. According to Pruner, Bilharz, and Griesinger, it
is abundant in Egypt. Griesinger believed that about one fourth of
the people of that country suffered from anæmic chlorosis, solely in
consequence of the presence of this worm in the small intestines. From
Wucherer’s observations especially, we know that Dubini’s worm is not
limited to the localities above mentioned, for it occurs in the western
tropics, in Brazil, and even in the Comoro Islands.

The worm may be described as a small nematode, the males measuring 3/8″
or rather more, whilst the females extend to very nearly 1/2″ (12 mm.).
The head is pointed and tapering, and bent forward, having the mouth
directed towards the ventral aspect. The oral opening is armed with four
asymmetrically disposed, unequally-sized, horny, conical, converging
teeth. The neck is continuous with the cylindrical body, which is 1/80″
in thickness. The body terminates in a straight cone-shaped, or rather
sharply-pointed tail in the female, the caudal extremity of the male
ending in a partially inflexed, blunt point. In the male there is a
cup-shaped, bilobed bursa, the membranes of which are supported by
eleven chitinous rays, ten being simple, whilst the median, or odd one,
is bifurcated at the summit. The mode of reproduction is viviparous.
Adult males and females occur in the proportion of one of the former to
three of the latter.

[Illustration: FIG. 41.--Male _Dochmius duodenalis_, with bursa
separately enlarged. After Küchenmeister.]

As above mentioned, it was Griesinger who first pointed out the clinical
importance of this entozoon. He first explained the manner in which
the worm produces anæmia, the persons attacked losing blood as if
they were being bitten by innumerable small leeches. Like the rest of
their kindred, these worms are veritable blood-suckers. In the first
instance the views of Griesinger met with opposition, but they have
since received abundant confirmation. Whilst Küchenmeister’s ‘Manual’
furnishes an excellent account of the disorder as known in Europe, we
are chiefly indebted to Wucherer for what is known of the disorder in
Brazil. The experiences recorded in the ‘Deutsches Archiv für Klinische
Medicin’ for Sept. 27th, 1872 (s. 379-400), were amongst the last that
appeared from the pen of that gifted and amiable physician. As little
or no notice of his writings appears to have been taken by professional
men in this country, I depart somewhat from the design of this work
when I venture to abstract a few of the clinical particulars which
he has supplied. Their importance in relation to sanitary science is
obvious, inasmuch as these parasites are introduced into the human body
by drinking impure water, or, at least, water which either contains the
free larvæ of the worm, or the intermediary bearers that harbor the
larvæ.

It should be borne in mind that Dubini’s original discovery was made at
Milan in 1838, whilst Griesinger’s recognition of the worm as a cause
of the Egyptian chlorosis resulted from a post-mortem examination made
on the 17th of April, 1851.

In the journal above mentioned, Wucherer records his own discoveries
as follows (‘Ueber die Anchylostomunkrankheit,’ &c.):--“Although
Griesinger with well-founded confidence gave an account of his ‘find’
and its significance, yet it remained for a long time unnoticed and
unutilised, till at length a case led me to corroborate it. During my
many years’ residence in Brazil, especially during the first year, I
had very frequent opportunities for witnessing the tropical chlorosis,
but seldom to treat it, as it is one of those diseases for which
Brazilians seek no medical assistance. Its treatment falls to the lot
of the _curiosos_, _curadeiros_ (quacks), who employ the fresh pulp of
a species of fig as a remedial agent with the best results. On the 13th
of December, 1865, I was called to the Benedictine monastery in Bahia
to see a slave of the _order_ suffering from _hypoæmia_. The patient
was about thirty years of age, married, a strongly built mulatto. He
was a field laborer on the Ingua plantation of the order, who exhibited
in a conspicuous degree all the symptoms that occur in hypoæmia except
the diarrhœa. He was well nourished, but strikingly pale, his whole
face, but especially the eyelids, being œdematously swollen, as also
were the feet, legs, and hands. The hands and feet were very cold.
His appearance betrayed the most horrible anguish or low despondency.
With difficulty only could he raise himself, being obliged to lie down
again immediately on account of his weakness. Auscultation revealed a
diminished respiratory murmur, and bronchial expiration in both lungs.
The pulse was very rapid and small, the patient complaining of pain in
the region of the heart. He had frequent palpitation when he moved, and
he complained of pain in other parts of the body. His abdomen was much
distended by gases, but not sensitive to pressure from without, except
in the region of the stomach. The urine was clear, its specific gravity
1007 to 1023-1/2°. Under great difficulties he resided for several
months after his marriage at Inhatâ. Earlier he had been on the estates
of the order at Rio de S. Francisco. He there suffered for a long time
from intermittent fever, but at Inhatâ he entirely recovered. At Inhatâ
the slaves frequently suffered from hypoæmia, but in S. Francisco not
at all. He appears not to have made any misuse of brandy. The slaves
of the order were well cared for, and supplied with good and wholesome
nourishing food. The patient had already, for a long period, treated
himself with steel wine, yet was continually getting worse and worse.
He had not taken the pulp of the fig. As I was unaware he had suddenly
become so ill, they hastily despatched a message to the town. There was
no good to be expected from the further employment of iron, and the
patient was in such a condition that from the very first I despaired
of his recovery. I immediately prescribed the pulp of the Gammeleira
(_Ficus doliaria_), but it could not be easily obtained. Considering
that the Gammeleira would have a drastic effect, I therefore prescribed
two grammes of elaterium, to be divided into eight doses, of which he
should take one every three hours.” Dissatisfied with this advice,
however, Dr Wucherer goes on to say that on reaching home he carefully
looked up the literature of the subject. “In a ‘Geologico-Medical
Report’ by Professor Hirch, recorded in the ninety-sixth volume of
‘Schmidt’s Jahrbucher,’ I found how Griesinger had recognised the
_Anchylostoma_ as the cause of the Egyptian chlorosis, which was
clearly identical with our _hypoæmia_. He had employed this commended
anthelmintic. I resolved the more to prescribe the pulp of the
Gammeleira when I found it described as a worm-expelling remedy in
Martin’s ‘Systema Materiæ Vegetabilis Braziliensis.’ The next morning,
however, when I arrived at the monastery I learnt that my patient died
about two hours after a slight evacuation. Only after much resistance
would they permit the _sectio cadaveris_. I merely opened the abdomen,
and was surprised to find everything as Griesinger had described. During
the next season, through the courtesy of my colleagues attached to the
General Infirmary at Bahia, especially of Drs Silva Lima, Faria, and
Caldos, I was enabled to open more than twenty bodies of anæmically
deceased individuals. All were selected as miserably poor in condition,
but only five were bodies of persons in whom hypoæmia was diagnosed,
and in these there were a great number of Anchylostomes in the small
intestine. The intestines of the other bodies contained either none,
one, or a few.” Dr Wucherer next states that he compared the characters
presented by his entozoa with those given by Dubini, Diesing, and Von
Siebold, and found a perfect agreement throughout. He sent several
examples to Griesinger, who also established their identity, and
communicated the results of his investigations accordingly (‘Archiv für
Heilkunde,’ 1866, s. 387. See also Leuckart, ‘Die Mensch. Par.,’ Bd ii,
s. 411). Dr Wucherer also forwarded a number of specimens to Dr Weber,
who published a brief account of them with excellent figures (‘Path.
Soc. Trans.,’ vol. xviii, 1867, p. 274). As mentioned in the text of
his memoir (s. 394), Dr Wucherer also transmitted some strongyloids to
myself. “The publication of my observations,” adds Dr Wucherer (‘Gazeta
Medica da Bahia,’ 1866, p. 27 _et seq._), “had a result in that Dr J.
R. de Moura, of Thersepolis, in the province of Rio de Janeiro, sought
for Anchylostomes in the bodies of tropical anæmics (_Hypöæmikern_).
He at once found these parasites, as stated in the same journal (for
1866, p. 132). As occurred to myself, he saw no enduring results from
the application of the remedies which appeared to be called for, whilst
he well knew that unprofessional persons (Nichtärzte) succeeded in
obtaining marked results by the exhibition of the pulp of the Gammeleira
(_Ficus doliaria_). The anthelmintic action of this remedy was also
unknown to him.” Dr Wucherer then records how his discovery of these
entozoa was announced by Dr Jobini to the Rio academy, and how Dr
Moura’s observations were subsequently communicated, adding remarks upon
the interesting discussion that followed. The general opinion was that
the _Anchylostomata_ were _not_ the primary and necessary cause of this
tropical anæmia, but rather a co-operating agent in its production.
Against this view Dr Wucherer afterwards very properly protested
(‘Gazeta,’ Jan. 15th, 1868). In the mean time, says our author, “Dr le
Roy de Méricourt, prompted by my first communication, had invited the
physicians of the French colony to seek for Anchylostomes. Drs Monestier
and Grenet, at Mayotta (one of the Comoro Isles, which lies about 12°
S. lat. to the north-east of Madagascar), ascertained the presence of
entozoa in hypoæmics. Dr Grenet sent the duodenum and a portion of the
jejunum of an hypoæmic corpse to Le Roy de Méricourt, who compared
the Anchylostomes with Davaine’s description, and recognised them as
examples of _A. duodenale_.”

“In the year 1868 Dr Rion Kérangel found Anchylostomes in the bodies
of hypoæmics in Cayenne. Thus, the occurrence of Anchylostomes in
hypoæmics has been authenticated by Pruner, Bilharz, and Griesinger,
in Egypt; by myself, Dr Moura, Dr Tourinho, and other physicians, in
Brazil; by Monestier and Grenet, in the Comoros; and by Rion Kérangel in
Cayenne. It thus also appears, from the wide separation of these several
localities, that the Anchylostomes, if duly sought for, will be found in
many other countries.”

These details given by Wucherer are so precise and instructive that I
could not have further abridged them without injustice to his record.
The bearing of the foregoing facts in relation to the question as to
how we may hope to arrest the fatal action of many of these nematodes
is sufficiently obvious. That strongyles and their allies prove highly
destructive to man and beast is as well established as any other
recognised conclusion in medical science; nevertheless, there are
those who still doubt the power of these nematodes in relation to the
production of fatal epidemics. I shall deal with the sanitary bearings
of the subject hereafter. In conclusion, I may mention that Dr da Silva
Lima has forwarded specimens of _Anchylostomum_ to the Hunterian Museum,
where they may be seen.

BIBLIOGRAPHY (No. 29).--_Bilharz_, ‘Zeitschr. f. wiss. Zool.,’ Bd.
iv, s. 55.--_Cobbold_, ‘Entozoa,’ p. 361.--_Idem_ “Remarks on Recent
Contributions to our Knowledge of the Parasitic Nematoids, especially
in reference to the Wasting Diseases they produce in Man and Animals,”
the ‘Veterinarian,’ Jan., 1876, p. 1.--_Davaine_, l. c., pp. 118
and 931.--_Diesing_ “Revis. der Nematoden,” ‘Sitzb. d. m.-naturw.
cl. d. k. Akad.,’ 1860, s. 716.--_Dubini_, ‘Entozoografia,’ &c.,
1849.--_Griesinger_ (quoted above), see also ‘Arch. f. Phys. Heilk.,’
1854.--_Küchenmeister_, l. c., Eng. edit., p. 383.--_Leuckart_, l.
c., ss. 410-455.--_Molin_, ‘Il sottordine degli Acroffali,’ p. 61
(quoted by Leuckart).--_Siebold_, ‘Zeitsch. f. wiss. Zool.,’ 1852,
s. 55.--_Sonsino, P._, _L’Anchilostoma duodenale_ in ‘relazione
coll’ Anemia progressiva perniciosa,’ Egitto, 1877.--_Idem_, ‘Sull.’
_Anch. duod._, 1878 (see also Bibliog. No. 27, both reprinted from
‘Imparziale.’)--_Weber, H._, l. c., 1867.--_Wucherer_ (quoted above),
1872.

_Dracunculus medinensis_, Cobbold.--This parasite is popularly known as
the guinea-worm, or Medina-worm. Probably Lister was the first writer
who distinctly spoke of it as the Dracunculus, 1690, the same title
being applied to it by Kaempfer, 1694. Be that as it may, Gmelin, long
afterwards, placed the parasite in the genus _Filaria_, at the same
time adopting the specific title _medinensis_. This had been previously
employed by Linneus, who, however, regarded the worm as belonging to the
genus _Gordius_. It being clear from the distinctive characters of the
entozoon that it was desirable to separate it from the Filariæ, and that
no better generic name could be devised than _Dracunculus_, I thought
it right to combine Lister’s and Gmelin’s nomenclature as above, 1864.
Leuckart pursued a similar course, crediting Linneus with the titles.

The guinea-worm having been known from the earliest times, it is not
surprising that its true nature long remained a mystery. Any one who has
read Küchenmeister’s elaborate narrative of the historical significance
of the Dracunculus will hardly have failed to arrive at the conclusion
that Moses was probably the earliest writer on the endemic disorder
which is occasioned by this parasite. There can be no doubt that the
“fiery serpents” which afflicted the children of Israel during their
stay in the neighbourhood of the Red Sea were neither more nor less
than examples of our Dracunculus. It is further evident that Plutarch
spoke of Dracunculi, when in the eighth book of his ‘Symposiacon,’ he
quotes Agatharchidas as stating that the people taken ill on the Red
Sea suffered from many strange and unheard-of attacks, amongst other
worms, from “little snakes, which came out upon them, gnawed away their
legs and arms, and when touched retracted, coiled themselves up in
the muscles, and there gave rise to the most insupportable pains.” In
order to render the passage more readable, it will be seen that I have
slightly altered the original version (‘Parasites,’ s. 305).

The guinea-worm may be described as a nematode measuring from one to six
feet in length, having a thickness of 1/10th of an inch. The body is
uniformly cylindrical, terminating below in a more or less curved and
mucronately pointed tail. The head is flatly convex or truncate, having
a central, simple mouth, which is surrounded by four equi-distantly and
cruciately disposed papillæ. The mode of reproduction is viviparous,
the body enclosing a prodigious number of hatched embryos, which, by
distension of the uterine ducts, almost entirely obliterate the somatic
cavity. Notwithstanding the statements of Owen to the contrary, the male
Dracunculus is at present altogether unknown.

[Illustration: FIG. 42.--Outline of a female _Dracunculus medinensis_.
Nat. size. Original.]

The guinea-worm possesses a comparatively limited geographical
range, for not only is it proper to the tropical regions, but within
intertropical limits it is almost exclusively confined to certain
districts in Asia and Africa. Thus, according to Künsenmuller, as quoted
by Busk, it occurs endemically in Arabia Petræa, on the borders of the
Persian Gulf and Caspian Sea, on the banks of the Ganges, in Upper
Egypt, Abyssinia, and the coast of Guinea. “In America the guinea-worm
is unknown, except in persons who have had communication with Africa
or other parts where it is indigenous. The island of Curaçoa is the
only locality in the New World which offers an apparent exception to
this fact, and it would be highly desirable to ascertain the real state
of the case in this instance.” The observations of Chisholm showed
that the Dracunculus is really prevalent in several of the West Indian
islands, especially in Grenada, and the still later investigations of Dr
Da Silva Lima point to its former prevalence in Brazil. Now, the worm
is rarely seen at Bahia. Mr Busk said:--“Though endemic only in the
above-mentioned parts of the world, it would yet appear that all races
of mankind are obnoxious to the attacks of the _Filaria_ when exposed to
what may be called the contagion; that is, when placed in circumstances
under which it might be supposed a contagious _seminium_ could be
conveyed to them.” Mr Busk also added:--“I have known many instances
tending to prove that, in order that a European should become infected
with the guinea-worm on the coast of Africa, it is not necessary that
he should have been on shore at all. It has been quite sufficient for
him to have exposed the bare surface of some parts of his person to the
water in the native canoes alongside, or, it may be, to the discharge
from the sores of those laboring under the disease. This mode of its
introduction accounts for the frequency with which the legs and feet
are attacked by the parasite, in preference to other parts of the body,
as it will always, I believe, be found that the men who have become so
affected have been in the habit of going about with bare feet, as is
common among sailors in warm latitudes. That the contagious material is
conveyed in water is also further indicated by the well-known fact that
in India, where it is the custom of the natives to carry water in skins
on their backs, the worm makes its appearance on the back and shoulders
and upper part of the body.” These views were published by Busk in
1846, and I am free to confess that--confirmed as they appeared to be
by subsequent and independent testimony--they completely dominated my
conceptions as to the mode of ingress of the young parasites within the
human bearer. Thus, those of our Indian troops which were most exposed
during the rainy season, subsequently exhibited evidence of having been
invaded by the Dracunculus. As, moreover, the period of incubation
of the entozoon commonly extends from twelve to fifteen months, it
necessarily happened that the disease often showed itself in localities
far distant from the spot where the troops originally contracted the
disorder. The statement that the period of incubation of the worm is not
less than a year, is probably incorrect, since Carter mentions that in a
school of fifty boys bathing in a certain pond at Bombay--the sediment
of which swarmed with microscopic tank-worms (_Urobales palustris_,
Carter)--twenty-one were attacked with Dracunculus during the year,
whilst the boys of other schools, bathing elsewhere, remained, with few
exceptions, uninfected. This is a remarkable occurrence, and it points
to the possibility of the young Dracunculi being confined to particular
pools. That they should, whether occupying the bodies of intermediary
bearers or not, be more abundant in some waters than others, is just
what might be expected, since such a distribution is in harmony with
a recognised law affecting the abundance or limitation of species in
particular localities. Much, indeed, has been written respecting the
nature of the soil and geological formations occurring in the Indian
worm-districts, but the speculative views enunciated on this point are
little worthy of credit. Those who desire information on this head
should at all events consult the valuable writings of Smyttan, Greenhow,
Bird, Forbes, Chisholm, and Aitken, who, apart from the question at
issue, supply abundance of practical information.

[Illustration: FIG. 43.--_a_, _b_, Head and tail of the adult
guinea-worm (magnified 10 and 18 diameters respectively); _c_, embryo
(magnified 500 diameters). Original.]

Into the anatomy of the adult Dracunculus I do not enter, but I may
remark in passing, that the structure of the worm has been exhaustively
treated of by Busk and Bastian. A _résumé_ of their views is given in
my introductory treatise. Carter and Leuckart have also added important
details. As regards the structure and development of the young
worms, I have to observe that the discovery of the viviparous mode of
reproduction in Dracunculus is due to Jacobson. Nearly a quarter of a
century ago I recognised the fact that the uterine organs of the adult
worm almost completely filled up the perivisceral cavity, and that
they were crowded with microscopic worms. Referring to this “find,”
the late Sir George Ballingall, of Edinburgh, in his well-known work
on ‘Military Surgery,’ recorded the circumstance in the following
terms:--“The Assistant Conservator of the Anatomical Museum in our
University has detected _in the oviduct_ of an adult specimen from
my collection myriads of minute and perfectly-developed (embryonic)
Dracunculi. They can be very well seen with an half-inch object-glass,
but their structure is best exhibited if the magnifying power be
increased to two hundred and fifty diameters linear.” As already stated
in my introductory treatise, these observations were made during the
winter of 1853-54. In July, 1854, M. Robin made a similar statement
after examining a fresh _Dracunculus_ which had been extracted from the
leg of a man by M. Malgaigne. Robin, not unsuitably, compared the worm
to a double tube, one tubular sheath, as it were, enclosing the other.
“The second tube,” he distinctly affirms, “_is the oviduct, or, rather,
that part which represents the uterus_. The young still remaining in
the uterus were nearly all coiled, sometimes with the tail sallying
outwards, at others rolled like the rest of the body.” I have thought
it only due to Robin and myself to show that from the first we were
perfectly well acquainted with the fact of the “great development of the
genital tube and of its close adherence to the parietes of the body.”
To be sure, many discrepancies occurred in our writings, and in those
of Busk and Carter. It was Bastian’s skill and good fortune to correct
these errors. Thus, most of us agreed in recognising a slightly trilobed
or tripapillated mouth; but Carter failed to demonstrate the existence
of these tubercles, and spoke of the oral aperture as being simple and
“punctiform.” The body throughout its three upper fourths appeared to me
to be cylindrical, but Robin found that it was flattened. It is finely
striated transversely, except at the part where it contracts to form
the slender, pointed tail. According to Carter, Robin, and Davaine, the
young attain a length of about 1/33 of an inch, but Bastian gives it as
about 1/42″. In thickness, Carter gives the approximative diameter as
1/633″, Robin makes it 1/990″ to 1/1320″, whilst Bastian gives their
breadth at 1/1428″, and Davaine at 1/2500″. I estimated their greatest
length and breadth to be 1/30″ by 1/1000″. Robin and myself thought
we recognised a distinct, rounded, anal orifice; and whilst Busk, on
the one hand, saw nothing which in the slightest degree indicated the
presence of an anal opening, Carter, on the other hand, described the
structure which we called the anus as a gland, at the same time placing
the alimentary outlet on one side and a little above it. According to
Bastian, “the intestinal tube is about 1/87″ in length, and appears
to consist of a simple canal of varying calibre, pursuing a nearly
straight course, and terminating exactly at about the middle, in length,
of the worm.” Like Robin, Bastian recognised œsophageal and stomachal
divisions, and in a few examples he observed the cæcal or terminal
portion of the intestine to be partially reflected upon itself. In
regard to the circular opening which Robin and myself described as the
anus, Bastian says there is a rounded body, “about 1/2200″ in diameter,
with a dark or light spot in the centre, according to the varying focal
distance, and which seems to represent a central aperture. Sometimes,
above this, traces of two or three large cells may be recognised, whilst
behind nothing definite can be made out, save that the cavity of the
body is visible for about 1/400″. In other specimens of the young worm
the central body and spot are wanting, but, in its stead, two lateral
sacculi are met with, about 1/3300″ in diameter, that communicate
with the exterior by a minute channel through the integuments, which
can sometimes be distinctly recognised. At other times the channel is
obscured by protrusion, which appears to have taken place through it,
of a minute bilobed papilla, projecting 1/10,000″ from the side of the
body. When the projections are seen, the sacculi are indistinct.”

[Illustration: FIG. 44.--Embryos of _Dracunculus_. Magnified 500
diameters. After Bastian.]

As Bastian found the young in all stages of development from the
germ condition 1/5000″ in diameter up to the perfect embryo, and as,
moreover, he, like the rest of us, could detect no sexual orifice in
the adult Dracunculus, he was led to express his belief that the young
were produced agamogenetically. He went so far as to call the germs
_pseudova_. It was with great reluctance that I dissented from the views
of so gifted an observer as Bastian; nevertheless, later researches have
shown that I was justified in not hastily concurring in the theory of a
non-sexual mode of reproduction for Dracunculus.

Among the many advances of modern helminthology, the discovery of the
true source of the guinea-worm is not the least important. To the late
M. Fedschenko (the lamented and accomplished Russian traveller, who
lost his life in a snowstorm on the Alps), science stands indebted
for this memorable advance. Fedschenko showed that the embryos of
Dracunculi, after quitting the human host, succeed in effecting an entry
into the bodies of entomostracous crustaceans belonging to the genus
Cyclops. Within these intermediary bearers, after twelve hours’ sojourn,
the embryos undergo a change of skin, attended with subsequent growth.
Here they remain to complete their larval development, which takes place
within a period of five weeks, or, as Fedschenko himself told me, one
month and six days. At length, as perfected larvæ, they are, together
with their crustacean hosts, transmitted to the stomach of the ultimate
or human bearer. It is probable that sexual maturity is next acquired
within the human stomach, copulation following. After this, the females
migrate to the situations in which they are found beneath the skin of
the human bearer, whilst the males perish and pass out with the fæces.
Thus much I gathered from M. Fedschenko himself when he visited this
country, and I possess a sketch of the larvæ made by him at the time
(October 23rd, 1873). One of the figures represents a larva which has
undergone ecdysis, the long and narrow embryonic tail being supplanted
by one which is blunt and forked at the tip. The somatic contents of the
embryo have at the same time differentiated into a complete intestinal
tube, and a constriction marks the junction of the œsophagus with the
stomach. There is also internally an oval-shaped mass of cells near the
centre of the body. These represent the commencement of the reproductive
organs.

What I had gathered from Fedschenko in conversation thus epitomises
that which has since been much more fully stated by Leuckart; and
it is only fair to add that the Russian traveller was led up to his
discovery by the previous investigations of Leuckart respecting the
young of Cucullanus. The Leipsic helminthologist had, indeed, specially
instructed Fedschenko as to the probable source of Dracunculus.

It is often thus that science makes its clear advances, since a
master-mind is needed to set others on the right track. The embryos
of Cucullanus and Dracunculus bear a close resemblance to each other,
and the similarity of the types is continued on, though not in the
same degree, in the next stage of larval growth, after ecdysis. The
higher larvæ of both have their tails trifurcate at the tip, the head
of the Dracunculus-larva being distinguished by the presence of a pair
of papillæ. In the case of Cucullanus the embryos are, according to
Leuckart, passively transferred to the stomach of Cyclops by the mouth;
but in the case of Dracunculus, Fedschenko saw the embryo in the act of
perforating the bodies of the little crustacea at the ventral surface,
where the segments are bound together by a thin and easily penetrated
connecting membrane. The larvæ then proceed to coil themselves within
the limbs, as many as six or even a dozen of the parasites being
occasionally found within the body of a single crustacean host. When
they have reached full larval growth they measure about 1/25″ in length.
Of course, after attaining this stage, it is a matter of conjecture
as to the precise way in which their final destiny is accomplished.
Fedschenko fed dogs and cats with the infected crustacea, but failed
to rear Dracunculi in these animals. Clearly, these carnivora were
unsuitable hosts. Could Fedschenko have experimented on man the result
would probably have been very different. Arguing from what happens in
the case of Cucullanus amongst fishes, and Trichina in man, there can
be little doubt that all the further and final changes undergone by
the larvæ are accomplished within the human host. These changes are
usually, if not invariably, consequent upon a direct transference of the
infested entomostraca along with water used as drink. Thus, it must at
once be evident that the simple sanitary precaution of filtering water
before use is amply sufficient to ensure the prevention of attacks of
dracontiasis or the guinea-worm disease. The theosophical remedy of
Moses against this invasion by fiery serpents, as the worms were called
in his time, and the modern prophylactic measures dictated alike by
science and common sense, thus stand in striking contrast the one to the
other. In the nature of things it must ever remain that unreason and
reason will select diametrically opposite methods of action, equally, no
doubt, with the good intention of bringing about beneficial results.

From what has now been advanced, it will be seen that as regards the
mode of infection the views categorically expressed in my previous work
(‘Entozoa,’ p. 387) cannot be maintained. What, however, is there stated
in respect of _treatment_ still holds good in the main, even as regards
prophylaxis.

BIBLIOGRAPHY (No. 30).--_Adam_, ‘Trans. Med. and Surg. Soc.,’ Calcutta,
1824.--_Aitken, W._, ‘The Science and Practice of Medicine,’ 6th edit.,
vol. i, 1872.--(Anonymous), “Review of the writings and opinions
of Duncan, Johnson, Bird, Mylne, Kennedy, Chisholm, H. Scott, A. J.
Robertson, Smyttan, Macgregor, Thomas, Mosely, Morehead, Twining,
and others, on the Dracunculus or Guinea-worm,” in ‘Corbyn’s India
Journ. of Med. and Phys. Sci.,’ vol. ii, p. 118, 1836.--(Anon.),
“The Guinea-worm very Prevalent at Bokhara,” ‘Boston Med. and Surg.
Journ.,’ 1843, p. 387.--_Balfour, J._, ‘Ind. Ann. Med. Sci.,’ 1859, p.
175.--_Ballingall, G._ (l. c., supra), 1854.--_Bastian, H. C._, “On
the Structure and Nature of the Dracunculus or Guinea-worm,” ‘Linn.
Soc. Trans.,’ vol. xxiv, p. 101, 1863.--_Berncastle, J._, in the
‘Lancet,’ 1851.--_Bird, J._, ‘Calcutta Med. and Phys. Trans.,’ 1825,
p. 151.--_Bremser_ (l. c., Bibl. No. 2), s. 194.--_Brett_, ‘Surgical
Diseases of India,’ 1840; see also ‘Med.-Chir. Rev.,’ 1841.--_Bruce,
N._, ‘Edin. Med. and Surg. Journ.,’ 1806, vol. ii, p. 145.--_Busk,
G._, ‘Micr. Soc. Trans.’ (original series), 1846.--_Carter, H. J._,
“Note on Dracunculus in the Island of Bombay,” ‘Bombay Med. and Phys.
Soc. Trans.’ (new series), No. 2, p. 45, 1853-54; see also postscript,
p. 252.--_Idem_, “Further Observ. on Dracunculus,” ‘Bomb. Med. and
Phys. Soc. Trans.’ (new series), No. 4, p. 215, 1857-58.--_Idem_, “On
Dracunculus and Microscopic Filaridæ,” ‘Ann. of Nat. Hist.,’ vol. iv
(third series), 1859.--_Idem_, “Notes on Dracunculus,” &c., ‘Ann. of
Nat. Hist.,’ vol. ix (third series), 1862.--_Chapotin_, ‘Bull. des
Sci. Med.,’ 1810.--_Charvet_, ‘Ann. des Sci. Nat.,’ 1834.--_Chiaje_
(l. c., Bibl. No. 2), p. 99.--_Chisholm, C._, “On the _Malis
Dracunculus_ or Guinea-worm (in Grenada),” ‘Edin. Med. and Surg.
Journ.,’ vol. xi, 1815; see also the ‘Veterinarian,’ vol. ix, p. 508,
1836.--_Clark_, ‘Med.-Chir. Rev.,’ 1840.--_Clarkson, N. F._, “Alleged
Case in the Horse,” the ‘Veterinary Record,’ 1845, p. 73.--_Clot-Bey_,
‘Aperçu sur le ver dragonneau observé en Egypte,’ 1830.--_Cobbold_,
‘Entozoa,’ p. 373.--_Cuvier_, ‘Règne animal,’ Orr’s Eng. edit., 1849,
p. 644.--_Davaine_, ‘Traité,’ l. c., edit. ii, p. 783 (full lit.
refs.), 1878.--_Dickson_, ‘Path. Soc. Trans.,’ 1851.--_Drummond_,
‘Med. Commentaries,’ 1793, p. 294.--_Dubois_, ‘Edin. Med. and Surg.
Journ.,’ vol. ii, 1806.--_Duncan_, ‘Calcutta Med. and Phys. Soc.
Trans.,’ 1835.--_Ewart, J._, “Questions relating to Dracunculus,” in
a review of his memoir on the “Vital Statistics of the Meywar Bheel
Corps,” in the ‘Madras Quart. Journ. of Med. Sci.,’ vol. i, 1860, p.
462.--_Fedschenko_, ‘Protocol of the Promoters (Freunde) of the Natural
and Physical Sciences at Moscow’ (in the Russian language), 1869 and
1874 (quoted by Leuckart).--_Forbes, D._, “Observ. on Dracunculus”
(extr. from the ‘Half-yearly Reports of the diseases prevailing at
Dharwar in the 1st Grenadier Regiment, in the year 1836’), ‘Bombay Med.
and Phys. Soc. Trans.,’ vol. i, 1838, p. 215.--_Gibson, A._, “Note on
the Prevalence of Dracunculus,” in his remarks on the “Diseases of
the Deckan,” in ‘Bomb. Med. and Phys. Soc. Trans.,’ vol. ii, 1839,
p. 209.--_Gramberg_, ‘Geneeskundige tijdschrift voor nederl. Indie,’
1861, p. 632 (quoted by Leuckart).--_Greenhow, H. M._, ‘Indian Ann. of
Med. Sci.,’ vol. vii, 1861, p. 31.--_Grierson, D._, “Observ. on the
Dracunculus, as it prevailed in the 22nd Regiment, N.I., from April till
September, 1841,” ‘Bomb. Med. and Phys. Soc. Trans.,’ No. 4, 1841, p.
90.--_Grundler_, in ‘Commerc. Litt. Nov.,’ 1740, p. 239.--_Henderson,
J._, “Note respecting Four Cases of Dracunculus in the 48th Regiment,”
‘Madras Quart. Journ.,’ vol. iii, 1841, p. 353.--_Horton, J. A. B._,
‘Army Med. Reports,’ 1868, p. 335.--_Kennedy, R. H._, ‘Calcutta
Med. and Phys. Soc. Trans.,’ 1825, p. 165.--_Küchenmeister_ (l. c.,
Eng. edit.), p. 389.--_Leuckart_ (l. c., Bibl. No. 1), s. 644-725.--
_Lewis, T. R._, in ‘On a Hæmatozoon,’ &c. (l. c., Bibl. No. 23), p.
30 _et seq._--_Lima, Da S._, “Remarks on the _Filaria medinensis_, or
Guinea-Worm; on the occurrence of this Parasite endemically in the
Province of Bahia; on its entrance into the human body by drinking
water,” in the ‘Veterinarian,’ Feb., March, _et seq._, 1879.--_Lister_,
‘Phil. Trans.,’ 1690, p. 417.--_M’Clelland, J._, ‘Calcutta Journ. of
Nat. Hist.,’ vol. i, 1841, p. 366.--_M’Grigor, J._, “On the Guinea-worm”
(in his “Account of the Diseases of the 88th Regiment in Bombay”),
‘Edin. Med. and Surg. Journ.,’ vol. i, 1805, p. 284.--_Morehead, C._,
‘Calcutta Med. and Phys. Soc. Trans.,’ vol. vi, 1833, p. 418; also
noticed in ‘Edin. Med. and Surg. Journ.,’ vol. xliv, 1835.--_Idem_, part
ii, ‘Calcutta Med. and Phys. Soc. Trans.,’ vol. viii, 1836-42.--_Murray,
J._, “Guinea-worm a very Common Disease at Sattara” (in his Official
Report on the Hospital, &c.), ‘Bombay Med. and Phys. Soc. Trans.,’
No. 9, art. vi, p. 198, 1847.--_Oke, W. S._, “Case of Guinea-worm,”
‘Prov. Med. and Surg. Journ.,’ vol. vi, 1843.--_Oldfield_, “Case of
Dracunculus” (from Laird and Oldfield’s “Narrative of an Expedition into
the Interior of Africa”), ‘Dublin Journ.,’ vol. xii, 1838.--_Paton_,
“Cases of Guinea-worm,” ‘Edin. Med. and Surg. Journ.,’ vol. ii,
1806.--_Raddock_, “A Case of Guinea-worm,” ‘Indian Med. Gaz.,’ Oct.,
1877, p. 265.--_Scott, W._, “Remarks on the Dracunculus,” in a letter to
the Medical Board, Madras, ‘Edin. Med. and Surg. Journ.,’ vol. xvii,
1821.--_Leverance, C. E._, “History of a Case of Guinea-worm,” from
‘Amer. Med. Times,’ in the ‘Glasgow Med. Journ.,’ vol. ix, 1861-62, p.
377.--_Smyttan, G._, “On Dracunculus,” ‘Calcutta Med. and Phys. Soc.
Trans.,’ vol. i, 1825, p. 179.--_Stewart, L. W._, ‘Indian Ann. of Med.
Sci.,’ vol. vi, 1858, p. 88.--_Twining, W._, “Cases of Dracunculus,”
‘Calcutta Med. and Phys. Soc. Trans.,’ vol. vii, 1835.

[Illustration: FIG. 45.--Head of _Oxyuris vermicularis_. Highly
magnified. After Busk.]

_Oxyuris vermicularis_, Bremser.--Of all the parasites infesting the
human body this is the one concerning which the medical practitioner is
most frequently consulted, partly on account of its remarkable frequency
in children, and more particularly on account of the difficulty often
experienced in getting permanently rid of it. The _Oxyuris vermicularis_
is by no means confined to young persons, seeing that adults are
infested even to old age. It is familiarly known as the threadworm or
seatworm. The male measures about 1/6″, and the female from 1/3″ to 1/2″
in length. The female possesses a long capillary tail, which terminates
in a three-pointed end. The extremity is said to act as a kind of
holdfast. The tail of the male is obtusely pointed. In both sexes the
body presents a more or less fusiform shape, the anterior end being
narrowed to form a somewhat abruptly-truncated head, which is often
rendered very conspicuous by a bulging of the transparent integument
surrounding the mouth. This presents in profile the aspect of winged
appendages (fig. 45). The oral opening is tripapillated, leading into
a triangular œsophagus. The integument is transversely striated, and
of a silvery-white appearance. The spicule is simple, single, and very
minute. The eggs are oblong and unsymmetrical. They measure about 1/900″
from pole to pole, and 1/1400″ transversely.

[Illustration: FIG. 46.--Section of a female _Oxyuris vermicularis_,
magnified 220 diameters (after Busk); and also several free eggs
(original). _a_, With an imperfectly formed embryo; _b_, _c_, _d_, with
three tadpole-shaped embryos, magnified 450 diameters.]

Many years back (1863) I pointed out that the most advanced eggs whilst
still within the body of the pregnant female contained tadpole-shaped
embryos, and about the same time the fact was noticed by Claparède.
In his beautiful and scholarly memoir, ‘De la formation et de la
fécondation des œufs chez les vers Nématodes,’ he wrote concerning the
ova as follows:--“The egg, which exhibits the form of a very narrow
disk in the ovary, acquires the shape of an elongated ellipsoid in the
oviduct, and at the surface differentiates itself into a very thick
vitelline membrane. Then it forms a strong and resisting chorion, which
imparts to the egg an outline similar to that of a bridge’s span. It
has an oval figure flattened at one of its sides. This chorion is very
fragile; it frequently gives way under slight pressure from the thin
plate of glass which covers the object. It extends itself considerably
under the action of acetic acid, acquiring a size three or four times
greater than that of the egg. The constitution of this chorion is
perfectly identical in the eggs both before and after impregnation. It
is, nevertheless, easy at first sight to know whether or not we have
to deal with a fecundated egg. In the impregnated females the uteri
are filled with thousands of ova, each one of which encloses an embryo
already well formed. The ventral surface of the embryo and the tail are,
without exception, applied to the flattened side of the egg. The embryo
is very broad in the body, and occupies all the interior space. An
embryo such as Küchenmeister has represented under the form of a small
filiform worm folded on itself, and only occupying a very small part
of the cavity of the egg, is never to be seen. In the non-fecundated
females, on the other hand, the uteri are filled with eggs, which,
instead of the embryo, enclose a non-segmented yolk furnished with a
large germinal vesicle. This vesicle is not visible so long as the
eggs have the form of thin disks; it only shows itself when the eggs
begin to acquire an elliptical form in the oviduct. It is, however,
probable that this vesicle is the same which was originally visible in
the ovary.” The chorion itself is homogeneous, but in an allied species
(_Oxyuris spirotheca_) Gyoery and Claparède found that this egg-covering
consists of spirally-coiled bands resembling the tracheal spiral fibre
of an insect. Under suitable conditions the tadpole-shaped embryos
rapidly assume a vermiform character. The investigations of Leuckart
have shown that “one only needs to expose the eggs to the action of
the sun’s rays in a moistened paper envelope when, at the expiration
of five or six hours, the tadpole-shaped embryos will have already
become slender elongated worms.” According to Heller, the simplest way
to rear the vermiform stage of Oxyuris is to put a number of the eggs
in a glass tube filled up with saliva. The tube should then be placed
in the arm-pit, in which situation it can be carried about with little
inconvenience. In a few hours the transformations will commence and
go on continuously until the vermiform condition is attained. If, as
remarked in my ‘Lectures,’ it be asked whether the embryos which have
escaped into the bowel are capable of arriving at the vermiform stage,
the answer is in the affirmative; for, as Leuckart says, “the elongated
embryos are to be found not only in the fæces but also in the mucus of
the rectum above and around the anus.” Vix has also asserted that free
vermiform embryos are occasionally to be detected in the intestine of
the human bearer along with the eggs; this hatching within the lower
bowel, however, must, in my opinion, be regarded as exceptional. Heller
is of the same opinion. According to Leuckart, the escape of the embryos
from the eggs “ordinarily takes place under the action of the gastric
juice, also primarily in that condition when they have by some means or
other gained access to a new bearer.” Prof. Leuckart and three of his
pupils courageously infected themselves by swallowing the eggs, and had
the satisfaction of observing young Oxyurides in their stools fifteen
days afterwards.

From the united labors of Professors Zenker and Heller it is now
rendered certain that all the further changes necessary to bring the
larvæ to sexual maturity are accomplished within the small intestines of
the human bearer; and it is not necessary that a change of hosts should
occur at any time during the life of the parasite. Infection ordinarily
takes place by the accidental and direct conveyance of the eggs that are
lodged in the neighbourhood of the victim’s anus to the mouth. Since the
victim may accomplish this during sleep, it is not in all cases fair
to charge infected persons with uncleanliness. On the other hand, it
too often happens that due care in this respect has not been exercised,
and from such persons you may remove the eggs of Oxyurides from the
margins of the finger nails. One aristocratic person, who was infested
by myriads of these entozoa, confessed to me that in his extreme
distress, and consequent rage, he had freely bitten the live worms in
halves between his teeth. He had thus exposed himself to a terrible
revenge, since multitudes of the ova entering his mouth subsequently
found their way into the stomach and intestines. By whatever mode the
eggs are conveyed to the mouth their subsequent passage to the stomach
ensures their being hatched. In the duodenum and other divisions of
the small intestines, as Zenker and Heller have shown, the embryos
undergo transformation, casting their skins, and growing with great
rapidity. Probably not more than three weeks or a month is necessary
to complete their growth. Heller obtained mature worms from an infant
only five weeks old. Finally the worms are transferred to the cæcum,
which constitutes, so to speak, their headquarters. It is an error to
suppose that the lower bowel or rectum forms their especial habitat,
nevertheless the most approved manuals, vade mecums, and general
treatises have for a long time supported this erroneous view. The error
had been pointed out by Stricker in 1861.

[Illustration: FIG. 47.--Adult male _Oxyuris vermicularis_. Magnified.
After Küchenmeister.]

The symptoms produced by Oxyurides are occasionally very serious. In
the mildest cases they have a tendency to undermine the health. As
remarked in my ‘Entozoa,’ the unpleasant sensations chiefly develop
themselves in the evening and at night, consisting for the most part
of feelings of heat and irritation within and around the margin of
the anus. The symptoms may become extremely distressing and almost
intolerable, especially when the itching extends to the genito-urinary
passages, in consequence of the escape and migration of the parasites
about these parts. By-and-by various sympathetic phenomena, such as
restlessness, general nervousness, itchings at the nose, involuntary
twitchings, grinding of the teeth during sleep, chorea, convulsions, and
even epileptiform seizures, may supervene. At the age of puberty special
local disorders arise, the nature of which will be readily understood
when merely spoken of as the morbid phenomena of sexual irritation. In
the female the occurrence of pruritus and leucorrhœa is not uncommon,
accompanied or not, as the case may be, with hysteria in various forms.
There is usually general asthenia, with more or less emaciation. The
anæmia is sometimes remarkable, but in place of anorexia, which is,
however, an occasional symptom, one frequently finds a most voracious
appetite, especially in young people. Sometimes there are obscure
symptoms simulating those of local organic disease.

About the treatment of the disorder I have nothing to say here, further
than to urge the benefits of the preventive measure of cleanliness.
Like Zenker and Heller, I have obtained the eggs of oxyurides from
beneath the finger-nails of young people. In one lad all the nails had
been carefully bitten down to their roots, but from beneath a minute
projecting portion that was left on the right fourth-finger I procured
two eggs. Their demonstration under the microscope convinced both parent
and child of the necessity of frequently employing local and general
ablutions. Personal cleanliness is essential. In this connection an
able biologist has ventured to hazard a statement to the effect that
“probably any infected person who adopted the requisite precautions
against reinfection from himself or others would get well in a few
weeks without treatment by drugs.” Dr Ransom bases his belief on the
known facts of the life-history of this entozoon, as recorded more
especially by Leuckart. I regret that I cannot fully share Dr. Ransom’s
views, and still less should I think it right by my silence to seem to
endorse his statement to the effect “that every person who is shown
to be infested with those very common entozoa, _Oxyuris vermicularis_
and _Trichocephalus dispar_, is thereby demonstrated to have swallowed
minute portions of his own or another person’s fæces.” This is putting
the case too strongly. No doubt the eggs of oxyurides swallowed by
ourselves must have previously passed through some person’s rectum;
as such, either separately or mayhap collectively, in the body of the
maternal parasite. That does not, however, justify the statement, that
we “have swallowed” part of our own or of some other person’s excrement.
The eggs ought not to be regarded as constituent portions of the fæcal
matter. Perhaps Dr Ransom will say that the surfaces of these eggs,
being in contact with fæcal matter, must carry infinitesimal particles
on their surfaces, and it is to such that he refers. As, however, a
large proportion of the ova escape with their parents, whilst they are
still lodged within the maternal worm, it cannot be held that these
intra-uterine ova carry fæcal matter on their shells. Commonly the eggs
are swallowed in the separate, free, and dry state. In water they perish
quickly. The act of eating with unwashed hands is a fertile source of
infection, more especially if the meal be taken either in bed or in the
bedroom.

BIBLIOGRAPHY (No. 31).--_Alexander, J._, “On Vermination,” ‘Lancet,’
1833.--_Anderson, W._, “On Santonine, with especial reference to its
use in Roundworm and Threadworm,” ‘Brit. Med. Journ.,’ April, 1864,
p. 443; also in Braithwaite’s ‘Retrospect of Medicine,’ vol. xlix
(synopsis, p. 20), 1864.--_Barry, J. M._, “On the Origin of Intestinal
Worms, particularly the _Ascaris vermicularis_,” ‘Trans. Assoc. of Fell.
and Licent. of King’s and Queen’s Coll. of Phys. in Ireland,’ vol.
ii, 1878, p. 383.--_Bremser_, l. c., s. 79.--_Buckingham_, “Ascarides
causing Erotomania,” from ‘Bost. Journ., U.S.,’ in ‘Med. Gaz.,’
1857.--_Claparède, E._, “On the Formation of the Egg and Fertilisation
in the Nematoidea,” from the ‘Zeitsch. f. w. Zool.,’ translated by
Dallas in ‘Ann. Nat. Hist.,’ vol. i (third series), 1858.--_Idem_
(memoir quoted in the text above), Genève, 1859.--_Cobbold, T. S._,
‘Worms,’ Lect. xii-xv, 1872.--_Idem_, ‘Entozoa,’ p. 362.--_Idem_, ‘Brit.
Med. Journ.,’ Aug., 1873.--_Idem_, ‘Tapeworms and Threadworms,’ 2nd
edit., 1872.--_Idem_, ‘Lancet,’ 1866.--_Idem_, “On the Development and
Migrations of the Entozoa,” ‘Brit. Assoc. Rep.,’ 1864, p. 116.--_Date,
W._, ‘Lancet’ for Feb., 1872, p. 185.--_Davaine_, ‘Traité,’ l. c.,
2nd edit., p. 211, and ‘Synops.,’ p. 95.--_Dickinson_, “Case of
Epilepsy in Children relieved by the expulsion of Worms,” ‘Med. Times
and Gaz.,’ Jan., 1863.--_Dickson, R._, art. “Anthelmintics,” rep.
from the ‘Penny Cyclopædia,’ in Knight’s ‘Eng. Cyclop. Arts and Sci.
Div.,’ vol. i (column 365), London, 1859.--_Dreyfus_, “Irritation of
the Bladder from Ascarides,” from ‘Journ. de Med.,’ in ‘Lond. Med.
Gaz.,’ 1847.--_Elliotson, J._, “A Lecture on Worms,” ‘Lond. Med.
Gaz.,’ 1833.--_Idem_, “On Worms in the Intestinal Canal,” ‘Lancet,’
1831.--_Idem_, “On a Case of Threadworms,” ‘Lancet,’ 1831.--_Idem_, “On
Intestinal Worms,” ‘Lancet,’ 1830.--_Heller, A._, “Darmschmarotzer,”
in von Ziemssen’s ‘Handbuch,’ Bd. vii, s. 632 (see also Anglo-American
edit.), 1876.--_Küchenmeister_, l. c., Eng. edit., p. 356.--_Ransom_, in
Reynolds’ ‘Dictionary of Medicine.’--_Smith, A._ (and others), ‘Lancet,’
April 29th, 1865, p. 468.--_Stricker, W._, in ‘Virchow’s Archiv,’ xxi,
1861, s. 360.--_Tatham_, ‘Lancet,’ April, 1867, p. 457; see also p.
519.--_Vix, E._, ‘Ueber Entozoen,’ &c., Berlin, 1860; see also “On the
occurrence of Entozoa in the Insane, particularly with respect to the
_Oxyuris vermicularis_;” brief notice (‘Allg. Zeitsch. f. Psychiatrie’)
in Winslow’s ‘Journ. of Psycholog. Med.,’ vol. i, 2nd series, 1861,
p. 158.--_Zenker_, ‘Verhandl. d. phys. med. Soc.,’ H. ii, Erlangen,
1870, s. 20; and in ‘Tageblatt der deutschen Naturforscherversammlung
zu Dresden,’ 1868, s. 140 (also quoted freely by Leuckart, Davaine, and
Heller).

_Leptodera_ (_Anguillula_) _stercoralis_, Bavay.--In the summer of
1876 Dr Normand, of the French Marine, discovered this little entozoon
in the fæcal discharges of soldiers who had been sent home invalided
from Cochin-China. The patients in question were the victims of the
so-called Cochin-China diarrhœa or dysentery. This disorder is endemic
in character, and it had hitherto been regarded as consequent upon a
variety of causes other than parasitic. Dr Normand’s discovery, as
such, therefore takes equal rank with the analogous revelations made
by Bilharz, Harley, Leuckart, Zenker, Weber, Lewis, and Bancroft, in
respect of the particular helminthiases in man with which their names
are severally associated (Bilharzia disease, Endemic hæmaturia, Cestode
tuberculosis, Olulaniasis, Inter-tropical anæmia, Trichinosis, Lymphoid
affections, Helminthoma, and so forth), and also, if I may be permitted
to say so, with my own determinations in respect of a variety of
endemics affecting animals (cestode and nematode epizoöty in the horse,
the so-called grouse-disease, the pigeon-endemic due to lumbricoids,
&c.).

The _Leptodera stercoralis_ is a minute, smooth-bodied, simple,
rhabditiform nematode, measuring when full grown 1/25″ in length, with
an average breadth of 1/625 of an inch. The embryos at the time of their
extrusion measure only 1/250″ in length, but by the time at which a
rudimentary vesicle representing the uterus begins to form, the females
have already attained a length of about 1/83″. The males and females are
of nearly equal size. The transition from the embryonal state to the
higher larval conditions is accompanied by a change of skin, after which
the digestive and reproductive organs are gradually but rapidly formed
and completed. These changes have been minutely traced and recorded
by Professor Bavay, who also compares the entozoon with the genera
Rhabditis and Leptodera, in either of which genera the worm might be
placed. I have accordingly adopted the nomenclature suggested by Bavay.

[Illustration: FIG. 48.--_Leptodera intestinalis._ _a_, Adult female,
and separate figure showing a portion of the body with the ova _in
sitû_. The two outlined figures represent profile and front views of the
tail, respectively. _b_, _c_, Eggs with imperfectly formed embryos. _d_,
Larva. Highly magnified. After Bavay.]

As happens in all the kindred helminthiases that are known to be
dependent upon the presence of small worms, large numbers of Anguillules
are necessary to produce injurious effects upon the bearer. Thus, the
evacuations of the Cochin-China patients were found to contain such
multitudes of the worms that their numbers could only be adequately
estimated at so many hundreds of thousands passed in twenty-four hours.
Of course they varied in quantity, not only in different patients, but
in the same bearer, from day to day. They are to be found in every stage
of growth and development, from that of the intra-ovular embryo and
free embryonic state up to sexual maturity. They occupy all parts of
the intestinal canal, from the stomach downwards, being also found in
the pancreatic and biliary ducts, and likewise within the gall-bladder.
According to Bavay, five days suffice under favorable circumstances for
the complete maturation of the worm. This readily accounts for their
occasional extreme abundance.

I am indebted to the courtesy of Dr le Roy de Méricourt for the original
memoirs from which these brief abstracts are taken.

_Leptodera intestinalis_, Bavay.--This is a larger species, now and then
found associated with the above, and, according to Bavay, “in infinitely
less abundance.” This species was also discovered by Dr Normand, and
has been carefully described by Bavay. Possibly the worm may afford us
another curious instance of dimorphism. Be that as it may, it must be
provisionally regarded as a distinct form. As its occurrence is by no
means invariable, its rôle in relation to the Cochin-China diarrhœa
must, as Davaine has likewise remarked, be regarded as of secondary
importance. It is readily distinguished from _A. stercoralis_ both
in the adult and larval conditions. The full grown worm, although
comparatively narrow, is more than twice as long as its congener;
moreover, the larvæ, in place of possessing finely-pointed tails, have
blunt or truncated caudal extremities. Converting M. Bavay’s millimetric
measurements into fractions of the English inch, the average length of
the mature worms will be about 1/11″, whilst their breadth does not
exceed 1/757″ in diameter.

BIBLIOGRAPHY (No. 32).--_Bavay_, “Sur _l’Anguillule stercorale_,”
‘Comptes Rendus,’ Oct., 1876, p. 694, also in ‘Ann. Nat. Hist.,’ vol.
xviii, 4th series, p. 507, 1876, also noticed in the ‘Veterinarian,’
Jan., 1877, p. 19.--_Idem_, “Note sur _l’Anguille intestinale_,”
‘Archiv. de Méd. Nav.,’ July, 1877, p. 64, and in ‘Ann. Nat. Hist.,’
1877, vol. xix, 4th series, p. 350.--_Cobbold, T. S._, “Parasites of
Man,” in the ‘Midland Naturalist’ for January 1st, 1879.--_Davaine_,
‘Traité,’ l. c., 2nd edit., Supp., pp. 966-976, 1877.--_Laveran_,
in ‘Gaz. Hebd. de Med.,’ Jan., 1877, p. 42.--_Layet_ and _Le Roy de
Méricourt_, in ‘Dict. Encycl. des Sci. Med.,’ 1875.--_Libermann_, in
‘Gaz. des Hôp.,’ March, 1877, p. 237, and in ‘La France Méd.,’ 1877,
p. 165 (quoted by Davaine).--_Méricourt_ (see Layet).--_Normand,
A._, in ‘Comptes Rendus’ for July, 1876, p. 316, and Aug., 1876, p.
386.--_Idem_, in ‘Arch. de Méd. Navale,’ 1877, p. 35, and separately as
‘Mémoire sur la diarrhée dite de Cochinchine,’ Paris, 1877.--_Idem_,
“Du rôle étiologique de l’Anguillule dans la diarrhée de Cochinchine,”
in ‘Archives de Médecine Navale’ for September, 1878, pp. 214-224.

_Ascaris mystax_, Rudolphi.--This well-known helminth possesses aliform
appendages, one on either side of the head. It is of a medium size, the
male measuring 2-1/2″ and the female usually 3-1/2″ to 4″ in length.
Both as regards the size of the alæ and the length of the body it
varies in different hosts. Thus the variety infesting the dog has long
been regarded as a distinct species (_A. marginata_), partly from the
circumstance that the alæ are less conspicuous, and partly because the
individuals are often longer and thicker. I possess one specimen from
the dog measuring more than six inches in length. From like causes the
_Ascaris leptoptera_ and other varieties infesting the carnivora have
been regarded as distinct species, but the worm also varies in one and
the same host.

As remarked in my elementary treatise, the late Dr Bellingham, of St
Vincent’s Hospital, Dublin, published in the 13th vol. of the ‘Annals
of Natural History,’ an extended catalogue of Irish entozoa, and in
this list he recorded the existence of a new round worm in man. He
says of it:--“From the distinctness of the lateral membranes of the
head I have given it the name of _Ascaris alata_.” The catalogue was
constantly referred to by Dujardin, Diesing, and other systematists;
but some of the continental helminthologists do not appear to have had
access to Dr Bellingham’s more extended account of this parasite as
given in the first volume of the ‘Dublin Medical Press,’ No. 7, Feb.
20th, 1839. I am led to this inference from the doubt which some have
cast upon the very existence of the worm, although others, with more
candour, supposed that Bellingham had only mistaken the species. Thus,
Küchenmeister (‘Parasiten,’ s. 464, and in Lancaster’s edit., vol. ii,
p. 100) says:--“The _Ascaris alata_, found in the small intestines of
a man, is probably only a young individual of one of the long-known
nematoda, _if, indeed, it be a worm at all_!” (The italics are mine.)
This statement was reproduced by Hulme in his English edition of
Moquin-Tandon’s ‘Elements of Medical Zoology,’ p. 341; and the French
author himself evidently shared the doubt expressed by other people.
Dujardin (‘Helminthes,’ p. 156) admitted the species, as also did
Diesing (‘Systema Helminthum,’ p. 175), but the latter unluckily added
the following very significant suggestion:--“An _Ascaris lumbricoides_
capitis epidermide emphysematice inflata?”

Dr Leidy, of Philadelphia, admitted _A. alata_ among his _Entozoa
hominis_ without comment (‘Smithsonian Contrib.’ for April, 1853), but
Weinland, of Frankfort, in his list, prefixed a note of interrogation,
observing also that it had been “once” found in Ireland (‘Essay on
Tapeworms,’ p. 88). It is quite clear, therefore, that these authors did
not believe that the _Ascaris mystax_ was a human parasite. Those who
doubtfully accepted Bellingham’s _A. alata_ did so under the impression
that whatever it was, it could not be regarded as the common Ascaris of
the cat. In the new edition of Davaine’s ‘Traité,’ _A. alata_ is, to my
surprise, still retained as a separate species, and there is no mention
of the occurrence of _A. mystax_ in man. From what has recently been
written by several continental helminthologists (Leuckart, Heller, and
others), I rejoice to think that it is not necessary for me again to
advance the really superabounding proofs that Bellingham’s _A. alata_
was nothing more than _A. mystax_. It has at length been admitted
by almost all who are competent to form an opinion, that the memoir
originally communicated to the ‘Lancet,’ in 1863, and subsequently
introduced into the text of my introductory work, finally settled the
question of identity. It was through the donation of Dr Edwin Lankester
and Mr Scattergood that I was enabled at the time to announce the _third
instance_ of the occurrence of this parasite in man, and since that date
several other instances have been brought under public notice. Not less
than seven cases have now been noticed in which this little lumbricoid
of the cat and dog has been found in man. For one good human specimen I
am indebted to Dr Morton. In the above list I include Heller’s specimen,
and the one from Greenland sent by Steenstrup to Leuckart. According to
Hering’s observations this worm grows with remarkable rapidity. Worms
obtained from a puppy only six days old measured from 1/12″ to 1/6″ in
length. In a twelve-day-old puppy they reached nearly an inch in length,
and in a month the growth was up to four inches. Females only 1-1/2″ in
length already contained eggs, and males only 3/4″ long had acquired
their spicules. Three weeks therefore, would be amply sufficient for
the completion of sexual maturity within the feline or canine host. We
do not know, however, whether or not a temporary host is necessary for
the larvæ prior to their introduction into the cat or dog. Hering thinks
that a direct infection by the ova is sufficient; but he gives no proof
of the truth of this hypothesis. “Leuckart (as quoted by Heller, l.
c., s. 615) found numerous embryonal round worms in the stomach of a
cat, 1/62″ in length, and in addition all the intermediate stages of
growth up to the larger examples found in the small intestine. They
remain in the stomach until they have attained a length of from 1/18″ to
1/12″ and then pass into the small intestine. When they have attained a
length of nearly 1/8″ they cast their skins and change the tooth-like
boring apparatus for the three characteristic semicircular lips. These
observations on _Ascaris mystax_ (adds Heller) render it probable that
_A. lumbricoides_ is also introduced into the human alimentary canal
while still in the embryonal state or somewhat further advanced (und
wohl auch grösse).” The subject will be found more fully discussed in
my account of the large species further on. The cat’s worm possesses an
historical interest, not only in connection with Bellingham’s original
discovery, but also in respect of Nelson’s subsequent determinations as
to the precise mode of impregnation in nematodes. The subject is too
extended and too special to be dealt with here at any great length.

For several years after Nelson left the shores of England to spend a
too short life in New Zealand, the points discussed in his ‘Edinburgh
Thesis’ (and subsequently published in the ‘Philosophical Transactions’)
formed the subject-matter of numerous memoirs contributed to the leading
German scientific journals. Stated with brevity, it may be said that,
according to Nelson, the essential act of impregnation occurs when the
thimble-shaped spermatozoa of the male penetrate the unimpregnated or
ovarian ovum. This, he maintained, could and did take place at any part
of the surface of the unfertilised ovum, since the granular mass of
which it was composed, though well defined, did not, at this period,
possess a limiting--or true yolk--membrane. Professor Allen Thomson, in
a series of papers (some contributed in the German language), supported
Nelson’s views generally.

Amongst Nelson’s chief opponents was Meissner, who demonstrated that
the unimpregnated ova really possessed a delicate limiting membrane,
and that consequently the action of the spermatozoa was restricted to
that portion of the ovarian ovum which became exposed by rupture or
separation from the rachis. This opening he termed the micropyle. The
union of the sexual elements is quickly followed by a condensation of
the yolk-granules, and by the disappearance of the hitherto centrally
placed germinal vesicle. The ovum next assumes a distinctly oval
shape, the true yolk-membrane and the external chorional envelope now
becoming more and more differentiated, until the latter acquires a
regularly tuberculated surface. Co-ordinating with these changes the
granular yolk is seen transforming itself into a single large embryonal
cell; after a time this cell divides and subdivides by the ordinary
process of yolk-segmentation, until it is finally resolved into the
condition of a short, stout, vermiform embryo. The egg having assumed
its definitive oval shape, the intrachorional embryo remains coiled
within the shell, and does not make its escape until the egg has passed
from the body of the parent worm.

[Illustration: FIG. 49.--Germs and ova of _Ascaris mystax_. Nos. 1 to 3
magnified 330 diameters and Nos. 4 to 24 magnified 220 diameters. After
Nelson.]

Into the question of the mode of formation of the ovarian ova, and also
into that of the development of the spermatozoa, I do not enter. However
unwillingly, I must, in this matter, be contented to refer to Professor
Allen Thomson’s classical article ovum (quoted below), to Leuckart’s
elaborate analysis (l. c., Bd. ii, s. 76-92), and also, especially, to
the exhaustive memoir of Claparède, whose brilliant labors, like those
of Henry Nelson, were too early terminated by death. Shortly after
graduation Nelson suffered a virtually enforced banishment from his
native land.

BIBLIOGRAPHY (No. 33).--_Bellingham, O. B._, “On the Genus to which
the Worms known as Ascarides belong,” ‘Dublin Journ.,’ vol. xiv,
1839.--_Idem_, “Catalogue of Irish Entozoa,” ‘Ann. of Nat. Hist.,’
vols. xiii and xiv, 1843-44; and in the first part of Charlesworth’s
‘Mag. of Nat. Hist.,’ vol. iv, 1840. See also the address by Dr E.
D. Mapother on the “Lives and Writings of O’Ferrall and Bellingham,”
in the ‘Dubl. Journ. of Med. Sci.,’ Nov., 1877, p. 471 _et
seq._--_Bischoff_, ‘Widerlegung (u. s. w.),’ Giessen, 1853; quoted by
Claparède, l. c. _infra_, p. 9.--_Idem_, ‘Bestätigung (u. s. w.),’
Giessen, 1864.--_Idem_, “Ueber Ei-und Samenbildung und Befruchtung
bei _Ascaris mystax_,” Sieb. and Köll. ‘Zeitsch.,’ 1855, s. 377; also
in S. and K. ‘Zeitsch.,’ 1856.--_Bremser_, ‘Icones helminth.,’ p.
23, tab. iv.--_Claparède, E._, “Ueber Eibildung und Befruchtung bei
den Nematoden,” S. and K. ‘Zeitsch.,’ 1857, s. 106.--_Idem_, ‘De la
formation et de la fécondation des œufs chez les vers Nématodes,’
Genève, 1859. See also ‘Ann. of Nat. Hist.,’ vol. i, 3rd series,
1858.--_Cobbold_, in ‘Proceed. of the Zoological Soc. of London,’ Nov.,
1862.--_Idem_, ‘Brit. Assoc. Rep.,’ 1862.--_Idem_, “On the occurrence
of _Ascaris mystax_ in the Human Body,” with figures, ‘Lancet,’ Jan.,
1863; and in the ‘Dublin Med. Press,’ Feb., 1863.--_Idem_, ‘Entozoa,’
chap. xi, p. 316, 1864.--_Idem_, ‘Worms,’ pp. 72 and 112, 1872.--_Idem_,
in “Obituary Notice of Dr Henry Nelson,” ‘Med. Times and Gaz.,’ 1865
(?).--_Davaine_, ‘Traité,’ l. c., 1877.--_Diesing, C. M._, ‘Syst.
Helm.,’ vol. ii, p. 180, 1850.--_Dujardin_ (l. c., Bibl. No. 2), p.
162.--_Frœlich_, in ‘Naturf.,’ xxiv, s. 141 (_Asc. felis_).--_Funke,
O._, ‘Lehrbuch (u. s. w.),’ 1857, s. 1299.--_Gmelin_, ‘Syst. Nat.,’ p.
3031.--_Golze_, ‘Naturg.,’ l. c., s. 79.--_Gurlt_, ‘Path. Anat.,’ s.
366.--_Heller, A._, “Darmschmarotzer,” in Von Ziemssen’s ‘Handbuch,’ Bd.
vii, s. 361.--_Idem_, ‘Sitzungsb. d. Erlanger phys.-med. Soc.,’ 1872,
s. 73.--_Hering_, “Ueber das Vorkommen und die Entwicklung der _Ascaris
mystax_ bei jungen Hunden,” quoted by Leuckart from ‘Würtemb. Naturw.
Jahreshefte,’ 1873, s. 305-337.--_Kölliker_, in ‘Müller’s Archiv,’ 1843,
s. 68 _et seq._--_Leidy_, ‘Proc. Acad. Phil.,’ viii, p. 50.--_Leuckart_,
l. c., Bd. ii, s. 258.--_Meissner, G._, “Beobachtungen über das
Eindringen der Samenelemente in den Dotter,” S. and K. ‘Zeitsch.,’
1854, s. 208.--_Morton, T._, “Another Example of the Occurrence of
_A. mystax_, from a Child of fourteen months old,” in a letter to the
‘Lancet,’ March 11th, 1865, p. 278.--_Nelson, H._, “On the Reproduction
of _Ascaris mystax_,” ‘Proc. of the Royal Soc.,’ in ‘Philosoph. Trans.,’
and in ‘Med.-Chir. Rev.,’ 1051-52; also in ‘Froriep’s Tagsbericht.,’
1852, s. 205-207.--_Rudolphi_, ‘Synops.,’ p. 42, 1819.--_Schneider_,
“Ueber Bewegung an dem Samenkörperchen der Nematoden,” in ‘Monatsb. d.
Berliner Akad.,’ 1856, s. 192.--_Idem_, ‘Monographie der Nematoden,’
Erste Abth., s. 38, und Dritte Abth., s. 263 (“Entwicklungsgeschichte”),
1866.--_Siebold_, ‘Vergleichende Anatomie,’ 1848, s. 153, and in
Burnett’s edit., p. 125 _et seq._, 1854.--_Thomson, A._, art. “Ovum,” in
‘Todd’s Cyclop. of Anat. and Phys.,’ supp., 1859.--_Idem_, “Ueber die
Samenkörperchen, die Eier und die Befruchtung der _Ascaris mystax_,” S.
and K. ‘Zeitsch.,’ 1856, s. 425.--_Idem_, “Report of Glasgow Meeting”
(‘Brit. Assoc. Rep.’), 1855, p. 158.

_Ascaris maritima_, Leuckart.--This is a well-marked species. Judging
from the characters presented by the solitary, sexually-immature female
which supplied Leuckart with his only means of diagnosis, this worm
may be briefly described as a filariform nematode about 3/4″ in length
and about 1/25″ in breadth. Although there are no cephalic aliform
membranes, the cuticle immediately below the lips forms small and
distinct projections, one on either side of the head (‘Die Mensch.
Par.,’ Bd. ii, s. 877).

This entozoon was discovered by Dr Pfaff at Jacobshavn, near Godhavn,
West Greenland, in April, 1865. Two years later he sent the specimen
to Krabbe, who afterwards transmitted it to Leuckart. In the original
communication addressed to the Copenhagen helminthologist, Dr Pfaff
states that he procured the worm from amongst matters vomited by a
child, and he incidentally observes that he had hitherto encountered
only _Bothriocephalus cordatus_ and _Oxyuris vermicularis_ amongst
Greenlanders. As to the source of infection, Prof. Leuckart not
unnaturally refers to the similar conditions of existence shared by the
human and carnivorous inhabitants of that country. It is well known
that bears, polar-bears, seals, and walruses are largely infested by
nematodes (_Asc. transfuga_, _A. osculata_, _Ophiostoma dispar_, &c.),
but these various species are quite distinct from Dr Pfaff’s little
“spulwurm.”

_Ascaris lumbricoides_, Linneus.--This common parasite was for a long
while regarded as identical with the great lumbricoid of the horse,
but the question has been finally settled by Schneider, who has shown
that the human worm, although identical with Dujardin’s _Ascaris
suilla_ of the hog, is nevertheless quite distinct from the _Ascaris
megalocephala_ of solipeds. The large lumbricoid occasionally found in
the ox belongs to the human worm. Our large human helminth resembles
the common earth-worm in general appearance only. The males usually
measure from four to six inches in length, and the females from ten to
fourteen inches. Some have been reported up to seventeen or eighteen
inches in length. The body is smooth, fusiform, and elastic, and marked
by numerous fine transverse rings. It is attenuated towards either
extremity, the anterior end terminating in a prominently three-lobed
mouth The tail is bluntly pointed. The female is much shorter than the
male, having a diameter of nearly a quarter of an inch. The male is
supplied with a double spiculum, its tail being always more or less
curved towards the central surface. The female reproductive orifice
is situated above the centre of the body. According to Schneider, the
tail supports from 138 to 150 caudal papillæ, that is, from 69 to 75 on
either side of the median line. Below the anus the papillæ are regularly
arranged in pairs, seven in number, the two uppermost pairs being
double.

Notwithstanding the advantage which the size of this entozoon affords
us in the matter of observation and experiment, we are yet ignorant
as to the precise mode in which the young gain access to the human
body. From what has been said respecting the quick growth of _Ascaris
mystax_ in the dog, and from what has been observed respecting the
rapid growth of the so-called _A. suilla_ in the hog, we know that the
worm requires but a short time to pass from the larval to the sexual
state. The view of Hering, Mosler, Davaine, and others, who suppose
that these worms are reared in a direct manner by swallowing the ova,
is, as Leuckart observed, not yet proved. We are not in full possession
of the facts of larval development. It is true that Professor Heller’s
interesting “find” has shown that when these worms first gain access to
the human body their size is quite insignificant. At the post mortem
of an imbecile, Heller discovered eighteen young worms, varying in
size from about 1/9″ to 1/2″ in length (2·75 to 13 mm.). The sexes
were indistinguishable. As a set-off against this, Leuckart’s repeated
attempts to rear _Ascaris lumbricoides_ and _A. mystax_ by means of
direct feeding-experiments with the eggs all failed. Thus, we are yet
left in doubt as to the destiny of the larvæ during the period which
elapses between the time of their escape from the egg and the time of
their entry into the human body. So important is the question as to
the mode of origination, growth, and subsequent development of the
larvæ, that it may be well to trace, however briefly, what steps have
been taken to clear up the matter. Leuckart obtained his negative
results by the administration of ripe ova to dogs, rabbits, swine, and
mice. The eggs of _Ascaris lumbricoides_ have been kept alive by Dr
Davaine for a period of more than five years. I have myself watched the
development of their contents in fresh water through all the stages of
yolk segmentation up to the stage of an imperfectly-organised, coiled,
intra-chorional embryo, and have kept them in the latter condition
for a period of three months. According to Davaine (‘Comptes Rendus,’
1858, p. 1217), the fully-developed embryo is cylindrical, its length
being, 1/100th of an inch. The mouth is not furnished with the three
characteristic papillæ of the genus, and the tail terminates suddenly in
a point. Davaine administered some of his five-year-old embryos to rats,
and had the satisfaction of finding a few of these eggs in the rodent’s
fæces, with their embryos still living, but striving to emerge. He also
gave eggs to a cow, and introduced others into the stomachs of dogs in
small linen-covered flasks. As a general result it may be said that the
embryos escaped from their shells. Those eggs, however, in which the
yolk-segmentation had not arrived at the early embryonal stage remained
unaffected. According to Heller, the embryo of _A. lumbricoides_ casts
its first skin while still within the egg, and “a subsequent ecdysis
probably completes its definitive form” (l. c., s. 615). So far back
as 1853 Verloren reared coiled intra-chorional embryos in the eggs of
_Ascaris marginata_ within a period of fifteen days in distilled water.
I also reared the embryos of this species in fresh water, and kept them
alive for a period of nearly a year and a half, at the expiration of
which time, and during the warm weather, some few of them succeeded in
making their escape. According to Davaine, the eggs of many nematode
species will readily retain their vitality though long exposed to
dryness, but their yolk-contents will not go on developing during this
period of exposure. As regards _A. mystax_, however, Heller remarks that
whilst “the eggs have a great power of resisting external influences,
their development is not arrested in spirits of wine, chromic acid, or
oil of turpentine” (l. c., s. 631). In the case of _Ascaris tetraptera_
of the mouse, embryonic formation goes on in spite of the absence of
external moisture. Davaine has noticed the same thing in the oxyurides
of rodents. Dryness does not even destroy the eggs of _A. lumbricoides_
and _Trichocephalus dispar_. It would seem, in short, that the eggs of
nematodes which normally take up their residence in cats, dogs, and in
the carnivora which reside in arid regions, will develop embryos in
the egg without external moisture. As before remarked, Davaine thinks
it is not necessary that these nematode embryos should pass through
any intermediary bearer, and he believes that they are often directly
transferred to the stomach of their “hosts” whilst adhering in the form
of an impalpable dust to the coats of their bearers, whence they are
detached by the animal’s frequent habit of licking the fur. Davaine’s
view has received some support from the observations and experiments
of Unterberger with the eggs of _Ascaris maculosa_. This observer
administered eggs of the worm to doves (whose fæces were free of eggs),
and seventeen days after found ova in the fæces.

With the eggs of the _Ascaris megalocephala_ of the horse I performed
numerous experiments. I reared the embryos in simple fresh water, and
found them during warm weather escaping before the expiration of five
months. I also succeeded in rearing these larvæ in pond mud, noticing,
at the same time, that after their escape from the shell they grew more
or less rapidly up to a certain point, after which they ceased growing.
The addition of horses’ dung to soft wet mud in one case, and of cows’
dung in another, neither appeared to advance nor retard the process
of embryonal formation, so long as the embryos were enclosed in their
shells. On the other hand, when I reared embryos in simple horse-dung
purposely kept moist, they attained a higher degree of organisation than
did those in wet mud or water. Having watched hundreds of these larvæ
under varying conditions, I came to the conclusion that, after escape
from the egg, their activity, growth, and strength was most marked when
they occupied media which happened to be impure. Davaine experimented
on cows, and Leuckart also experimented on horses, with the eggs of
this worm without success. Leuckart also failed to rear the larvæ in
intermediary hosts. Some eggs passed through the water-palmer unaltered.

These results, so far as they go, seem to be borne out by facts of a
professional order. Thus, an instance has been brought under my notice
where a considerable number of peasants and their children, dwelling
in a parish in Yorkshire, were infested with this worm. There was,
in short, a local endemic helminthiasis. Through the parish runs a
stream which supplies the cottagers with all the water they employ
for domestic purposes (washing, drinking, and so forth). Some of the
peasants living by the side of the stream keep pigs, and the sewage
from this source has been allowed to pass into the stream itself. Now,
if Schneider’s determination as to the identity of the lumbricoid of
man and the pig is correct (which I do not doubt), the explanation of
the cause of the endemic becomes a very simple matter. But it does not
explain all that we desire to know about the young worms. Either the
freed embryos before they enter the human bearer accomplish further
changes of form and growth in the sewage or impure water; or, what is
far less probable, they pass into the bodies of intermediary hosts (such
as insect-larvæ, Gammari, Entomostraca, &c.) to undergo the necessary
changes. Practically, no doubt, it comes to the same thing in the end.
Even if we suppose that the _Ascaris suilla_ and _A. lumbricoides_ are
not identical species, still it is evident that any person discharging
the eggs of lumbricoids in the vicinity of open waters becomes, by that
fact, a source and centre of infection. To ensure an endemic it is
probably only further necessary that the human inhabitants should employ
the contaminated water for domestic purposes. But time and an increase
of temperature must be allowed for the bringing about of those known
and unknown larval changes that alike form the necessary antecedents
of infection. In this connection I will only add, that if the present
position of the question be such as I have here represented it to be, we
see that Mosler was not far wrong when he suggested that “contamination
of the drinking water with the eggs out of privies is to be blamed” as
a source of infection. According to Heller, from whom I quote, Mosler
actually demonstrated the presence of the eggs in water thus exposed. In
like manner it becomes obvious that Davaine’s practical remark (although
it was based on the assumption of a direct infection by the eggs), that
filtration will probably be sufficient to prevent infection, loses
nothing of its hygienic value.

The foregoing observations naturally lead one to the question of
frequency and distribution. Davaine holds that the comparative
infrequency of this parasite in Paris is due to the free use of the
filter. In London, though not uncommon, the worm rarely occurs in great
numbers in one bearer. Those cases in our hospitals, where considerable
numbers have been present, have usually come up from suburban or country
places. Heller states that these worms were found in 9·1 per cent. of
post mortems conducted at Dresden, in 12 per cent. at Erlangen, and in
17 per cent. at Kiel. He quotes Huss as stating that no one is free
from this worm in Finland. The prevalence of large round worms in warm
countries generally is well known. Throughout India and the East they
are extremely abundant, and the same may be said of the West Indies,
Brazil, and the adjacent territories. Professor Dyce and others have
remarked on the extreme prevalence of lumbrici in the Mauritius, but
they are comparatively rare along the sea border. In all situations
where there is an abundant fresh-water supply these parasites are
particularly common, as in the lowlands of Holland and the lake
districts of Sweden. The abundance of water is certainly not alone
sufficient to explain the frequency of the parasite, seeing that the
most important factor is that which rests upon the uncivilised habits
of the rural population. What, therefore, it may be asked, can be the
cause of immunity enjoyed by Icelanders in this respect? The answer is
not apparent; nevertheless Krabbe and Finsen have testified to the fact
that Iceland is the only country that is entirely free from _Ascaris
lumbricoides_.

As remarked in my previous work the number of worms present in any human
bearer is usually small, varying commonly from one to six or eight.
Cases in which scores or hundreds have existed are comparatively rare.
Küchenmeister mentions the case of one child who passed 103 examples,
and of another child that harbored from 300 to 400 worms. Dr Gilli, of
Turin, gives a case where 510 were passed by a child, and Cruveilhier
estimated that over 1000 existed in an idiot girl, whose intestines he
found crammed with them. A remarkable case has also been communicated
to me by Dr Mackeith, of Sandhurst, Kent, who, by means of santonine,
expelled from a little girl, five and a half years of age, 300 lumbrici;
and I am likewise indebted to Dr Cooper Rose for notes of a case in
which about thirty lumbrici were expelled, chiefly in consequence of the
employment of this drug. The most interesting fact, however, in this
case was that the child was only fifteen months old. In this case the
symptoms were severe.

The proper habitat of the lumbricus is the upper and middle part of the
small intestine. From this situation it often wanders into the stomach,
and frequently gains access to the outer world, not only by the natural
passages of the mouth, nostrils, and anus, but also, occasionally, in
a more direct way, by perforating the intestinal and abdominal walls.
Many cases are on record where lumbrici have passed into the abdominal
cavity. In other instances they have lodged themselves within the
abdominal viscera and pulmonary organs. When they find their way into
the parietes of the abdomen and adjacent parts, they usually give rise
to the formation of abscesses requiring surgical interference.

As regards the symptoms produced by lumbrici, these vary according to
the situation they happen to occupy. The symptoms are also modified
by age and temperament. In the stomach and intestines they give rise
to colic and shooting pains about the abdomen, followed generally
by dyspepsia, nasal itching, nausea, vomiting, and even diarrhœa.
Occasionally death supervenes suddenly. A singular case of this kind
(the particulars of which I only gathered from a local newspaper)
occurred in a boy, thirteen years of age, at the County Gaol at
Hertford, in 1873. From Dr Evans’s statement, made at the coroner’s
inquest, the sole cause of death appeared to be due to pressure on
the windpipe by a worm lodged in the gullet. Sometimes there is
cerebral disturbance, attended with general restlessness and convulsive
twitchings during sleep. Thus, Dr Woodman has recorded a serious case
of convulsions arising from lumbricoid worms, in which, however, a cure
was effected by expulsion of the worms. An anonymous writer in the
‘Medical Gazette’ records a case of epilepsy from this cause, whilst
another writer in the same journal (1839) mentions an instance where two
lumbrici and one tapeworm were associated in the production of similar
phenomena. But a much more striking case is also given (anonymously)
in the ‘Gazette’ for 1874 (p. 415), where a single lumbricus caused
the bearer to be a lunatic for eight years. The victim suffered from
cataleptic fits, which lasted for two or three weeks at a time. M.
Petrequin, in his ‘Traité Pratique,’ records two cases of amaurosis in
young girls produced by lumbrici. A fatal case is recorded by Petrenz,
where 200 worms produced enteritis, and another fatal case is given
by Roger from perforation (1848). Cases of perforation are also given
by Young, by Blair (1861), by Mondière (1839), by Buchner (1851), by
Sheppard (1861), and by Luschka (1854), the worms in this last-mentioned
case occupying the cavity of the pleura. Cases of severe irritation
affecting the genito-urinary organs are given by Dreyfus, Buckingham,
and others; and one or two instances are reported where these worms have
been discharged from several parts of the body (Neilson, 1833). I may
add that the third fasciculus of a work illustrating the collection of
morbid anatomy in the Army Medical Museum at Chatham gives a case of
lumbrici occupying the biliary ducts and gall-bladder. I find, moreover,
two additional cases of perforation of the small intestine, one of which
appeared in the ‘London Medical Gazette’ (1827) and the other in the
‘Lancet’ (1836).

During the Franco-German war Dr Reginald Pierson, as he afterwards
informed me, removed a lumbricus from an abscess formed in the abdominal
parietes of a soldier. But amongst the most curious cases (illustrating
the wandering habits of these parasites) are those severally described
by Barwell (1857), Williams, Prichard, and the Messrs Stockbridge. In
Barwell’s case an Ascaris was expelled from a child who had swallowed
the brass “eye” of a lady’s dress. Through the circular loop of
this eye, used as a toy, the Ascaris had partly thrust its body,
and becoming thus strangulated, it probably perished before it was
evacuated. In Prichard’s case (1859) one or two lumbrici had similarly
trapped themselves in the eyes of buttons swallowed by the patient,
and one worm, not contented with a single strangulation, had succeeded
in passing its body through two buttons. In 1842 Mr T. G. Stockbridge
gave a similar case, in which he, not inaptly, spoke of these “hooks
and eyes” as constituting a new remedy or “worm-trap” for lumbricus,
and singularly enough, a namesake (W. Stockbridge), in the succeeding
year, also recorded a like instance of the “mechanical expulsion of
worms” by metallic buttons. Again, a third correspondent in the ‘Boston
Journal,’ under the initials A. M., spoke of an open-topped thimble
as constituting another new “worm-trap,” whilst he gave a case of
lumbrici penetrating “metallic suspensor buttons.” There is also the
case reported by Williams, who, at a meeting of the Boston Society for
Medical Improvement, exhibited “a lumbricus with a dress-hook attached”
(1857). Lastly, another lumbricus, trapped in the same way, may be seen
in the Museum of the Royal College of Surgeons at Edinburgh.

Owing to the presence of a peculiar irritating vapour which is given
out by these lumbricoids, particularly when fresh, several observers
have experienced curious symptoms. Thus, Miram on two occasions, when
examining _A. megalocephala_, was attacked with sneezing, excessive
secretion of tears, with swelling of the puncta lacrymalia, and Huber
also experienced a troublesome itching of the hands and neck after
examining specimens of _A. lumbricoides_. In like manner I have myself
had watery suffusion of the eyes (when collecting the perivisceral
fluid for Marcet’s analyses: see Bibliog.), and Bastian has given a
detailed account of the serious effects which the poison produced upon
him. In Bastian’s case even spirit specimens produced irritation.
The attacks of catarrh and asthma were so persistent and severe that
they lasted for six weeks at a time. So sensitive was Bastian to the
lumbricoid-miasm that he could not even put on a coat that he had worn
during his investigations without experiencing fresh attacks of sneezing
and other catarrhal symptoms. The attacks became periodical, occurring
between five and six in the morning, being accompanied by dyspnœa and a
distressing spasmodic cough. Bastian, in short, was quite a martyr in
the cause of nematode anatomy.

BIBLIOGRAPHY (No. 34).--_Abousson, L._, “On the Presence of Worms
(lumbrici) in the Air-passages,” from ‘Arch. Gén. de Méd.,’ in
‘Med.-Chir. Rev.,’ 1836.--(Anonymous), _A. M._, “Another New
Worm-trap--an open-topped Thimble in the Nostril (also notice of
metallic suspender buttons penetrated by Lumbrici),” ‘Bost. Med. and
Surg. Journ.,’ vol. xxvii, p. 121, 1842-43; see also T. G. and W.
Stockbridge.--(Anon.), “Lumbrici expelled by Bismuth,” ‘Bost. M. and
S. Journ.’ (from ‘Gaz. des Hôp.,’ ‘Journ. des Connaiss. Méd.,’ and
‘Boletin del Inst.-Med.-Valenc.’), 1859.--(Anon.), “Case of one Tapeworm
and two Lumbrici causing Epilepsy,” from ‘Bull. du Midi’ and ‘Gaz.
Méd.,’ 1839.--(Anon.), “Case of Perforation of the Ileum by Ascarides,”
from ‘Hufl. and Ossan’s Journ.,’ in the ‘Lancet,’ 1836.--(Anon.),
“Case of Lumbrici in the Biliary the Ducts and Gall-bladder,” note
and fig. in third fasc., illust. the Coll. of Morb. Anat. in the Army
Med. Mus. at Chatham, 1838.--(Anon.), “A Lumbricus causing Catalepsy,
with Fits lasting two or three weeks; Cure by Vomiting,” ‘Lond. Med.
Gaz.,’ 1847, p. 415.--_Archer, E._, “On a Case of _A. lumbricoides_
producing alarming symptoms,” ‘Lancet,’ 1857.--_Barwell_, “Case of
Ascaris expelled by the swallowing of a foreign body,” ‘Lancet,’
1857.--_Bastian, H. C._, “On the Anatomy and Physiology of the
Nematoids, Parasitic and Free,” ‘Phil. Trans.,’ 1866, p. 545; for the
account of his poison-symptoms, see _footnote_, p. 583.--_Batterbury,
R. L._, “Jaundice due to the presence of Lumbrici,” ‘British Med.
Journ.,’ Nov., 1878, p. 721.--_Bigelow, H._, “Worm in an Abscess,”
‘Bost. Med. and Surg. Journ.,’ vol. xxxiii, p. 486, 1836.--_Blatchley,
C. C._, “Two Cases of _A. lumbricoides_, attended with Abscesses,
followed by large purulent discharges, and Worms therein,” ‘New York
Med. and Phys. Journ.,’ vol. i, new series, p. 209, 1829.--_Bonfils,
E._, “Lesions and Path. Phenomena caused by Lumbrici in the Biliary
Ducts,” from ‘Arch. Gén.,’ in ‘Brit. and For. Med.-Chir. Rev.,’ 1858,
and in ‘Amer. Journ. of Med. Sci.,’ vol. xxxvii, 1859.--_Bradford,
J. T._, “Singular Case of Worms (Lumbrici),” ‘Bost. Med. and Surg.
Journ.,’ vol. xxviii, 1843.--_Brigham, A._, “Worms in the Bladder
simulating ‘Stone,’” ‘Amer. Journ. Med. Sci.,’ 1837; ‘Med.-Chir. Rev.,’
1837; ‘Quart. Journ. Calcutta Med. and Phys. Soc.,’ vol. ii, p. 132,
1838.--_Buchner_, “On the Perforation of the Intestinal Canal by Worms
(with ref. to two cases),” from ‘Med. Zeitung,’ 1850, in ‘Med.-Chir.
Rev.,’ 1851.--_Calderwood_, “Treatment,” ‘Brit. Med. Journ.,’ Jan.
30, 1875.--_Chapman, N._, “Case of 68 Ascarides causing Pulmonary
Disease,” in his ‘Dis. of the Thoracic and Abd. Viscera,’ p. 263,
and in ‘Med.-Chir. Rev.,’ 1845.--_Chiaje, Delle-_, in ‘Rend. dell’
Accad. di Napoli,’ 1846 (“Anat.,” p. 403).--_Church, J._, “On _A.
lumbricoides_,” ‘Mem. Med. Soc. Lond.,’ vol. ii, 1789.--_Claparède_
(l. c., Bibl. No. 33, for development).--_Clark, P._, “Discharge of
a Lumbricus through the Male Urethra,” ‘New York Journ. Med.,’ 1844,
rep. in ‘Lancet,’ 1844, and in ‘Edin. M. and S. Journ.,’ vol. lxiv,
1845.--_Cloquet_, ‘Anat. des vers Intest.,’ 1824.--_Cobbold_, “On Sewage
and Parasites, especially in relation to the Dispersion and Vitality
of the Germs of Entozoa,” ‘Med. Times and Gaz.,’ Feb. 25, 1871, p.
215.--_Idem_, ‘Entoz.,’ p. 302-315.--_Idem_, ‘Worms,’ lect. xvi, p.
3.--_Idem_, art. “Ascaridæ,” in ‘Maunder’s Treasury,’ 1862.--_Colvan,
J._, “Case in which Eleven Round Worms of the species _A. lumbricoides_
were removed by Anthelmintics,” ‘Dubl. Med. Press,’ vol. xxvi, p. 211,
1851.--_Cutler, J. H._, “Death by Worms (a large Lumbricus being found
in the Wind-pipe),” ‘Bost. Med. and Surg. Journ.,’ vol. lxvi, p. 392,
1862.--_Czermak_, in ‘Sitz. d. k. Akad. d. Wissensch.,’ 1852 (“Anat.,”
s. 755).--_Davaine_, in his ‘Traité,’ l. c., 2nd edit., syn. xcvii,
and p. 122-235 (with details of forty-five cases); see also his memoir
“On the Development and Propagation of the _Trichoceph. dispar_ and
_A. lumbricoides_,” from ‘Comptes Rendus,’ in ‘Ann. Nat. Hist.,’ vol.
ii, 3rd series, 1858; also in the ‘Journ. of Pract. Med. and Surg.,’
Eng. edit., vol. i, 1858, and in the ‘Veterinarian,’ vol. xxxii, p.
700, 1859, from ‘Proc. of Acad. des Sci.,’ in ‘Bost. M. and S. Journ.,’
vol. lix, p. 157, 1858-59.--_Idem_, art. “Entozoaires,” in ‘Dict. de
Méd. et Chir. prat.’--_David, J. B._, “Cases of Perforation of the
Intestines by Worms,” from ‘Gaz. Méd. de Paris,’ in ‘Dubl. Med. Press,’
1840, p. 223.--_Diesing_, ‘Syst. Helm.,’ ii, p. 166; and in ‘Revis der
Nemat.,’ l. c., s. 660.--_Douglas, J._, “Worms (Lumbrici) evacuated at
an Ulcer of the Groin,” ‘Med. Ess. and Obs.,’ vol. i, 2nd edit. (vol.
i, 5th edit., p. 179), p. 222, 1737.--_Dowler, B._, “Case of Worms in
the Urinary Bladder,” from ‘New Orl. M. and S. Journ.,’ in ‘New York
Journ. Med.,’ new series, vol. xiv, 1855.--_Dubini_, ‘Entozoografia
umana’ (“Anat.,” p. 148).--_Dupuytren_, “Lumbricus passed by the
Urethra,” from “Clin. Lect.,” in ‘Lond. Med. and Surg. Journ.,’ 1846,
p. 14.--_Dyce, R._, “On Lumbrici and the Causes of their Prevalence
in the Mauritius,” ‘Lond. Med. Gaz.,’ 1834.--_Evans, T._, “Lumbricus
causing Death,” rep. of coroner’s inquest in the ‘Herts Advertiser and
St Alban’s Times’ for Feb. 8, 1873.--_Gervais_ (and _Van Beneden_),
‘Zool. Med.,’ ii, p. 118.--_Gilli_, “Account of a Case in which 510
Worms (Lumbrici) were voided by a Child,” from ‘Giorn. d. Scienze
Med. di Torino,’ in ‘Med.-Chir. Rev.,’ 1843.--_Goopta, G. D. D._, “On
Suicide and Lumbrici,” ‘Ind. Med. Gaz.,’ July, 1874, and ‘Lond. Med.
Rec.,’ Aug., 1874, p. 502.--_Heller, A._, “Darmschmarotzer,” in Von
Ziemssen’s ‘Handb.,’ s. 612-631.--_Holland, G. C._, “A peculiar Case
of Nervous Disease or Derangement of the Nervous System (associated
with _A. lumbricoides_),” ‘Edin. M. and S. Journ.,’ vol. lxiii,
1845.--_Howall_, “Abscess of the Groin, with discharge of Lumbrici,”
‘Lond. Med. Gaz.,’ 1845, and ‘Edin. M. and S. Journ.,’ 1846, p.
241.--_Johnson, W. G._, “Case of forty Lumbrici in a Boy who died with
Traumatic Tetanus,” “Rep. of South Mid. Br. of Brit. Med. Assoc.,” in
‘Brit. Med. Journ.,’ 1858.--_Kell_, “Perforation of the Intestines by
a Worm,” ‘Lond. Med. Gaz.,’ 1828.--_Kilgour, T._, “Case in which Worms
in the Nose, productive of alarming Symptoms, were removed by the Use
of Tobacco,” ‘Med. Comment.,’ vol. viii, 1783.--_Kirkland_, “Case of
Lumbricus in an Abscess of the Liver,” rep. in his book, entitled ‘An
Enquiry,’ vol. ii, p. 186 (quoted by Richter and Davaine), London,
1786.--_Küchenmeister_, ‘Manual,’ Eng. edit., p. 410-427.--_Leidy,
J._, ‘Proc. Acad. Phil.,’ 1856, p. 50.--_Lente, F. D._, “Lumbricus
in the Stomach causing Dyspnœa,” in his “Rep. of Cases occurring
in the New York Hosp.,” in ‘New York Journ. of Med.,’ vol. v, new
series, p. 167, 1850.--_Lettsom_, “Case of Lumbricus evacuated from an
Abdominal Abscess,” ‘Trans. Med. Soc. Lond.,’ and ‘Lond. Med. Repos.,’
1817.--_Leuckart_, l. c., s. 152-258.--_Lieberkühn_, in ‘Miller’s
Arch.’ (“Anat. of _A. suilla_”), 1855, s. 331.--_Luschka_, “Case of
Lumbrici within the Pleura,” from ‘Virch. Arch.,’ in ‘Med.-Chir. Rev.,’
1854.--_Lowne, B. T._, “The Anatomy of the Round Worm,” ‘Trans. Roy.
Micr. Soc.,’ 1871, p. 55.--_Maesson_, “On a Worm found in the Bubo of
a Woman 36 years of age;” see ‘Entozoa and Parasites, being a ref. to
numerous papers;’ from “Valentin’s Repertorium,” in ‘Month. Journ. of
Med. Sci.,’ vol. ii, p. 559, 1842; also in ‘Micr. Journ. and Struct.
Rec.,’ p. 85, 1842.--_Marcet, W._, “Chemical Exam. of the Fluid from
the Peritoneal Cavity of _A. megalocephala_,” ‘Proc. Roy. Soc.,’ 1862,
No. 72, p. 69.--_Martin, D. T._, “Large number of Worms (140 examples
of _A. lumbricoides_) discharged from a Child five years old,” rep.
from the “Stethoscope,” in ‘Bost. Med. and Surg. Journ.,’ vol. xliv, p.
301, 1851.--_Mattei, R._, “On a Case of two Lumbricoid Worms, which had
penetrated during life into the liver, and were demonstrated by Prof.
G. Pelizzari to his pupils in the Sch. of Path. Anat. of Florence,”
from ‘Gaz. Med. Ital. Toscana,’ in ‘Dubl. Quart. Journ.,’ vol. xxiv,
1857.--_Michel_, “Case of Epilepsy in a Girl ten years of age, caused
by Lumbrici,” from ‘Journ. des Connaiss. Méd.,’ in ‘Amer. Journ. of
Med. Sci.,’ vol. vi, p. 451, 1843.--_M’Laggan, J._, “Gangrenous Sore
from a large Worm in the Parietes of the Abdomen,” ‘Med. Comment.,’
vol. ii, 1774, p. 80.--_Molin_, in ‘Sitzungsb. d. k. Akad.,’ 1859,
s. 23.--_Mondière_, “On Perforation by Worms (three cases),” from
‘L’Expérience,’ in ‘Med.-Chir. Rev.,’ 1839.--_Moore, E. D._, “Example
of _A. lumbr._ ejected by the Mouth,” ‘Prov. Med. and Surg. Journ.,’
1852.--_Morgan, J._, “Case of Perforation of the Stomach, probably by
a (Lumbricus) Worm,” ‘Lancet,’ 1836.--_Morland, W. W._, “Ejection of
numerous Lumbrici from the Mouth, impaction of the small intestine
with Lumbrici, (of which 365 were removed post mortem),” ‘Bost. M. and
S. Journ.,’ vol. lvi, 1857.--_Idem_., an “_A. lumbr._ of unusual size
(over 17 inches long),” ‘Rep. of Bost. Soc. for Improv.,’ in ‘Bost.
M. and S. Journ.,’ vol. lviii, p. 62, 1858.--_Neilson_, “Discharge of
Worms from various parts of the Body,” ‘Med.-Chir. Rev.,’ and ‘Lond.
Med. Gaz.,’ 1833.--_Omond, R._, “Case of Lumbricus attended with
Hæmoptysis,” ‘Edin. Med. Journ.,’ 1856.--_Owen, R._, art. “Entozoa,” l.
c.--_Padley, G._, “Jaundice and Lumbrici,” ‘British Med. Journ.,’ Dec.
14, 1878, p. 877.--_Petrenz_, “Case of fatal Enteritis produced by (200)
Lumbrici,” from ‘Clarus and Radius’ Beitr. zur Pract. Heilk.,’ in ‘Dubl.
Journ.,’ vol. xi, 1837; also in ‘Lond. Med. Gaz.,’ 1837.--_Playfair_,
“Case of Lumbricus (69 specimens) cured by the Mudar,” ‘Calc. Med.
and Phys. Soc. Trans.,’ vol. ii, p. 407, 1826.--_Pomeroy, C. G._,
“Escape of Worms (17 Lumbrici) from the Navel of a Child,” ‘Bost. M.
and S. Journ.,’ vol. xxi, 1840.--_Prichard, A._, “Case of Lumbricus,”
‘Rep. of East York and North Lincoln Br. of Brit. Med. Assoc.,’ in
‘Brit. Med. Journ.,’ 1859.--_Royer_, “Case of Intestinal Perforation
by a Lumbricus,” report in ‘Lancet,’ 1856.--_Rumsey, N._, “Cases of
Lumbricus and Tænia associated with Hæmoptysis,” ‘Med.-Chir. Trans.,’
1818.--_Sandwith, H._, “Remarks on Worms in the Peritoneal Cavity,
with a case,” ‘Brit. Med. Journ.,’ 1861.--_Schleifer_, “Case of a
Deaf and Dumb Child restored after the discharge of Worms (87 Lumbrici
and innumerable Oxyurides),” from ‘Œsterr. Med. Wochensch.,’ in ‘Amer.
Journ. of Med. Sci.,’ vol. viii, p. 473, 1844.--_Schneider, A._, ‘Monog.
der Nemat.,’ s. 36.--_Idem_, “On the Nervous System of Nematoda,” from
the German by _Busk_, ‘Quart. Journ. Micr. Sci.,’ 1863.--_Schultze_,
“Case of Stuttering occasioned by Worms,” from ‘Med. Zeit.,’ in
‘Med.-Chir. Rev.,’ 1837.--_Sheppard_, “Case of _A. lumbr._ extracted
from an Abdominal Abscess,” ‘Brit. Med. Journ.,’ 1861.--_Smith, J.
N._, “Thirty-nine Specimens of _Ascaris lumbricoides_ in a Child,”
‘Bost. M. and S. Journ.,’ 1856.--_Spalding, P._, “Case of Worms (100
Lumbrici),” _ibid._, 1839.--_Stockbridge, T. G._, “Worm-trap (hooks and
eyes), a New Remedy,” _ibid._, vol. xxvii, p. 73, 1842-43; see also
Anon., A. M.--_Stockbridge, W._, “Mechanical Expulsion of Worms (by
metallic buttons),” _ibid._, vol. xxviii, p. 419, 1843.--_Van Beneden_,
‘Animal Parasites,’ l. c., p. 95; see also _Gervais_.--_Villemin_,
“Case of Death from Worms (about 18 specimens of _A. lumbr._),” from
‘L’Union Méd.,’ in the ‘Lancet,’ and rep. in ‘Dubl. Med. Press,’ vol.
xxxv, p. 327, 1856.--_Weinland_, in his ‘Essay,’ l. c., p. 88, and
in ‘Troschel’s Arch.,’ 1859, s. 283.--_Welsh, T._, “Curious Facts
respecting (symptoms produced by) Worms (_A. lumbricoides_),” art. ix
in the ‘Med. Papers communicated to the Massachus. Med. Soc.,’ vol. i,
p. 87, 1790.--_Wendelboe_, “Case of discharge of Worms (Ascarides?)
through the Skin,” from ‘Rep. of Roy. Soc. Copenhagen,’ in ‘Lancet,’
1836; see also _Neilson_.--_Williams, H. W._, “Exhibition of a Lumbricus
with a dress-hook attached,” ‘Rep. of Bost. Soc. for Med. Improv.,’ in
‘Bost. M. and S. Journ.,’ vol. lvi, p. 163, 1857.--_Wilson, J._, “On
the prevalence of Lumbrici in China,” in his ‘Med. Notes on China,’
London, 1846.--_Woodman, W. B._, “Case of Convulsions, &c., arising from
Lumbricoid Worms,” ‘Med. Times and Gaz.,’ 1863.--_Young, W._, “Cases in
which Lumbrici were evacuated by Ulceration through the Parietes of the
Abdomen,” ‘Lond. Med. Gaz.,’ from ‘Glasgow Med. Journ.,’ 1828; rep. in
‘Lond. Med. and Surg. Journ.,’ vol. i, p. 564, 1828.



SECTION IV.--PART I.--ACANTHOCEPHALA (Thornheaded worms).


_Echinorhynchus gigas_, Goeze.--There is but one recorded instance
of the occurrence of this entozoon in the human body. This is the
oft-quoted case by Lambl, given in the ‘Prager Vierteljahrschrift’ for
1859. Lambl, indeed, described it as a separate species (_E. hominis_),
but as the worm was a sexually-immature female, its identification with
_E. gigas_, notwithstanding Schneider’s great authority, can hardly
be regarded as absolutely certain. The worm was found in the small
intestine of a boy of nine years, and measured only rather more than
the fifth of an inch in length. As Leuckart hints, the worm may be
_Echinorhynchus angustatus_, or possibly the _E. spirula_, a species
found in various South American apes (_Cebus_ and _Jacchus_), and also
in the Barbary ape (_Inuus_).

In 1872, Welch, unaware of Lambl’s case, announced the discovery of “the
presence of an encysted Echinorhynchus in man.” The minute parasite
found by him occurred in a soldier, thirty-four years of age, who died
at Netley, but who had contracted the worm in India. “It was situated
in the jejunum, immediately beneath the mucous coat, and formed an oval
prominence in the interior of the gut.” Speaking with great confidence,
this able microscopist further remarks:--“The character and arrangement
of the hooklets unequivocally shadowed forth a species of Echinorhynchus
for the first time discovered as a representative of the Acanthocephala
in the human body.” Along with his elaborate description Welch gives
several figures; but these, so far from producing conviction as to
the accuracy of his inferences, have unfortunately led me to believe
that the parasite in question would be more properly referred to
the _Pentastomidæ_. But for Heller’s acquiescence I might have more
fittingly noticed this worm elsewhere. Davaine falls into the same
view, and moreover accepts Lewis’s “Echinorhynque du Chien,” which I
have shown to be a nematode (_Cheiracanthus robustus_). It is thus that
serious errors creep into the literature of parasitism.

In the adult state the female _Echinorhynchus gigas_ is a huge species,
occasionally reaching two feet in length, with a breadth of one third
of an inch. The male rarely exceeds three inches. This worm is common
in swine, both wild and domesticated. According to Schneider the
embryos take up their residence in the grubs or larvæ of the cockchafer
(_Melolontha vulgaris_), a discovery which very readily explains the
manner in which hogs become infested. Whether _E. gigas_ be a human
parasite or not, it is certainly very injurious, not to say destructive,
to swine. Although this parasite must be quite common in England I have
experienced great difficulty in procuring specimens. In the second book
of this work I shall give some interesting particulars furnished by
the memoir of Prof. Verrill and privately by Mr George Wilkins. (See
‘Parasites of the Pachydermata’.)

BIBLIOGRAPHY (No. 35).--_Blanchard_, in ‘Cuvier’s Règne Animal,’ tab. 35
(good fig.), and in ‘Ann. d. Sci. Nat.,’ ser. xii.--_Bremser_, ‘Icones,’
tab. vi.--_Cobbold_, “Parasites of the Hog,” the ‘Veterinarian,’
1875.--_Idem_, ‘Manual,’ l. c., p. 123.--_Davaine_, l. c., ‘Syn.,’ p.
83.--_Diesing_, l. c., ii, p. 2.--_Dujardin_, l. c., p. 503.--_Goeze_,
l. c., s. 143 (good figs.).--_Gurlt_, l. c., s. 367.--_Heller_,
‘Darmschmarotzer,’ l. c., s. 663.--_Lambl_, l. c., _supra_, Feb.,
1859.--_Leuckart_, l. c., Bd. ii, s. 729; also in ‘Bibl. Univ.’ for
March, 1863, and in ‘Ann. Nat. Hist.,’ vol. xii, 1863.--_Owen_, l. c.,
in ‘Todd’s Cyclop.’ (figs. after Cloquet).--_Rudolphi_, ‘Synops.,’ pp.
63 and 310.--_Schneider_, in ‘Arch. f. Anat. und Phys.,’ 1868.--_Idem_,
in ‘Sitzungsb. der Oberhess. Gesellsch. f. Nat.,’ &c., 1874 (quoted by
Leuckart); see also ‘Ann. Nat. Hist.,’ 4th series, vol. vii, p. 441,
1871.--_Verrill_, ‘The external and internal Parasites,’ &c., l. c.,
p. 109.--_Welch_, “The presence of an Encysted Echinorhynchus in Man,”
‘Lancet,’ Nov. 16, p. 703, 1872.--_Westrumb_, ‘De Helm. Acanth.’ (good
figs.), 1821.


SECTION IV.--PART II.--SUCTORIA (Leeches)

As explained in the Introduction we must regard the Leeches and
many allied forms of Suctorial Annelids as creatures possessed of
semi-parasitic habits. They are, perhaps, something more than what
Van Beneden styles “free parasites”--an expression which almost looks
like a contradiction of terms. I cannot here, however, stop to discuss
questions which lie, as it were, on the border-land of parasitology.
Three species of leech are more or less commonly employed in medicine.
These are the grey leech (_Sanguisuga medicinalis_, Savigny), the
green-leech (_S. officinalis_, Sav.), and the dragon-leech (_S.
interrupta_, Moq.-Tandon). The two former abound in Central and Southern
Europe, being also present in North Africa, the last named inhabiting
Barbary and Algeria. So abundant are leeches in the country bordering
the Mediterranean that during the invasion of Egypt by Napoleon the
French soldiers suffered seriously from their attacks. When the men
lay down to drink, the leeches (_Hæmopis sanguisorba_, Sav.) affixed
themselves to their mouths and nostrils, producing serious distress.
They also attacked horses, camels, and cattle. In like manner the
Ceylon and Philippine Island leeches (_S. ceylonica_, Moq.-Tand., or
_S. tagalla_, Meyen), of which there are several varieties, prove
exceedingly troublesome to Europeans. These leeches, not being aquatic
forms, occupy woods and damp places. Unless the limbs of travellers are
well protected, the presence of the blood-suckers is soon discovered by
the trickling of blood from the limbs and lower part of the body. The
leeches even sometimes creep up to the neck and other adjacent parts.
These “free parasites” also attack horses, causing much loss of blood.
Terrestrial leeches abound more or less in all warm countries. Sir J.
Hooker encountered them in the Himalayas, and they are common in China,
Japan, Java (_S. Javonica_, Wahlberg), and other eastern parts. They
likewise abound in Brazil and Chili. The American leeches for the most
part belong to the genus Hæmenteria (_H. Mexicana_, _H. officinalis_,
and _H. Ghiliani_, Filippi). The last named is common in Brazil, the
other two being Mexican forms. Another species, which is blind, has
been found in Brazil by F. Müller (_Cyclobdella lumbricoides_). Not
only the above-named species, but also many other kinds of leeches are
in the habit of attacking man and the domestic animals, but the subject
is too extended and special to be fully dealt with in this work. Almost
a legion of species are known as externally parasitic upon Fishes,
Chelonian and Batrachian reptiles, Crustaceans, and Echinoderms.

BIBLIOGRAPHY (No. 36).--_Blainville_, ‘Dict. des Sci. Nat.,’ tom.
xlvii, p. 257.--_Brandt_ (und _Ratzeburg_), ‘Medicin. Zoologie,’ Bd.
ii.--_Brightwell_, ‘Ann. and Mag. Nat. Hist.,’ ix, 1842.--_Diesing_,
‘Syst.,’ vol. i, p. 465, and “Revis. der Myzelminth. (Abth.
Bdellideen),” in ‘Sitzungsb. der math.-nat. Cl. d. k. Akad. der
Wissensch.,’ Bd. xxxiii, s. 473.--_Ebrard_, ‘Compt. Rend.,’ 1856, p.
1012.--_Idem_, ‘Monogr. des sangues Méd.,’ 1857.--_Filippi, De_, ‘Mem.
Accad., &c., Torino,’ and in ‘S. und K. Zeitsch.,’ 1829.--_Idem_,
“Nuovo genere,” &c., in ‘Gaz. Med. Lombard,’ 1849.--_Grube_, ‘Fam. d.
Annelid.,’ s. 109.--_Hofmeister_, in ‘Burmeister’s Zeitung für Zool.,’
1848.--_Johnson_, ‘Treatise on the Medicinal Leech.’--_Leuckart_, l.
c., Bd. ii, s. 634-739 (with many refs.)--_Leydig_ (“Anat.”), ‘S.
und K. Zeitsch.,’ Bd. i.--_Moquin-Tandon_, ‘Monogr. de la fam. des
Hirudinées,’ 1846.--_Idem_, in his ‘Medical Zoology’ (Hulme’s edit.),
1861, p. 137.--_Müller, F._, in ‘Archiv f. Naturg.,’ 1846.--_Pereira_,
in his ‘Materia Med.,’ vol. ii, p. 2197, 1853.--_Savigny_, ‘Descript. de
l’Egypte,’ 2nd edit.--_Idem_, ‘Syst. des Annélides,’ 1820.--_Schmarda_,
‘Neue wirbell. Thiere,’ Bd. i (quoted by Leuckart).--_Virey_ (and
_Serullas_), in ‘Journ. Pharm.,’ 1829, p. 614.--_Wagener_, in
‘Troschel’s Archiv,’ 1858, Bd. i, s. 244 _et seq._--_Wahlberg_, in
‘Œfvers. Kongl. Vetensk. Akad. Forhand.,’ Stockholm, 1855.


SECTION IV.--PART III.--ARACHNIDA (Pentastomes, Mites, Ticks).

The Trachearian division of the Arachnida comprises a few internal
parasites that attack man, and many ectozoa which are parasitic upon man
and animals. The species can only be noticed very briefly.

_Pentastoma tænioides_, Rudolphi.--In the system of classification
adopted by Diesing, this entozoon and its allies are placed in the
division _Cephalocotyleen_ and therefore, in association with the
Cestodes, with which, however, it has no structural affinity. It was
long ago pointed out by Van Beneden, T. D. Schubart, Leuckart, and
others, that the pentastomes were Acarine and Lernæan Arthropods; the
genus being osculant between the Acaridæ and Lernæidæ. The whole subject
is discussed in Leuckart’s profound memoir quoted below.

The adult _Pentastoma tænioides_ is characterised by the possession
of a vermiform, lancet-shaped body, flattened at the ventral surface,
attenuated posteriorly, and marked transversely by about ninety rings
(fig. 50, 1 and 2). The cephalo-thoracic segments are continuous with
the body, each supporting a pair of strong retractile chitinous claws;
four in all. The head is truncated, furnished with an oval mouth, armed
with a horny lip. The integument of the body is perforated with numerous
respiratory openings or stigmata. These are wanting in the cephalic
segment. In the larval state (══ _Pent. denticulatum_) the body is armed
with numerous rows of small, sharply pointed spines. The adult female
measures from three to four inches in length, but the male is only
about an inch long. The genital aperture of the female is situated at
the extremity of the tail, that of the male being placed at the front
part of the abdomen in the middle line. The mode of reproduction is
oviparous, accompanied by a subsequent and complete metamorphosis.

[Illustration: FIG. 50.--_Pentastoma tænioides._ (1) Male and (2)
female, of the natural size. The egg and embryo highly magnified. After
Leuckart.]

In the mature condition this parasite infests the nostrils, and frontal
sinuses of the dog and wolf, and also, though more rarely, the nasal
cavities of the horse and sheep. In the pupal and larval states it
sometimes occurs in the abdominal and thoracic cavities of the human
body, but it is more frequently found in herbivorous mammals, such as
the sheep, deer, antelope, peccary, porcupine, guinea-pig, hare, and
rat. According to Creplin, it infests the domestic cat. In these animals
and in man the young worms occupy little cysts within or upon the
peripheral parts of the liver and lungs. I have occasionally found them
free in the cavities of the abdomen and pleura.

In the course of the development of this entozoon, Leuckart recognises
four well-marked stages. The _first_ is that of the embryo with a boring
apparatus. In the _second_ stage, the embryo has become transformed
into a motionless pupa. The _third_ is the ordinary larval condition
characterised by numerous rows of small spines in addition to two
pairs of double claws. The _fourth_ is the sexually-developed stage,
furnished with a simple hook-apparatus, and without integumentary
denticles. “Our Pentastomes, therefore,” says Leuckart, “exhibit two
kinds of larval forms, an earlier and later one, such as takes place
in other animals; this also occurs even in insects (_Strepsiptera_ and
_Meloidæ_), only that, in our case (_i. e._ in _Pentastoma_), both do
not immediately follow one another, but are separated by a resting
condition, which I have designated as the pupa stage. In choosing this
name I do not mean to express a complete identity of this intermediate
state with the pupal sleep of insects.”

[Illustration: FIG. 51.--Upper third of the body of _Pentastoma
denticulatum_. Original.]

So far as my own observations extend, the pupa, in its later stages,
closely resembles the free larva; but, as Leuckart points out, the
earlier stages are very different. The embryo, after encystation,
repeatedly casts its skin, and during the intervals of these several
successive moultings, the young animal makes rapid growth, accompanied
by a series of structural changes. Passing through these it at length
acquires the perfected larval state (_P. denticulatum_).

As regards the occurrence of this entozoon in the human body, the best
account is that given by Frerichs. As quoted in my previous work from
Murchison’s edition of Frerichs’ well-known clinical treatise, the
German _savant_ remarks:--“The Pentastoma is a parasite which has only
recently been discovered in the human subject, but it is, nevertheless,
far more common in the human liver than the echinococcus. It is devoid
of clinical importance, because it does not give rise to any functional
derangements. Pruner (‘Krankheit des Orients,’ 1847, s. 245) was the
first who pointed out the existence of the Pentastoma in the human
liver. On two occasions he found an encysted parasite in the liver of
negroes at Cairo, the nature of which, however, he did not accurately
determine. Bilharz and Von Siebold (‘Zeitschr. für Wissench. Zoologie,’
Bd. iv, s. 63) recognised in it a new variety of Pentastoma, to which
he gave the name of _P. constrictum_. In Germany the Pentastoma was
found in the human liver by Zenker (‘Zeitschr. f. ration. Med.,’ 1854,
Bd. v, s. 224); it occurs, however, not only in this gland, but also
in the kidneys, and in the submucous tissue of the small intestine
(Wagner). The parasite is by no means rare with us. Zenker, at Dresden,
succeeded in finding it nine times out of 168 autopsies; Heschl, at
Vienna, met with it five times out of twenty autopsies; Wagner, at
Leipsig, once in ten. According to Virchow, it is more common in Berlin
than in Central Germany. During six months at Breslau I met with it
in five out of forty-seven dead bodies. The Pentastoma-endemic in
Germany is not identical with that which occurs in Egypt; the former is
the _P. denticulatum_ of Rudolphi.” This clear statement of Frerichs
is valuable; but, as Murchison has also pointed out, there is some
discrepancy between Frerichs and Küchenmeister’s record of Zenker’s
experience. According to Küchenmeister, Zenker met with the Pentastoma
thirty times in 200 autopsies.

Although from a purely clinical point of view, and speaking generally,
this worm, as Frerichs says, can claim little attention, yet, as we
shall see (when treating of the parasites of the dog), it occasionally
proves fatal to the canine bearer. Not only so, it may even occasion
severe inconvenience to the human bearer. Quite recently a remarkable
instance of this kind occurred in Germany, some notice of which appeared
in the ‘Medical Times and Gazette,’ Jan. 4th, 1879, as follows:

“Dr Landon of Elbing (‘Berl. Klin. Wochenschrift,’ No. 49, 1878)
relates the case of a workman, aged forty-two, who soon after the
Franco-German campaign of 1870 was laid up with pain in the hepatic
region, jaundice, and gastric disturbance, which symptoms persisted more
or less until 1874, when he came under Dr Landon’s care with an attack
apparently of perihepatitis. It then appeared that since 1871 he had
also suffered from severe attacks of epistaxis, which occurred often
twice in the same day. The patient complained of a feeling of painful
pressure in the left nasal cavity, but with the speculum nothing but a
moderate degree of inflammatory swelling could be detected. Suddenly, at
Easter, 1878, a parasite was dislodged from the left side of the nose by
a violent sneeze, and from that moment the epistaxis has not occurred.
Its cause proved to be the _Pentastoma tænioides_.”

As the full-grown parasite occupies the nasal chambers of the dog, it is
clear that the act of sneezing will be liable to transport the eggs and
their contained embryos to the face and other exposed parts of persons
who fondle dogs. In this way the germs will readily gain access to the
human mouth. Ordinarily, the germs are introduced into the human stomach
with uncooked vegetable food and fruits, to which they adhere after
expulsion from the animal’s nostrils. The slimy nasal mucus secures this
attachment, especially when it has become dry by exposure to the air.
On reaching the stomach the embryos escape the egg-coverings and bore
their way directly to the liver and other viscera, in which organs they
become encysted and undergo the pupal transformation. Eventually they
acquire a length of 2 to 2-1/2 lines (_P. denticulatum_). After a while
the capsules enclosing the larvæ undergo calcareous degeneration, the
parasite perishing.

In the case of dogs it is easy to perceive that when the animals are
engaged in devouring the flesh of herbivora, the liberated larvæ will
often come in contact with their noses. In this way contraction of the
body, aided by the integumentary denticles, will secure their entrance
into the nasal cavities. For our own security, therefore, we should
avoid contact with dogs which frequent butchers’ shops and knackeries,
and be sure that our market-garden fruits and vegetables are carefully
washed before they are brought to table.

_Pentastoma constrictum_, Von Siebold.--This parasite is at present
only known to us in the immature condition; unless, indeed, as is by no
means improbable, the adult worm has been described under some other
name. It was first discovered by Pruner on two occasions in negroes,
and he also subsequently found two specimens of the worm preserved in
the Pathological Museum at Bologna, which had been removed from the
human liver. Pruner also found it in the giraffe. Bilharz afterwards
frequently detected it in the livers of negroes at Cairo. It differs
from the larval form of _P. tænioides_ in not possessing integumentary
spines; moreover, it is a much larger parasite. The cephalothorax is
furnished with four foot-claws, and the elongated abdomen displays
twenty-three rings placed at tolerably regular intervals. The anterior
part of the animal is obtusely rounded off, the caudal end being
conical. The worm usually attains a length of rather more than half an
inch, whilst the breadth scarcely exceeds a line.

An extremely interesting account of this worm has been published by
Prof. Aitken, accompanied with illustrations by Dr H. C. Gillespie,
taken from specimens in the Pathological Museum at Netley. Two cases
are recorded. In one of these the encysted worms were found in the
liver and lungs, and in the other in the liver only. In Dr Crawford’s
account of the post mortem in the last-mentioned case, Prof. Aitken
quotes him as saying: “These worms varied in length from an inch to an
inch and a half, and were found coiled up like a watch-spring, in small
sacs scattered throughout the whole organ.” The patient was a private
of the 1st West India Regiment, and died at Bathurst, Gambia, in 1854.
In the other case, where the lungs and liver were infested, the patient
was an African, about twenty-one years old, who had enlisted into the
5th West India Regiment at Up Park Camp, Jamaica. He had, a few months
previously, come from the slave depôt at Rupert’s Valley, St Helena.
According to the post-mortem report, furnished by Mr Kearney (staff
surgeon), the lower lobe of the right lung contained one or two yellow
specks. “When cut into, worms were seen regularly encysted in its
substance.” The surface of the liver was dotted over “with about twenty
or thirty yellow specks, similar to those seen in the lung.” The longest
of these specimens was a trifle less than three quarters of an inch.

[Illustration: FIG. 52.--_Pentastoma constrictum._ Magnified four
diameters. After Bilharz.]

Whether _Pent. denticulatum_ be or be not devoid of clinical interest,
it is quite clear from Aitken’s account that _P. constrictum_ is a
formidable parasite and one that occasionally proves fatal to the
bearer. As his remarks suggest, a parasite that can produce both
pneumonia and peritonitis is not a creature that either the physician
or the sanitarian can afford to ignore. Lastly, I must again express my
belief that the so-called _Echinorhynchus_, described by Welch, if it
be not the _Pentastoma denticulatum_, must either be referred to _P.
constrictum_ (in an early larval condition), or to some other hitherto
undescribed pentastomatoid larva.

BIBLIOGRAPHY (No. 37).--_Aitken, W._, “On the occurrence of _Pentastoma
constrictum_ in the Human Body as a cause of painful Disease and
Death,” repr. from the ‘Science and Practice of Medicine,’ 4th
edit., 1865.--_Bellingham_, in ‘Ann. Nat. Hist.,’ vol. xiv, p.
162.--_Blanchard_, in ‘Ann. des Sci. Nat.,’ ser. 3, t. viii, and
in ‘Règn. Anim.’ (with figs.).--_Cobbold_, ‘Entoz.,’ p. 393 _et
seq._--_Idem_, in ‘Quart. Journ. Med. Sci.,’ 1859, p. 205.--_Idem_
(“_P. cephalophi_”), in ‘Linn. Trans.,’ xxii, p. 357, and xxiii, p.
350.--_Idem_, in ‘Zool. Soc. Proc.,’ 1861, p. 124.--_Diesing_, ‘Syst.,’
i, p. 609.--Idem, ‘Revis. der Cephalocot.,’ s. 327.--_Frerichs_ (l. c.,
in text), vol. ii, p. 276.--_Klob_ (und _Schroff_), in ‘Gesellsch. d.
Aerzte,’ Wien, 1860.--_Küchenmeister_, l. c., i, s. 370, Eng. edit.,
tab. viii.--_Idem_ (with _Van Beneden_), in ‘Bullet. Acad. Belg.,’
xxii (with figs.), 1855.--_Landon_ (quoted in text).--_Leuckart_,
in ‘Zeitsch. f. rat. Med.,’ 1857; see also “Obs. on the development
and early condition of the _Pent. tænioides_,” in ‘Ann. Nat. Hist.,’
vol. iii, 3rd series, 1859; also my translation of his “Further
Observations on the development of _P. tænioides_,” from ‘Henle
and Pfeufer’s Zeitsch.,’ in the ‘Quart. Journ. of Micr. Sci.’ for
1859.--_Idem_, ‘Bau und Entwicklungsgeschichte der Pentastomen, nach
Untersuchungen besonders von _P. tænioides_ und _P. denticulatum_,’
Leipzig, 1860.--_Moquin-Tandon_, ‘Med. Zool.’ (Hulme’s edit.), “The
Linguatula,” p. 329.--_Pruner_ (“Nematoideum”) in ‘Krankh. d. Orient.,’
1847.--_Schubart_, ‘S. und K. Zeitschr.,’ Bd. iv.--_Welch_, see Bibl.
No. 36.--_Zenker_, in ‘H. und Pf. Zeitschr. f. rat. Med.,’ 1854, s. 212
(with figs.).

[Illustration: FIG. 53.--_Demodex folliculorum_, var. _caninus_. _a_,
Female; _b_, male. Viewed from below and in profile. Magnified 300
diameters. After Mégnin.]

The ectoparasitic arachnidans comprise a great variety of mites and
ticks (_Acaridæ_ and _Ixodidæ_) more or less proper to man, and also
a number of creatures which, though hardly to be reckoned as human
parasites, are apt to transfer themselves from animals to man. Little
more than an enumeration of the forms is possible here. The Common Scab
or Itch insect (_Sarcoptes scabiei_) forms the type of a great variety
of arachnids, generally spoken of as different species according to the
host they dwell upon. Mégnin, however, in his beautiful memoir, quoted
below, regards most of the forms of this genus (found on the horse,
hog, sheep, dog, wolf, and other animals) as mere varieties. In man the
female Acarus burrows beneath the skin, forming galleries or curved
channels, in which she deposits her eggs. The irritation produced is not
alone due to these excavations, but to the presence also of a poison
which the mite discharges when feeding. The _Sarcoptes crustosæ_ of
Fürstenberg, producing the Norway itch, is a variety, if, indeed, it
can be called as much. Under the frightful name of _Dermatophagoides
Schérémétewsky_ two parasites found on an herpetic patient have been
described as new to science by M. Bogdanoff, but Mégnin points out
that these Acari are only female and young male representatives of his
_Chorioptes setiferus_ (var. _bovis_) respectively. In Newfoundland,
Dr Le Roy de Méricourt discovered a singular species upon an officer
who had come from Havannah (_Tyroglyphus Méricourti_, Laboulbène). It
possesses enormous palpi, as in the genus _Chyletus_ to which Robin
refers it. Another ectozoon, placed by Mégnin and others amongst the
lowest types of Arachnida, is the well-known _Demodex folliculorum_. It
is a gregarious species, a dozen or more examples often being present in
a single dilated hair follicle. Though disfiguring to the human face it
produces little harm. M. Gruby made it out to be a very common parasite,
infesting forty out of sixty persons; but Mégnin, in his brochure (l. c.
infra, p. 119), shows this statement to be an exaggeration. It infests
on the average not more than one in ten persons. According to Gruby,
moreover, a single follicle in the dog may contain 200 of these mites,
another statement which Mégnin deems unreliable. The _Demodex_ of the
dog is only a variety (fig. 53). Many other human Arachnids have been
found, some of which appear to be genuine species, whilst others are
accidental, so to speak. Of the former kind, perhaps we may reckon
the two species discovered by Hessling (_Cœlognathus morsitans_ and
_Entarsus cancriformis_). Of the latter sort, those found by Busk,
Simon, and Bory de St Vincent may be cited. The mite found in Simon’s
case was the _Dermanyssus avium_, which infests cage-birds. Probably it
was the same species which Bory found on a lady; but in Busk’s negro
sailor the mite may have been _D. gallinæ_ of the common fowl. Differing
from the mites, proper, and also from the true ticks, are some bug-like
forms called Argades. The two best known are the Miana bug of Persia
(_Argas persicus_) and the Chinche of Columbia (_A. chinche_). Like
their congener infesting pigeons (_A. reflexus_) these parasites are
terrible blood-suckers. The bite of the Persian bug is so venomous as
to have occasioned death. Various species of tick have been known to
attack man, but the species have not been well determined. Although
a human form has been described (_Ixodes hominis_, Koch), yet it is
more probable that the species usually attacking man are the same as
those known to infest the domesticated animals. In this list we may,
therefore, reckon _Ixodes nigra_, _Ix. bovis_, _Ix. ricinus_, and _Ix.
reduvius_. Cases in which one or other of these ticks occasioned much
pain and distress are recorded by Hussem, Raspail, and Dr Cosson.
Besides these there is a formidable tick well known at Angola (_Ix.
monbata_). Its habits are like those of the common bed-bug. Severe pain
comes on two hours after the person is bitten. It likewise attacks
animals. The _Ix. carapato_ is similarly troublesome in Brazil.
Another very disgusting arachnid liable to attack man is the _Galeodes
araneoides_. This large spider-like creature, two inches in length,
commonly attacks camels and has an extremely venomous bite. One or
more species of the dung-beetle mites (Gamasidæ) have also been known
to fasten themselves on man. According to Latreille, they first get
attached to the clothes of travellers, whence they pass to his body,
and there shift about, producing great torment. Another disagreeable
arachnid is the little harvest bug (_Leptus autumnalis_), which not
only excites irritation during its crawling motion on the human skin,
but even succeeds in burying itself near the hairs. The irritation
thus produced is almost unbearable. This mite attacks various animals,
especially dogs and cats. I myself once suffered severely from this
species in consequence of fondling a young wild rabbit which, as I
afterwards discovered, was much infested. When the parasites had
reached my left arm-pit they occasioned extreme torture. I have known
these autumnal spiders to produce small suppurating boils on the
abdomen. I may add that Dr Tilbury Fox has brought under my notice
an instance where the hexapod larva of another species (probably
_Trombidium cinereum_) was found to have occasioned severe irritation in
a child.

BIBLIOGRAPHY (No. 38).--_Alibert_, ‘Maladies de la Peau,’ Paris,
1833.--_Audouin, V._, art. “Arachnida,” in ‘Todd’s Cyclop.,’ vol. i,
1836.--_Beneden, Van_ (_et Gervais_), ‘Zool. Med.,’ 1859.--_Bourguignon_
(_et Delafond_), in ‘Rec. Vét.,’ 1856.--_Idem_, in ‘Mém. de
l’Institut.,’ 1862.--_Cobbold_, “Case of _Leptus_ producing Boils,” in
‘Worms,’ p. 140, London, 1872.--_Gamgee_, ‘Our Domestic Animals in
Health and Disease,’ Edin., 1861.--_Gerlach_, ‘Kraetze und Räude,’
1857.--_Hebra_, in ‘Oester. Jahrb.,’ 1864.--_Hering_, ‘Die
Kraetzmilben,’ Stuttgard, 1845.--_Krabbe_, “Husdyrenes paras. Mider.,”
‘Tidssk. f. Vet.,’ Rœk. 2, Bd. iii.--_Küchenmeister_, l. c., 1855, s.
412 (good figs.).--_Mégnin_, ‘Monographie de la tribu des Sarcoptides
psoriques.’ (This work contains a full bibliography and numerous
beautiful plates; see also Review in the ‘Veterinarian,’ Aug., 1877, p.
563).--_Idem_, “Mémoire sur un nouveau Symbiote (_Chorioptes_, Gerv.),”
‘Journ. de l’Anat. et de la Physiol.,’ 1872.--_Idem_, “Mém. sur un
nouvel Acarien,” _ibid._, 1873.--_Idem_, “Mém. sur les Hypopes,”
_ibid._, 1874.--_Idem_, “Mém. sur l’organisation et la distribution
zoologique des Acariens de la famille des Gamasidés,” _ibid._,
1876.--_Idem_, “Mém. sur les métamorphoses des Acariens en général, et
en particulier sur celles des Trombidions,” ‘Ann. des Sci. Nat.,’
1876.--_Idem_, “Des conditions de la contagion de la gale des animaux à
l’homme,” ‘Arch. générales de Méd.,’ 1876.--_Idem_, “Mém. sur le
_Demodex folliculorum_ (Owen),” ‘Journ. de l’Anat. et de la Physiol.,’
1877.--_Moquin-Tandon_, ‘Elém. de Zool. méd.’ (Hulme’s edit., p.
302-328), 1861.--_Williams_, in his ‘Veterinary Surgery’ (good figs.,
reproduced from Gamgee’s translation of ‘Gerlach,’ &c.), 1872.


SECTION IV.--PART IV.--CRUSTACEA (Gammaridæ).

Although multitudes of small Crustaceans are parasitic upon fishes, and
some few of them adhere to oceanic mammals (Cetacea), I am sceptical
as to the parasitism of Crustacea either in or upon man. Many of the
Amphipodous Gammari lead a sort of free parasitic existence, and they
are themselves very liable to harbor larval parasites. As regards human
parasitism from this source the only records known to me are those
quoted below.

BIBLIOGRAPHY (No. 39).--_Banon_, “Freshwater Shrimp, or _Gamarus pulex_
(said to have been passed per anum),” ‘Rep. of Path. Soc. of Dublin,’
in ‘Dub. Med. Press,’ April 6, p. 351, 1864.--_Bartels_, “_Gamarus
pulex_ in the Human Subject, with a postscript by Troschel,” trans. by
Dr E. P. Wright, from ‘Verhandl. des Naturhist. verein. der Preuss.
Rheinl. und Westph.,’ in ‘Dubl. Med. Press,’ 2nd ser., vol. ix, p. 407,
1864.--_Wright, E. P._, ‘Remarks on Dr Banon’s Case’ (see Bartels).


SECTION IV.--PART V.--INSECTA (Coleoptera, Diptera, Hemiptera,
Aphaniptera).

Whilst very many flies, bugs, lice, and fleas persecute animals, not
a few of them also attack man. Several of the species are genuine
parasites, others are semi-parasitic, and others, again, are altogether
outside the border-land of parasitism in the ordinary sense of the term.
In fact, it becomes difficult to say where the line of parasitism should
be drawn. I cannot, however, ignore all notice of the insect tormentors,
whether strictly parasitic or not.

At least fifty different species have been regarded as playing the rôle
of parasitism in man. Amongst the Coleopterous parasites none is more
authentic than _Blaps mortisaga_. At least half a dozen such cases
have occurred. Mr Hope’s catalogue of insects producing parasitism in
man gives three examples of _scolechiasis_ from this source. Sir J.
R. Cormack published a fourth case, and I have recorded a fifth. In
this instance I received the living larva from Dr Horne, of Barnsley,
who procured it from an infant eleven weeks old. In my ‘Introductory
Treatise’ I have alluded to the case of the girl Riordan, who not only
passed per anum upwards of 1200 larvæ, but also several perfect insects.
The case was first reported by Pickells, Thomson, and Bellingham. One
of the other authentic cases, in which only a few larvæ were present,
was recorded by Patterson, of Belfast, and the third case by Bateman.
Mr Hope’s ‘Catalogue’ originally appeared in the ‘Transactions of the
Entomological Society,’ being afterwards published in the pages of the
‘London Medical Gazette,’ 1837. Patterson’s case was also, I believe,
first communicated to the Entomological Society.

As regards the mode in which the maggot gained access to the child in
Horne’s case, it was not easy to decide; but in the case of the girl
Riordan the mode of ingress was sufficiently explained. The _Blapsidæ_,
as a family, are closely allied to the meal-worms, and, like most of
the _Tenebrionidæ_, are black and foul-smelling beetles, frequenting
dark and damp situations, from which they escape only at night. The
family comprises numerous species, of which probably not more than three
are found in this country. They are abundant in Africa, especially in
Egypt, where (according to Fabricius, as quoted by Westwood, Figuer,
and others) the women eat _Blaps sulcata_ cooked with butter in order
to make themselves grow fat. The insects are also employed as specifics
against ear-ache and the bite of the scorpion. The superstitious notion
of a “charm” is generally at the bottom of these domestic remedies.
In the girl Riordan’s case, as Westwood observes (when epitomising
Pickell’s account), the parasites, as such, “probably originated in an
absurd and superstitious practice, which she had for some time followed,
of drinking daily for a certain time a quantity of water mixed with
clay, taken from the graves of two Catholic priests, and eating large
pieces of chalk. One of these beetles was immersed repeatedly in spirits
of wine, but revived after remaining therein all night, and afterwards
lived three years.” The intolerance of light shown by the perfect insect
seems to be equally shared by the larva. Of this fact I had repeated
evidence by observing the behaviour of the living specimen sent to me by
Dr Horne. Thus, when, on February 5th, 1877, I placed the maggot on the
surface of some moist mould, scarcely half a minute elapsed before it
commenced to bore its way downwards, and in less than a minute all but
the tip of the tail had disappeared. In like manner, when, on the 7th,
I raised the lid of the box, and found the maggot on the surface of the
soil, it almost instantly proceeded to bury itself. Hope’s list records
no less than nine instances of parasitism in man from the larvæ of
_Tenebrio molitor_, and he gives a score of other Coleopterous insects
which he regarded as human “intestinal worms.” Undoubtedly a large
number of insect larvæ do get introduced into, and actually live within
the human intestines.

Numerous cases of this sort have come under my observation, but it often
requires a profound knowledge of entomology to determine the species.
Several examples of œstridean larvæ occur amongst them. For one example
of _Œstrus hominis_ I am indebted to Mr Higginson, of Liverpool, who
obligingly supplied me with notes of the case. Dr Kirk presented me
with a small bot which he removed from Livingstone’s leg. I afterwards
deposited the African bot, in his name, in the Hunterian collection.
Bates speaks of an Œstrus in Brazil producing boils in human flesh.
Westwood quotes similar instances. Of these, one was extracted from the
thigh by Dr Brick. Mr Doubleday, the entomologist, extracted one from
his own leg, and M. Goudot, another entomologist, was also victimised
in the same way. Both of these _savans_ were travelling in America at
the time. Two cases from South America were also recorded by Howship. In
one the larva lodged in the back; in the other in the scrotum. Humboldt
noticed that the Indians were much infested by Œstridæ. Three cases
are severally recorded by Roulin, Guérin, and Audouin. Mr Stroop also
mentions a case in which an Œstrus was removed from an ulcer on the
shoulder of a boy in Texas. Another kind of bot known as the Macaco worm
(_Cuterebra noxialis_) occasionally attacks man, but more frequently
cattle and dogs. For one example, taken from the leg of a negro, at
Belize, British Honduras, I am indebted to Dr Dobson (A. M. D., Netley).
Hope’s list records five cases of bots of _Œstrus hominus_, one of
_Œ. Guildingii_, one of _Œ. bovis_, and thirteen others (belonging to
the same genus) as having been noticed in man. Since his time many
additional cases have been recorded by J. M. Duncan and others. In like
manner a legion of cases in which the maggots of various Muscidæ have
been noticed, either in, upon, or from the human body. At a meeting
of the American Academy in April, 1859, Dr Leidy showed some larvæ of
the bluebottle fly vomited by a child; five larvæ of the flower-fly
(Anthomyia) from a physician’s own person (which had produced choleraic
symptoms); and nine examples of _Cuterebra noxialis_. I have myself
encountered numerous insect larvæ in medical practice. Amongst others
I have obtained the larvæ of _Anthomyia canalicularis_ in six or eight
separate instances. One set of specimens, identified by Wunderlich, was
sent to me by Dr Brandt, of Oporto. Drs Duffin, W. Fox, and Leared have
supplied me with others. The larvæ described in Farre’s case, not being
setose, must be referred to one or other of the Muscidæ proper. Mr
Hope gave nearly forty cases of this kind, referable to eight different
species of fly, and, as already implied, I have myself collected a great
variety of the maggots of Muscidæ passed by the bowel, besides others
obtained either from beneath the skin or from open ulcerations.

The flies hitherto noticed as supplying parasitic maggots in man are
_Musca domestica_, _M. carnaria_, _M. larvarum_, _M. nigra_, and perhaps
_M. Cibaria_, _M. stabulans_, and _M. Cæsar_. This last, a handsome fly,
is the species which proves so troublesome to sheep. The habit which
flies have of depositing their eggs in open wounds, when the victims
are asleep, is a fertile source of this kind of parasitism. Some of the
instances recorded by Kirby and Spence are revolting in the extreme.
They quote the cases which came under Mr Sell’s notice in Jamaica. In
one instance the flies were hatched in a neglected blister on the chest;
in another from the gums and inside of the cheek; and in a third, from
the nostrils of a negro, from whom 235 larvæ were expelled. The case of
the Lincolnshire pauper, Page, who was literally eaten up by maggots, is
almost incredible. An equally horrible instance, however, is recorded by
Cloquet. It is said that the Jamaica cases were all due to the larvæ of
the bluebottle fly (_M. vomitoria_). An instance of the same kind has
been recorded by Mr Knox (A. M. D.). Sufficiently revolting as these
cases are, the horrors attending them are eclipsed by the habits of
the larvæ of _Lucilia hominivora_. The best accounts of its habits are
those by M. Coquerel, M. Saint-Pair, and M. Vercammer. The insects lay
their eggs in the mouth and nostrils, and when the larvæ escape they
devour the tissues surrounding the buccal cavity, the pharynx, glottis,
frontal and nasal sinuses, even reaching the sockets of the eye. Several
Cayenne convicts have perished from the maggots of this fly, which is
also prevalent in Mexico. These are not, however, the only instances of
maggots gaining access to the nasal chambers. In a case recorded by Dr
Astros, of Aix, 113 were discharged from the nose of a woman; and M.
Legrand du Saulle records an instance where a number of larvæ occupied
the frontal sinuses of a girl, nine years of age. The larvæ produced
persistent headache and convulsions. In the case recorded by Wohlfart,
18 larvæ were discharged from the nose of an old man, and in the example
given by Latham several larvæ were obtained from the frontal sinuses of
a woman. Bracey Clark also gives an instance in which a bot was taken
from a woman’s jaw. Not improbably the well-known Indian disease, termed
peenash, or worm in the nose, is due to the presence of Œstridean larvæ.
Cases by Rustomjee and Lahory are quoted below. Possibly Stockett’s is
another of the same order. The case by Kilgour (Bibliog. No. 34) may be
another. I may add that Moquin-Tandon gives an instance of the discharge
of seventy-two bots, resembling those of the sheep, from a woman’s nose
(‘Journ. de Vandermonde’). The rat-tail maggots or larvæ of _Helophilus_
are parasitic. Two or three instances have been recorded from the horse.
I possess one from the human intestine. Kirby also quotes an instance
in which _Heloph. pendulus_ was obtained from the stomach of a woman
(‘Philos. Mag.,’ vol. ix, p. 366).

A vast number of non-parasitic insects are injurious to man and beast.
Inasmuch as they subsist at the expense of their victims and also adhere
to his person during their attacks for a shorter or longer time, they,
like the leeches, may be spoken of as free parasites. The leg-sticker
(_Stomoxys calcitrans_) penetrates through thick stockings, causing
blood to flow freely. The clegg of the West Highlands (_Hæmatopota
pluvialis_) also violently attacks man and beast, especially horses. The
mosquito (_Culex anxifer_), the gnats (_C. pipiens_, _C. annulatus_,
and _C. pulicaris_), and the midge (_Chironomus plumosus_) need only
be mentioned. The creeping gnat (_Simulium reptans_) is also very
annoying in Sweden. The rôle of the mosquito, as itself constituting
a parasite-bearer, will be again referred to in the closing pages of
this work (Book II, Section V). The bites of the tsetse (_Glossina
morsitans_), though so destructive to the horse, ox, sheep, and dog, are
not dangerous to man himself. According to Sir S. Baker, the seroot-fly,
or zimb of Bruce, which is a species of _Pangonia_, is excessively
annoying to travellers in Abyssinia. Amongst the hemipterous insects
the common bug (_Acanthia lectularia_) is sufficiently blood-thirsty;
but there is a far more sanguinary species of this kind in South
America. This is the pampas benchucha (_Conorhinus nigrovarius_). Our
distinguished countryman, Darwin, in his ‘Voyage,’ speaking of these
wingless insects, says:--“Before sucking they are quite thin, but
afterwards become round and bloated with blood. In less than ten minutes
the insect is changed from being as flat as a wafer to a globular form.”
This insect somewhat resembles our water-scorpion (_Nepa cinerea_), a
non-parasitic species whose bite causes severe pain, as does also the
wound inflicted by the water-boatman (_Notonecta glauca_). There are
other species of bug, such as the _Acanthia rotundata_ of Réunion Island
and _A. ciliata_ of Kasan, the bites of which are worse than that of the
common species. The fly-bugs also, such as the _Reduvius personatus_, so
common in France, and the _R. amænus_ of Borneo and Java, attack man,
although their especial habit is to attack and destroy other insects,
including bugs themselves. Other species or varieties of Reduvius (_R.
cruentus_, and _R. serratus_) attack man. The last named is an Indian
form, capable, it is said, of producing an electric shock.

Passing to the fleas, the most important and truly parasitic form is
the chigoe or gigger (_Pulex penetrans_). This abounds in tropical
America and the West Indies. The female insects only attack man, and
this they do for the purpose of securing a lodgment for their offspring.
They attack especially the soles of the feet, between the toes and
near the nails. In bad cases the whole of the foot becomes affected.
After the insect has penetrated the skin its body swells enormously and
becomes a mere bag of eggs. This swelling causes active inflammation,
which terminates in suppuration and the formation of open ulcers. The
chigoe also attacks various animals. In addition to the common flea
(_P. irritans_) other species infesting animals are said to attack man
occasionally. As regards those degraded types of insects known as lice I
can only afford space to remark that five species have been recognised
as human. These are the head-louse (_Pediculus capitis_); the louse of
the eyelids (_P. palpebrarum_); the clothes-louse (_P. vestimenti_);
the distemper louse (_P. tabescentium_); and the pubic louse (_P.
inguinalis_). The distress these creatures occasion is only fully known
to physicians who deal with the obstinate cutaneous affections caused
by their presence (_Phthiriasis_). Some of the lice found on negroes
and Greenlanders are regarded as distinct varieties. Lice are abundant
on animals, and some of the species are apt to transfer themselves
from one host to another. Thus the _Ornithomyia avicularis_ of cage
birds has been found on man, whilst one or more of the numerous species
infesting the common fowl are, by transfer, apt to produce a severe
phthiriasis in the horse. The lice of the fowl belong to the genera
_Leipurus_, _Liotheum_, _Menopon_, _Philopterus_, _Goniodes_, and
_Goniocotes_. The unsuitableness of man’s person as a habitation for
bird-lice should, however, check the fear which many persons have of
handling fresh-killed poultry and game birds. Poultry lousiness in man
is probably impossible from this source.

BIBLIOGRAPHY (No. 40).--_Arture_, “Obs. sur le ver nommé Macaque,”
in ‘Mém. Acad. des Sci.,’ Paris, 1753.--_Bates_, “Œstrus in
Man,” ‘The Naturalist on the Amazons.’--_Beneden, Van_, ‘Animal
Parasites and Messmates,’ 1876.--_Idem_ (with _Gervais_), ‘Traité
de Zool. Méd.’--_Blood, M._, “Case of Larvæ (_Musca sarcophaga_)
expelled alive in the Fæces,” ‘Beale’s Arch. of Med.,’ vol. iii,
p. 134, 1862.--_Brinton_ (similar case), ‘Arch. of Med.,’ vol.
iii, p. 133, 1862.--_Bouyer_ (quoted by Figuer), ‘Tour du Monde,’
p. 318, 1866.--_Clark, Bracey_, in ‘Linn. Trans.,’ vol. iii, 1797
(the jaw-case at p. 323), and vol. xv, 1827.--_Idem_, ‘Essay on
Bots,’ 1815.--_Cloquet, J._, “Case of Blindness from Worms (larvæ
of Musca) in the Eyes,” from ‘Arch. Gén. de Méd.,’ in ‘Lancet,’
1828.--_Cobbold_, “On _Blaps mortisaga_ as a Human Parasite,” ‘Brit.
Med. Journ.,’ 1877, p. 420.--_Idem_, “Entoz.” (‘Hope’s List.’), p.
416.--_Idem_, in ‘Worms’ (“Leptus,” &c.), p. 140, 1872.--_Coquerel_
(quoted by Figuer).--_Cormack, J. R._, “Exhibition of a Larva (_B.
mortisaga_) passed by a Child,” ‘Month. Journ. Med. Sci.,’ vol. i,
1841.--_Crumpe, S._, “History of a Case in which Worms (larvæ of a
beetle) were discharged from the Stomach,” from ‘Trans. of the Roy.
Irish Acad.,’ vol. vi, in ‘Med. Facts and Observ.,’ vol. viii, p.
229, 1800.--_Denny_, ‘Monog. Anoplurorum Brittaniæ,’ 1842.--_Duncan,
J. M._, “On the Occurrence of Bots in the Human Subject,” ‘Edin. Vet.
Rev.,’ vol. i, p. 275, 1858-59.--_Idem_, “The Larva of _Œstrus bovis_
in the Human Subject,” ‘Rep. of Edin. Med.-Chir. Soc.,’ in ‘Month.
Journ. of Med. Sci.,’ July, 1854.--_Farre, A._, “On the Larva of
_Anthomyia canalicularis_,” ‘Micr. Journ. and Struct. Rec.,’ 1841,
p. 129, and in ‘Trans. of Micr. Soc. of Lond.,’ orig. ser., p. 51,
1844.--_Figuer_, in ‘The Insect World’ (good figs.), Janson’s edit.,
1869.--_Furlonge_, “Anat. of Pulex,” in the ‘Journ. of the Queckett
Club,’ vol. iii.--_Geer, De_, ‘Mémoires pour servir à l’Histoire des
Insectes,’ 1773.--_Gervais_ (see Van Beneden).--_Hill_, “Account of
the Larva of a supposed _Œstrus hominis_, or Gad-fly, which deposits
its Eggs in the bodies of the human species, with particulars of a
Case,” ‘Edin. New. Phil. Journ.,’ vol. xxii, p. 284, 1830.--_Hilaire_
(see St Hilaire).--_Hope_, “Tables of Cases of (spurious) Intestinal
Worms,” ‘Lond. Med. Gaz.,’ 1837-38.--_Hoppe_, “Case of Larvæ of
Insects (_Musca stabulans_) passed by Stool,” from ‘Bibl. für Läger,’
in ‘Med.-Chir. Rev.,’ 1842.--_Hopper, R. S._, “Insects (Stratiomis)
voided with Urine,” edit. note in ‘Micr. Journ. and Struct. Rev.,’ p.
160, 1841.--_Joly_, ‘Recherches sur les Œstrides en général,’ &c.,
Lyons, 1846.--_Keferstein_, ‘Sur l’Oistros,’ Isis, 1827.--_Kirby_ (and
_Spence_), ‘Introd. to Entomology,’ 7th edit., 1856.--_Knox, M._,
“Maggots, the larvæ of the Bluebottle Fly, in Syphilitic Ulceration
of the Throat,” ‘Lancet,’ Oct. 6, 1877, p. 514.--_Lahory, B. T. C._,
“On _Peenash_, or Worms in the Nose,” ‘Ind. Ann. of Med. Sci.,’ 1855,
and ‘Edin. Med. Journ.,’ 1857.--_Leach_, “Œstridæ,” in ‘Wernerian
Trans.,’ 1817.--_Leidy_, in ‘Proc. Phil. Acad. Nat. Sci.,’ 1859, p.
7.--_Maclean_, “On the Oistros,” ‘Linn. Trans.,’ vol. xiv, 1824, and in
‘Zool. Journ.,’ vol. i and iv.--_Metaxa_, “Vom Œstrus (u. s. w.),” in
‘Neuen Nord. Beitr.,’ Bd. i, and in ‘Mém. de Zool. Med.,’ Rome, 1835
(quoted by Westwood).--_Moquin-Tandon_, ‘Med. Zool.’ (l. c., Bibl. No.
38).--_Newport_, art. “Insecta,” ‘Todd’s Cyclop.,’ 1839.--_Rustomjee,
B._, “Case of Worms in the Nose, or ‘Peenash,’” in ‘App. to Bomb. Med.
and Phys. Soc. Trans.,’ No. vii, new ser., p. 21, 1861; see also Lahory,
on ‘Peenash.’--_Saint-Hilaire_, “Sur l’Œstre chez l’homme,” in ‘Ann.
Soc. Ent. de France,’ 1833.--_Say_, “Brick’s Case,” in ‘Trans. Acad.
Nat. Sci. Phil.,’ vol. ii.--_Sells_, in ‘Trans. Entom. Soc. Lond.;’ see
also Lemprière’s ‘Diseases of the Army in Jamaica,’ vol. ii.--_Stockett,
T. H._, “An account of a Headache cured by the discharge of a Worm (?)
from the Nose,” ‘Med. Com.,’ vol. xix, p. 157, 1794, and in ‘Trans.
Coll. of Phys. Phil.,’ vol. i, part i, p. 181, 1793.--_Stroop, St J._,
“Œstrus,” in ‘Amer. Naturalist,’ vol. vii, p. 437.--_Tanner_, “On Lice,”
in his ‘Pract. of Med.,’ vol. ii, p. 429, 6th edit., 1869.--_Westwood_,
in his ‘Classification of Insects,’ vol. ii, 1840.--_Wohlfart_ (quoted
by Moquin-Tandon).--_Yule_, “Case of Larvæ of Insects in the Human
Stomach,” ‘Edin. Phil. Journ.,’ and ‘Lond. Med. Repos.,’ 1825.


SECTION IV.--PART VI.--PROTOZOA (Psorospermiæ, Gregarinidæ, &c.).

The scope of this work does not demand that I should comprise within
its limits any vegetable parasites; nevertheless, I must needs refer,
however briefly, to certain confervoid and sarcodic organisms, which,
for the most part, lie on the borderland of the animal and vegetable
kingdoms. Professor Cohn regards the bacteria as allied to the
Oscillitoriaceæ. He puts them in his order _Schizosporeæ_. It is of
little moment, practically, where these protista forms are placed.
Unquestionably many of them are parasitic, as they live in the tissues,
fluids, and secretions of animal bodies, including man. Their presence
in cattle is associated with an anthracoid disease (charbon), whilst
in the human body they have been detected in connection with zymotic
affections. They have been found by Cohn, Sanderson, Klebs, Chauveau,
and others, either in the lymph of vaccine pustules, or in the miliary
eruptions of typhus fever. Professor Beale, who was one of the first to
observe these special organic particles in vaccine lymph, denies that
they are true Bacteria; and, indeed, he warmly disputes the inferences
that have generally been drawn from the fact of the presence of such
particles in lymph, blood, and other nutrient fluids. The best known
and defined forms are _Bacterium termo_ and _Bact. lineola_, which are
concerned in the production of putrefaction, _Bacillus anthracis_, found
in the blood of animals suffering from carbuncular disease, _Micrococcus
septicus_, found in typhus and pyæmia, _M. vaccinæ_ of cow pox lymph,
and _M. diphthericus_, in diphtheria. As regards their prevalence in
certain forms of relapsing fever, Sanderson states that Dr H. V. Carter,
of Bombay, examined the blood of 250 fever patients and found _spirilla_
in nearly every instance. From the independent observations of Pasteur,
Sanderson, Lister, Tyndall, Bastian, Eberth, Roberts, Davaine, and
many others, it seems clear that the Bacteria and their allies play an
important part in association with certain morbid states. However, as
regards the etiology of the maladies in which these organisms are found,
it is perhaps too early to speak with absolute confidence. The subject
cannot be dealt with here; moreover, it is outside the range of my
personal investigations.

Passing to those protozoa which, although retaining some vegetable
affinities, are more or less distinctively animal, I notice the obscure
organisms termed psorosperms. In dealing with these I shall treat of the
forms that infest both man and animals, confining my remarks to such as
happen to have come under my own observation.

In the year 1865 the public were thoroughly roused to a sense of danger
arising from the consumption of meat. The panic originated with the
outbreaks of trichiniasis in Germany. During the excitement which
subsequently prevailed at the time of the rinderpest, all sorts of
erroneous notions took possession of the popular mind, and the errors
were stimulated by writers ignorant of helminthology. In January,
1866, I published a few observations, the purport of which was to
show that certain microscopic organisms found in animals dying from
cattle plague were harmless “parasitic Protozoa,” possessing more
or less striking vegetable affinities. About a week previously some
interesting researches on these so-called cattle-plague bodies had been
published by Dr Beale. Those who first saw these bodies thought they
had stumbled upon organisms new to science. I showed that similar or
analogous organisms were to be met with in a great variety of animals,
and likewise in the human body. They had been called worm-nodules,
worm-nests, egg-sacs, eggs of the common fluke, young “measles,”
corpuscles produced by muscular degeneration, psorospermiæ, stages of
growth of gregarinæ, amœboid bodies, and so forth. In so far as the
higher animals were concerned, Dujardin was the first to describe them.
He found these organisms in a mole. This animal, however, having been
fed upon earth-worms known to harbour such parasites, there was no
difficulty in accounting for the source of the psorosperms.

In 1853 Hessling discovered psorospermial sacs in the muscular substance
of the heart, not only of the ox, but also of the sheep and roe. By him
they were regarded as evidences of muscular degeneration. About ten
years previously Miescher found similar bodies in the muscles of the
mouse.

In 1857 Rainey described similar structures taken from the flesh of
swine; and, in his memoir, he went so far as to maintain that these
bodies were early stages of development of the common pork-measle.
In the year 1858 Gubler wrote an important paper on this subject, in
which he related a case where twenty cysts existed in the human liver.
The cysts were of great size, mostly as large as a hen’s egg, one of
them being some six inches in diameter. Naturally, the largest had
been diagnosed as an ordinary hydatid. However, on evacuating their
contents (post mortem), they were found to harbor enormous quantities
of minute corpuscles strictly analogous to those usually obtained
from psorospermial sacs. Gubler believed he had stumbled upon masses
of eggs of _Distoma hepaticum_, but in this he erred. Shortly after
Gubler’s discovery similar bodies from the human liver were described
by Virchow; and in 1862, the subject was followed up by Dr Dressler,
of Prague. Dressler found in the human liver a number of pea-shaped
bodies, the milky contents (_breisubstanz_) of which displayed a
multitude of the characteristic corpuscular elements referred to. These
particles, already considered as equivalent to, if not identical with,
the so-called pseudo-navicellæ of gregarinæ, were soon encountered by a
variety of independent observers. Thus, Leuckart noticed these bodies in
various animals; but with caution remarked:--“Concerning the nature of
these formations I will not decide. To be candid, however, it appears
to me to be in no way made out whether the psorospermiæ are to be
considered as the result of a special animal development, whether they,
like pseudo-navicellæ, are the nuclei of gregariniform productions, or
whether they are the final products of pathological metamorphosis.”
Leuckart found these organisms in the intestines of a trichinised dog,
also in a sheep and pig fed with Trichinæ. He also found them in the
muscles of another pig fed with psorosperms, and likewise in the liver
of various rabbits. He remarks that in swine these parasites are more
abundant than measles. They were present in five of eighteen pigs, and
also in two out of four sheep, whose flesh was especially examined.
The observations of Lindemann at Nischney-Novgorod are particularly
interesting. This medical officer discovered psorospermial sacs attached
to the hair of a girl who was being treated in hospital for chlorosis.
The sacs in question bore close resemblance to the bodies which we found
in abundance in diseased and healthy cattle. It would further appear,
from Lindemann’s observations, that the affection is not very uncommon
amongst the Russian peasants.

In connection with and attached to the same parasitically affected
hairs Lindemann also noticed several movable gregarinæ; and partly
from this circumstance he was led to believe in the existence of a
genetic relation subsisting between the two kinds of bodies. He further
expressed his conviction that the people contracted the disease by
washing themselves with water in which gregarinæ abounded. Lindemann
moreover refers to Lebert as having noticed similar parasites in a case
of favus, and concludes that these organisms are of a vegetable nature.
His opinion, though not shared by the majority of parasitologists, is
nevertheless supported by the views of Robin, Leydig, and others. Of
still higher interest are the observations of Lindemann respecting the
occurrence of psorospermiæ in the capsule of the kidney of a hospital
patient who died with Bright’s disease. The sacs in this case were
remarkably small; nevertheless their corpuscular contents indicated
their true nature. The pseudo-navicellæ measured only 1/5000″ in
diameter. Amongst other contributions of interest I may refer to those
of Dufour, J. Müller, Creplin, Kölliker, Keferstein, Stein, Drummond,
Lieberkühn, and E. Ray Lankester. I doubt if the vegetable organisms
described by Prof. W. T. Gairdner can be referred to this group of
parasites. At all events, by whatever name these spurious entozoa are
called, they were first discovered by Dufour in insects, by Müller in
fishes, by Miescher in the mouse, by Dujardin in the mole, by Hessling
in the larger quadrupeds, and by Gubler in man. The results of my own
examinations may be briefly re-stated. In the flesh of cattle I found
psorospermial sacs varying from 1/120″ to 1/12″ in length, and in that
of sheep from 1/220″ to 1/80″. The bodies were enclosed in well-defined
transparent envelopes, and their contents exhibited indications of
segmentation. In some specimens the segments displayed themselves as
a complete cell-formation, the contents of each cell being uniformly
granular. Under the 1/4″ objective the contained granules were clearly
visible, and on rupturing the sac their peculiar characters were at
once manifest, each granule or corpuscle represented a pseudo-navicel,
all displaying a tolerably uniform size, averaging 1/2000″ in diameter.
Some of the corpuscles were round, others oval, several bluntly pointed
at one end, many curved and fusiform, not a few being almost reniform.
Highly refracting points or nucleoli were visible in their anterior.

Turning to the practical aspect of the subject, I remarked that these
bodies had nothing to do with the cattle plague. No one who carefully
examined the flesh of animals that had died of rinderpest had failed
to discover them; yet, in one or two instances they appear to have
escaped notice. When it is considered how long it takes us to examine
a few grains weight of muscle carefully, it is obvious that the body
of a large beast might contain many hundreds of these organisms
without our being able to detect their presence, except by a prolonged
investigation. In the few rinderpest beasts, portions of whose flesh I
submitted to the microscope, I should say there were not more than 100
of these bodies in one ounce of meat; but in the heart of a healthy
sheep (which I afterwards ate) I calculated there were about 1000
parasites to the ounce, and in the heart of a healthy bullock (which
likewise served me for a meal) their numbers were rather in excess of
those in the sheep. Altogether, at two meals, I could not have swallowed
less than 18,000 of these psorosperms. Consumers of beef, mutton, and
pork eat these bodies every day, but they take no harm because the
parasites in question are not true helminths. Fine healthy beef has
been returned to the butcher when it was as good as any other meat
in the market. I have examined various kinds of meat, such as veal,
pork, and mutton, but in none have I found so great an abundance of
psorosperms as in beef, which was, notwithstanding, perfectly healthy
and sound. I calculated that in one instance a single ounce of the
flesh contained upwards of 2000 parasites. There is practically no
limit to the extent of this kind of parasitism, and there is no organ
of the body in which psorosperms may not be found. Moreover, the forms
they display are exceedingly various. Psorosperms have been found by
Siedamagrotzky in the muscles of the horse, and not very long ago,
through the help of Professors Simonds and Axe, I had the opportunity
to examine some peculiar worm-like structures which occupied the mitral
valve of a horse. To the naked eye they looked like coiled nematodes,
but I was soon convinced that they formed a peculiar type of psorosperm.
A complete view of these bodies was a matter of great difficulty owing
to the delicate nature of their limiting membrane and to the confusion
of markings produced by the interlacing of the fibres of the chordæ
tendinea. At length, by spreading a portion of the membrane of the valve
over a large glass slide, and by allowing it to dry slowly, I found that
the vermiform body presented neither beginning nor end. The appearances
were curious and puzzling. The organism formed a flattened tube or sac,
almost uniform in width and variously twisted upon itself. From the main
tube there projected several hernia-like secondary loops or branches,
most of them presenting less than half of the thickness of the former.
These peculiarities, however, can hardly be understood without reference
to the original illustrations. That these secondary coils were not of
the nature of hernial protrusions was evident, not alone from the nature
of their contents, but also from the fact that they showed distinct
anastomoses. In fact, the parasite was a simple sac or bag with branches.

On puncturing the main tube with a fine needle a small quantity of
tenacious creamy fluid made its escape. This, under Ross’s 1/4-inch
lens, resolved itself into a few excessively delicate sarcode globules
surrounded by fine granules. The granular matter displayed a tendency
to collect itself in the form of oval masses without showing any trace
of a limiting border. One of these masses, measuring 1/250″ in length,
I examined under a Wasserlein-objective, when I further ascertained
that the elementary particles or granules were uniformly oval in shape,
rather highly refractive, their size scarcely exceeding 1/8000″ in
diameter. The sarcode corpuscles, on the other hand, were of different
sizes, ranging between 1/3000″ and 1/1600″ in diameter.

From the facts thus elicited, negative as they were in respect of
helminthic structure, I could see no escape from the conclusion that
we had to deal with a new form of psorospermial bag, whose granular
contents consisted of excessively minute pseudo-navicellæ. In the centre
of the largest hernia-like loop there was a clear oval disk, which at
first brought to my mind the nucleus of _Monocystis_ infesting the
earth-worm, but it was merely a vacuole.

The case recorded by Gubler reminds me of another remarkable instance
of psorospermial cysts, in this case associated with true hydatids. In
1873 Dr Whittell sent me particulars of a case in which the contents of
an hydatid of the liver (drawn off, during life) consisted of shreds of
a true hydatid, a few echinococcus-hooklets, together with multitudes of
spindle-shaped amœboid particles of excessive minuteness and delicacy.
The bodies, floating in a transparent fluid, formed a thick milky or
creamy fluid, resembling pus in appearance; but there was no trace of
pyæmia. Judging from Dr Whittell’s figures, he must also have found a
solitary microscopic nematoid hæmatozoon, the nature of which was not
clear to him. I believe it to have been a specimen of _Filaria sanguinis
hominis_. Be that as it may, the case is altogether unique and deserves
further elucidation.

As regards the higher forms of protozoa it must suffice to allude
to the _Cercomonas hominis_ of Davaine, found in the dejections of
cholera patients, to the _Cerc. urinarius_ of Hassal and _C. saltans_
of Ehrenberg, to the _Trichomonas vaginalis_ of Donné, detected in the
vaginal mucus, and to the _Balantidium coli_ of Claparède and Lachmann,
originally found by Malmsten in the human colon. The _Balantidium_, or
_Paramæcium coli_, has frequently been observed in the evacuations of
fever patients, and it has also been found by Dr Treille in patients
suffering from the Cochin-China diarrhœa. Monads have also been found
in the stomach and intestines of the hog and various other animals.
Infusorial parasites are particularly abundant in batrachians, the
_Bursariæ_ of frogs and toads being familiar to every helminthologist.

BIBLIOGRAPHY (No. 41).--_Arloing_ (and _Tripier_), in ‘Gaz.-hebd.,’
1873, p. 574 (quoted by Davaine).--_Balbiani_, ‘Compt. Rend. Soc.
Biol.,’ 1867, p. 103 (quoted by Davaine and Bastian).--_Bastian_,
“On the Nature of the so-called _Sarcina ventriculi_,” ‘Brit. Med.
Journ.,’ Feb. 3, 1872.--_Idem_, “On Heterogenesis in its relation to
certain Parasitic Diseases,” ‘Brit. Med. Journ.,’ Feb. 24 and April 20,
1872 (see part iv, p. 417, with figs. from Balbiani).--_Beale, L._,
“Entozoon-like bodies in Muscles,” in the ‘Microscope in Medicine,’
4th edit., p. 485, 1878.--_Idem_, “Bacterium Hypothesis of Contagium,”
_ibid._, pp. 313-321.--_Burnett, W. T._, “On Psorospermia, Mermithes,
&c.,” in a paper entitled ‘Reviews and Records in Anat. and Physiol.,’
in ‘Amer. Journ. of Sci. and Arts,’ vol. xviii, 2nd ser., p. 104,
1854.--_Carter, H. V._, “On Spirilla,” quoted by Sanderson in ‘Brit.
Med. Journ.,’ Nov. 17, 1877, p. 700.--_Cobbold_, “Remarks on Spurious
Entozoa found in Diseased and Healthy Cattle,” ‘Path. Soc. Trans.,’
vol. xvii, p. 452, 1866, and ‘Lancet,’ Jan. 27, 1866, p. 88; see also
Prof. J. Gamgee’s work on the ‘Cattle Plague.’--_Idem_, “On Worm-like
Organisms in the Mitral Valve of a Horse,” ‘Veterinarian,’ Sept.,
1877.--_Idem_, “On Psorospermiæ in the Eye of the Cod (Morrhua),”
‘Linnean Society’s Proc.,’ May, 1862, and in ‘Intellectual Observer,’
1862, p. 199.--_Cohn_, ‘Nova Acta,’ xxiv, s. 103 (quoted by Leuckart),
Bd. i, s. 139.--_Creplin_, ‘Wiegmann’s Archiv,’ 1842, s. 61.--_Davaine_,
l. c., 2nd edit., “Synops. xxi” (with bibliog. refs.), 1878.--_Donné_,
‘Cours de Microscopie,’ Paris, 1847, p. 157.--_Dressler_, quoted
by Leuckart, Bd. i, s. 141.--_Drummond_, ‘Edin. Phys. Rep.,’
1852,--_Dufour_, ‘Ann. des Sci. Nat.,’ 1837.--_Dujardin_, ‘Traité’
(l. c., see Bibl. No. 1).--_Eberth_, ‘Zur Kentniss Bacteritischer
Mykosen,’ 1872.--_Eimer_, ‘Ueber Psorospermien,’ 1870.--_Gairdner_,
‘Edin. Phys. Soc. Rep.,’ 1853.--_Gluge_, “Cysts in Sticklebacks,”
‘Bullet. Acad. Roy. des Sci. de Bruxelles,’ 1838.--_Gubler_, ‘Mem.
Soc. Biol.,’ 1859, p. 657, and in ‘Gaz. Méd.,’ 1858, p. 61.--_Harz, C.
O._, “Eine neue Mikrococcusform im lebenden Thierkörper,” ‘Deutsche
Zeitschrift für Thier-Medicin und vergleichende Pathologie,’ f. Novemb.,
1878.--_Hessling_, ‘Sieb. u. Köll. Zeitsch.,’ 1853, p. 196.--_Henle_,
‘Müller’s Archiv,’ 1845.--_Hollis, W. A._, “What is a Bacterium?”
repr. in the ‘Veterinarian,’ p. 205, 1875.--_Keferstein_, ‘Götling.
gelehrte Anzeigen,’ 1862.--_Kloss_, ‘Ueber Parasiten (u. s. w.)’ (quoted
by Davaine).--_Knoch_, ‘Journ. de Russ. Kriegs. dep.,’ Bd. xcv, 1866
(quoted by Leuckart and by Davaine).--_Kölliker_, in ‘Zeitsch.’ (by
Sieb. and Köll.), 1848-49.--_Lambl_, ‘Prager Vierteljahrschrift,’
1859.--_Lankester, E. R._, “Recent Researches on Bacteria (with copious
references),” ‘Quart. Journ. Micr. Science,’ Oct., 1878.--_Lebert_,
‘Phys. Pathologique’ (quoted by Leuckart).--_Leidy_, “Gregarina,”
‘Amer. Phil. Trans.,’ 1851.--_Leisering_, “Bericht (u. s. w.),” in
‘Sachsen,’ 1865.--_Leuckart_, l. c., Bd. i, s. 135 and 740, and Bd.
ii, s. 842 _et seq._--_Leydig_, ‘Müller’s Archiv,’ 1851, s. 221, in
‘Micr. Journ.,’ 1853, p. 206, and in ‘Arch. f. Anat. und Phys.,’ 1863,
s. 191.--_Lieberkühn_, ‘Müller’s Arch.,’ 1854.--_Lindemann_, ‘Bullet.
Soc. imp. des Naturalistes de Moscow,’ 1863, and in ‘Gaz. Méd. de
Paris,’ 1870, p. 86.--_Lister, J._, “Natural History of Bacteria,”
‘Micr. Journ.,’ Oct, 1873.--_Malmsten_, “_Paramæcium coli_” (quoted
by Davaine, l. c., 2nd edit., p. 67).--_Miescher_ (quoted by Leuckart
and Siebold).--_Müller_, ‘Archiv,’ 1841, s. 477.--_Rainey_, ‘Phil.
Trans.,’ 1857.--_Rayer_, “Singulière éruption sur un véron (Cyprinus),”
‘Arch. de Méd. Comparée,’ Paris, 1842 (quoted by Davaine).--_Rivolta_,
“Psorospermi, &c.,” trans. in ‘Journ. des Vét. du Midi,’ 1869, pp. 445
and 521.--_Robin_, ‘Les Végét. Paras.,’ 2nd edit., p. 291.--_Sanderson_,
in ‘Privy Council Reports,’ 1874.--_Siedamagrotzky_, in ‘Recueil de Méd.
Vét.,’ 1872, p. 460.--_Stein_, in ‘Müller’s Arch.,’ 1848, and ‘Ann.
Nat. Hist.,’ 1850.--_Idem_, “Abhandl. d. k. Böhmischen Gesellsch.,”
x, s. 69, oder Lotos, 1859, s. 57 (quoted by Leuckart, Bd. i, s.
151).--_Steinberg_, ‘Walter’s Zeitschr. f. die moderne Medicin,’ 1862,
and in Leuckart, Bd. ii, s. 844.--_Stieda_, ‘Arch. f. pathol. anat.,’
Bd. xxxv, and in Leuckart, Bd. ii, s. 846.--_Suriray_, “Sur quelques
parasites du lombric,” ‘Ann. des. Sci. Nat.,’ 1836.--_Virchow_,
“Zur Keutniss der Wurmknoten,” ‘Arch. f. Anat. u. Phys.,’ xviii, s.
523.--_Vogel_, ‘Path. Anat.,’ i, s. 404.--_Waldenburg_, “Psorospermien,”
in ‘Arch. f. Path. Anat.,’ s. 435, 1867.--_Windbladh_, also
_Wising_, ‘On _Balantidium coli_’ (quoted by Leuckart, Bd. ii, s.
846-847).--_Winkler_ (see _Leisering_).

APPENDIX.--On various occasions I have dwelt upon the necessity of
acquiring accurate information respecting the degree of mortality due to
parasites, and in the present volume (p. 124) I have referred to the
defective evidences supplied by the returns of the Registrar-General
in respect of the echinococcus disease. My object is not to cast blame
upon those whose duty it is to publish the returns, but rather to call
attention to the advantages that would follow if the Registrar-General
were supplied with full and accurate information on this head.

Through the courtesy of Mr Noel A. Humphreys I have been furnished
with the following official statement of the number of _Deaths from
Worms_ in England and Wales, as recorded in the Annual Reports of the
Registrar-General throughout a decade of years:

  +--------------+----+----+----+----+----+----+----+----+----+----+
  |              |1868|1869|1870|1871|1872|1873|1874|1875|1876|1877|
  +--------------+----+----+----+----+----+----+----+----+----+----+
  |Total         | 172| 148| 151| 160| 154| 183| 188| 227| 204| 225|
  | including--  +----+----+----+----+----+----+----+----+----+----+
  |Porrigo       | 15 | 13 |  9 |  9 |  9 | 14 |  5 | 16 |  7 | 13 |
  |Scabies       |  6 |  2 |  7 |  1 |  4 |  2 | -- |  5 |  2 |  3 |
  |Tapeworm      |  8 |  3 |  6 |  3 |  5 |  3 |  5 |  5 |  2 |  6 |
  |Hydatids      | 20 | 20 | 33 | 37 | 41 | 34 | 29 | 43 | 31 | 51 |
  +--------------+----+----+----+----+----+----+----+----+----+----+

Considering the prodigious advances in helminthology during the last
half century, it is certainly remarkable that under the category of
“worms,” as a cause of death, only two kinds of true helminths should be
mentioned in the Registrar’s record. It will also strike the experienced
hospital and dispensary physician as somewhat remarkable that of the
two death-producing parasites above named one of them should be the
“tapeworm.” Now death from _Tænia_ is certainly a very rare occurrence,
although grave nervous symptoms are not unfrequently due to its presence
in man. Thus, I am inclined to regard the 46 reported instances of
death from this cause as a redundant estimate. On the other hand, I
am surprised to see no specified instances of death from lumbricoid
Ascarides, from Oxyurides, or even from Cysticerci, which now and then
take up their residence in the human brain.

As regards hydatids I believe the returns to be excessively deficient.
In place of an average of 34 deaths annually from this cause in the
United Kingdom I am of opinion that at least 400 deaths are due to
hydatids. This opinion and the data on which it was founded were
communicated by me twelve years ago to the Linnean Society, and I have
since become acquainted with facts which lead me to conclude that
my original estimate was very much below the mark. The post-mortem
registrar of one of our large hospitals has told me that of late years
as many as _ten_ deaths might be reckoned as annually due to hydatids in
their institution alone. At a smaller hospital I ascertained that the
average was about _four_. Obviously, if these estimates are correct,
the Registrar-General’s returns for the United Kingdom do not record
a tithe of the annual mortality due to hydatids. Perhaps another half
century will elapse before the truth of my deductions be confirmed by
the _official_ returns. For me, it must suffice to have pointed to the
desirability of securing more accurate records.

By a curious coincidence I had only just sent to press the sheet of this
work recording the statistics of hydatid disease in Australia (p. 123),
when a paper dealing with the same subject appeared in the ‘Lancet.’
I refer to the brief memoir of Dr David Thomas, of Adelaide, South
Australia, which was published on the 1st of March, 1879. Dr Thomas
writes as follows:

“It is well known that Australia presents an extraordinary prevalence
of hydatid disease, but, as far as I know, no definite statistics have
been published to illustrate the fact. Consequently, some months ago,
with the kind assistance of the Hon. W. Morgan, the present Chief
Secretary of South Australia, I endeavoured to procure reports from
the Governments of Victoria, New South Wales, Queensland, New Zealand,
Tasmania, and Western Australia, upon this question. Unfortunately, the
mode of registration of the causes of death in most of these colonies
was such as prevented the necessary replies being supplied. However, it
appears that in Tasmania no deaths were returned from this disease in
the ten years 1867-77. During the greater part of the same period no
separate classification of hydatid disease had been adopted in New South
Wales; but in 1875 four deaths were attributed to hydatids; in 1876,
eleven were so returned. In Victoria, however, the record of deaths from
this cause is far more complete, and I append a table based upon the
returns from that colony.

“One case, in which hydatid of the kidney was present, accompanied by
malignant disease of bladder, with stricture, was not returned as a case
of hydatid causing death.

“During the decade 1867-77, 2·5 per 1000 deaths were due to hydatid
disease. In 183 out of the 307 cases the liver was either solely or
conjointly with other organs the seat of disease. Holding the second
place in frequency come the lungs in 71 cases, _i.e._ 53 simple and 18
complicated.”

_Table of Deaths returned as being due to Hydatid Disease in the
Province of Victoria during the ten years 1867-77._

  Key to Column Headings:

  A = Year.                    I = Omentum.
  B = Liver.                   J = Ovary.
  C = Lungs and pleura.        K = Womb.(?)
  D = Brain and spinal cord.   L = Abdominal cavity.
  E = Heart and pericardium.   M = Situation not recorded.
  F = Kidney.                  N = More than one organ invaded.
  G = Spleen.                  O = Total annual deaths.
  H = Pancreas.                P = Totals

  +----+---+--+--+--+--+--+--+--+--+--+--+--+-------+----------+
  |  A | B | C| D| E| F| G| H| I| J| K| L| M|   N   |     O    |
  +----+---+--+--+--+--+--+--+--+--+--+--+--+-------+----------+
  |1868| 17| 5|  | 1|  |  |  |  |  |  | 2| 7| 1(_a_)|    33    |
  |1869|  6| 8| 1|  |  |  | 1|  |  |  | 2| 1| 3(_b_)|    22    |
  |1870| 10| 2| 1|  |  |  |  |  |  |  |  | 4|       |    17    |
  |1871|  4| 6| 1|  |  | 1|  |  |  | 1|  | 1| 1(_c_)|    15    |
  |1872| 19| 3| 1| 1|  |  |  |  |  |  | 2| 2| 1(_d_)|    29    |
  |1873| 17| 3| 2|  |  |  |  |  |  |  |  | 2| 5(_e_)|    29    |
  |1874| 21|10| 1|  |  |  | 1|  |  |  |  | 6| 2(_f_)|    41    |
  |1875| 29| 7|  | 2|  | 1|  |  | 1|  | 3| 2| 2(_g_)|    47    |
  |1876| 23| 1|  |  | 2|  |  |  |  |  | 1| 4| 5(_h_)|    36    |
  |1877| 20| 8|  | 1|  | 1|  | 1|  |  | 3| 2| 2(_i_)|    38    |
  +----+---+--+--+--+--+--+--+--+--+--+--+--+-------+----------+
  |  P |166|53| 7| 5| 2| 3| 2| 1| 1|1?|13|31|22     |   307    |
  |    |   |  |  |  |  |  |  |  |  |  |  |  |       |in 10 yrs.|
  +----+---+--+--+--+--+--+--+--+--+--+--+--+-------+----------+
  |(_a_) Lungs and kidneys.                                    |
  |(_b_) In two instances liver and lungs; in the third case   |
  |        liver and brain.                                    |
  |(_c_) Lungs and liver.                                      |
  |(_d_) Lungs and abdominal cavity.                           |
  |(_e_) In three cases liver and lungs; in one kidney and     |
  |        abdomen; in another liver, lungs, omentum           |
  |(_f_) Liver and lungs.                                      |
  |(_g_) One liver and lungs; the second case lungs and heart. |
  |(_h_) Three cases liver and lungs; one liver and kidney.    |
  |(_i_) Liver and lungs.                                      |
  +------------------------------------------------------------+

Such are the returns as recorded by Dr Thomas. If a comparison be
instituted between the data supplied by his decade-report and those
supplied by the decade-report which I have previously adduced (p. 123),
it will be seen that as regards the returns for the years 1868-72,
inclusive, both reports are in perfect agreement. Of still more interest
also is the circumstance that whilst, on the one hand, out of the total
of 307 deaths given in Dr Thomas’s table, 116 occurred during the first
semi-decade (_i.e._ from 1868 to 1872, inclusive), on the other hand,
no less than 181 deaths occurred during the second semi-decade (_i.e._
from 1873 to 1877, inclusive). This increase of 45 deaths during the
later semi-decade is very significant. It points either to the fact of
more careful returns having been made, or to an actual increase in the
fatality of the disorder. Possibly both the causes alluded to operated
to affect the returns. Be that as it may, Dr Thomas’s record is highly
instructive, and should stimulate the profession in England to supply
our Registrar-General with more precise data wherewith to construct his
annual reports.



                                BOOK II.

                         PARASITES OF ANIMALS.


In dealing with this division of the subject it will be impossible to
give more than the faintest outline. Let it be borne in mind that quite
as much information might be offered by me respecting the parasitism of
each of the commoner domestic animals as has been already advanced in
regard to the helminthism of man. That would by no means exhaust the
subject. Thus treated, a score of volumes, each equal in size to this,
would barely suffice to cover the whole ground of Parasitology; and
yet there are not wanting intelligent persons who regard Helminthology
as unworthy of their attention. These persons form a far too prevalent
type of educated ignorance, and unfortunately, it is just this class of
people who enjoy the prerogative of educational responsibility. Even
our metropolitan scientific institutions, expressly raised for the
purpose of diffusing useful knowledge, shrink from the revelations of
parasitism. Dominated by the miserable conception which judges that the
life-history of a worm cannot prove either interesting or instructive
to their audiences, they let slip the acquisition of scientific data,
a knowledge of which might enable them to combat successfully some of
the most terrible evils to which human flesh, in common with that of
animals, is heir.

In the following few pages many new points of departure for fresh
scientific work will inevitably be suggested; and if I only succeed in
conveying to the working student an adequate grasp of the whole subject,
especially in its bearings on the welfare of the higher domesticated
animals and man, I shall have accomplished all that I can reasonably
hope to do within the restricted limits of space at my command.



SECTION I (MAMMALIA).


In dealing with this class of hosts, exclusive of man, I shall notice
the entozoa of the various orders successively, taking the arrangement
which I employed many years since when writing the Mammalian Division of
a popular treatise called the ‘Museum of Natural History.’ The internal
parasites of those orders which happen to embrace important domesticated
animals will necessarily receive more attention than the others; some
notice of the ectozoa being likewise added.


PART I.--QUADRUMANA (Monkeys).

Monkeys are less afflicted with flukes than most animals. The
species known to me are _Distoma laciniatum_, found by Brongniart
in the pancreas of _Simia maimon_; _D. orbiculare_ and _Amphistoma
emarginatum_, from the intestines of _Cebus trivirgatus_; and
_Bilharzia hæmatobia_, a single specimen of which I obtained from
_Cercopithecus fuliginosus_. The monkeys of the Old World rarely harbor
full-grown tapeworms, but Cysticerci are abundant (_Cyst. tenuicollis_,
_C. cellulosa_, _C. pileatus_, _C. crispus_). The common hydatid
(_Echinococcus polymorphus_) has been found in many of the Simiæ, and
by myself in a Madagascar lemur (_L. macaco_). Dr Leidy also obtained
three hydatid cysts from a large monkey. On the last day of the year
1857 I obtained some polycephalous hydatids (_Cœnurus lemuris_) from
a ring-tailed lemur. They infested the liver, being more abundant in
the lungs. They occupied both sides of the chest. Loose and detached
specimens also existed in the cavity of the right pleura. Most of
those occupying the chest were connected to the pleura, forming
vesicular, semi-transparent masses, varying in size from a filbert
to a large walnut, many being united in bundles of much larger size.
One of these masses is here drawn (1, fig. 54). It consists of four
large Cœnuri, their combined pedicles forming a single stalk. A fifth
hour-glass-shaped rudimentary Cœnurus is also visible. Every Cœnurus
supports a variable number of lobules, each lobe supporting one or more
papillæ. Here and there the papillæ resemble chains of beads. No trace
of tapeworm heads could be seen, but under a half-inch objective glass,
I found some flat papillæ presenting oval depressions at the surface
(2, fig. 54). On examining some of the larger papillæ they were found
to consist of membranous layers folded one within the other. These
were carefully dissected and examined with the aid of needles, when
each one showed in the centre a well-formed tapeworm head with four
characteristic suckers, and a prominent rostellum supporting a double
coronet of hooks, thirty-two of the latter in all (3, fig. 54). The
hooks displayed a marked disparity of size and form. Each hook showed
conspicuous anterior and posterior root-processes, the larger set of
hooks individually measuring about 1/225″ and the smaller 1/330″ in
length (4, fig. 54). There were numerous calcareous corpuscles. The
interior of each vesicle was filled with a fluid, in which there were
no free scolices. On referring to my notes I find that the lemur had
arrived in England about four months previously.

[Illustration: FIG. 54.--_Cœnurus lemuris._ 1, Colony; 2, portion of the
ectocyst (enlarged); 3, scolex-head (magnified 40 diameters); 4, hooks
(magnified 260 diameters). Original.]

Larval cestodes do not appear to be common in the monkeys of the New
World (Cebidæ), nevertheless I found several Cysticerci in the liver of
_Macacus radiatus_ (Feb. 19th 1857), and a single specimen in the sooty
monkey (Dec. 4th 1857). They were wrongly described by me as Cercariæ.
The Cebidæ are largely infested with tapeworms (_Tænia megastoma_ and
_T. rugosa_). A species of Ligula (_L. reptans_) has likewise been found
beneath the skin of _Callithrix sciureus_ and in one of the marmosets
(_Hapale melanurus_). Perhaps the most common helminth infesting monkeys
is the nematode called _Filaria gracilis_. I have examined specimens
from the orang, the capuchin, and the spider monkey. This parasite
commonly occupies the abdomen, coiled beneath the peritoneum, or within
folds of the mesentery. It sometimes occurs beneath the skin, or within
the connective tissue of superficial muscles. The female worm has been
known to reach a length of five feet. In 1873 Mr Samuel Smith, of
Clifton, sent me five specimens of this worm. From one of the males,
which measured twenty inches in length, I procured some spermatozoa,
and found their long diameter to average 1/1400″. These corpuscles and
other structures, as well as the worm itself, are figured in my ‘Notes
on Entozoa’ quoted below. Next in frequency, perhaps, is the whipworm
(_Trichocephalus dispar_), which monkeys of all kinds harbor in common
with man. Besides these nematodes, _Physaloptera dilatata_ is found in
the stomach of American monkeys, and _Ascaris distans_ also (in the
large intestine of marmosets more particularly). This Ascaris has also
been found in _Cercopithecus fuliginosus_ and in _Simia sabæa_. A small
spiroptera is said to infest the walls of the stomach of _Simia maimon_.
To Dr Murie I am indebted for a large roundworm (_Ascaris lumbricoides_)
taken from the intestine of a chimpanzee (_Troglodytes niger_), and also
for a smaller nematode taken from a green mona-monkey (_Cercopithecus_).
This I have described and named _Ascaris cuspidata_. From the intestines
of a chacma (_Cynocephalus porcarius_) M. Schafhert procured sixteen
examples of a small strongyle (_Str. attenuatus_, Leidy).

The singular monkey known as _Tarsius spectrum_ is liable to be
attacked by a filaria (_F. lævis_), which is found beneath the skin.
At least two species of Echinorhynchus (_E. spirula_ and _E. elegans_)
are known to infest monkeys. I have carefully examined and figured _E.
elegans_ in the ‘Zoological Society’s Proceedings,’ from specimens
supplied to me by Dr Murie. They had been obtained from a pinche monkey
(_Hapale œdipus_) from New Granada. I am under the impression that
Diesing’s original description of this parasite is the only one that
exists. I have gone over his numerous memoirs contributed to the Vienna
Academy, but can find nothing beyond the specific characters given
in his ‘Systema.’ All the specimens in the Vienna Museum, whence his
description is taken, were collected by Natterer. They were procured
from the marakina (_Midas rosalia_), from two other true marmosets
(_Hapale ursula_ and _H. chrysoleuca_), and from a squirrel monkey
or tee-tee (_Callithrix sciureus_). In the monkey which died at the
Zoological Society’s Gardens the cause of death was not clearly due to
the parasites; nevertheless, the mucous layer of the intestine, to which
the entozoa were attached, showed deep conical pits or depressions at
the spots where the worms had anchored themselves. During the perfect
retraction of the proboscis of this Echinorhynchus the centre is
represented by a wide opening which communicates with a cavity beneath.
The end of the neck thus forms a sort of collar, or rosette, made up of
rays arranged like the spokes of a wheel. When the proboscis is exserted
this collar is more or less convex, but it becomes slightly concave when
the proboscis is retracted. Diesing recognised twenty-four rays; they
probably vary from that number up to twenty-eight, at least I counted
twenty-seven in my specimens. During exsertion the proboscis forms a
nipple-like projection. According to Diesing it supports three rows of
hooks, but I certainly saw four rows. When separately magnified these
hooks present very different appearances as to size and contour. These
variations I believe to be due to growth. The largest hooks measured
about 1/200″ in length.

As regards insect parasites, it is well known that monkeys are largely
infested by fleas, but the species have not been much studied. The
same may be said of their mites (_Acaridæ_). A species of Pentastoma
(_P. tornatum_, Creplin) has been found occupying little cysts of the
peritoneum and omentum in _Simia maimon_ and _S. cynomulgus_. Under a
synonym (_Linguatula Diesingii_) it has been very fully described by Van
Beneden. Another species (_P. subcylindricum_) has been found attached
to the lungs and liver of a marmoset (_Hapale chrysopygus_). Dr Leidy
found five specimens of _P. euryzonum_ in cysts on the subperitoneal
surface of the liver of _Cynocephalus porcarius_. Leuckart believes that
Dr George Harley’s _P. polyzonum_ is the adult state of _P. euryzonum_,
and that _P. subcylindricum_ is the larva of _P. proboscideum_, found in
_Boa constrictor_ and other serpents.

BIBLIOGRAPHY (No. 42).--_Beneden_ (see Van Beneden).--_Cobbold_, “On
_Filaria gracilis_ and _Ascaris cuspidata_,” in ‘Zool. Soc. Proc.,’
Feb. 3, 1874, p. 124.--_Idem_, “List of Entozoa, including Pentastomes,
obtained from Animals dying at the Menagerie in 1857-60 inclusive,”
‘Proc. Zool. Soc.,’ 1861.--_Idem_, ‘Entozoa,’ p. 119.--_Idem_, “On
Parasite-Larvæ (Cœnurus and Echinococcus of the Lemur),” ‘Intell.
Observer,’ vol. iii, pp. 86-96.--_Idem_, “Bilharzia from Cercopithecus,”
in ‘Synops. of Distomidæ,’ ‘Proc. Linn. Soc.,’ 1860, Zool. Div., pt. v,
p. 31, and in “Parasites from Zool. Gardens.,” in ‘Intell. Obs.,’ June,
1862, p. 352.--_Idem_, “On _Echinorh. elegans_,” ‘Proc. Zool. Soc.,’
1876, in ‘Notes on Entozoa,’ pt. iii, plate xvi, p. 202.--_Creplin_,
“On _P. tornatum_,” ‘Troschel’s Arch.,’ 1849, s. 54.--_Idem_, “_F.
gracilis_,” in ‘Wiegm. Arch.,’ 1851, s. 270.--_Diesing_, ‘Syst.,’ l. c.,
s. 611, and in ‘Sitzb. d. k. Akad.,’ 1854, s. 598.--_Harley, G._, in
‘Proc. Zool. Soc.,’ 1857, p. 12.--_Leidy, J._, “On Pentastoma,” ‘Proc.
Phil. Acad. Nat. Sci.,’ 1850, p. 97.--_Idem_, ‘Hydatids,’ l. c., 1856,
p. 46.--_Idem_, ‘_Strong. atten._,’ l. c., p. 54.--_Leuckart_, ‘Bau
und Entwicklungsgeschichte der Pentastomen,’ 1860, “_P. polyzonum_,”
‘Synops.,’ s. 153.--_Molin_, “On _F. gracilis_,” in ‘Sitzungsb. d. k.
Akad. d. Wissensch.,’ 1858, Bd. xxviii, s. 376.--_Schneider_, ‘Monag.
der Nem.,’ 1866, “_F. gracilis_,” s. 87.--_Smith, S._, “On _F. gracilis_
found in connection with the Great Omentum of a Spider-monkey,”
‘Proc. of Bristol Naturalists’ Soc.,’ vol. i, 1873.--_Van Beneden_,
“_Ling. Diesingii_,” in ‘Mém. Acad. Belgique,’ vol. xxiii, ‘Recherches
sur l’organisation et le dévélopment des Linguatules, suivies de la
description d’une espèce nouvelle provenant d’un Mandrill,’ 1849.


PART II (CHEIROPTERA).

Until lately not very much attention had been paid to the parasites
of bats, probably on account of the insignificance of the hosts.
However, whilst Dr Dobson has recently been extending the subject of
Cheiropterology, Prof. van Beneden has added largely to our knowledge
of the parasites of bats. In his beautiful memoir, the Belgian
helminthologist asks whether the parasites quit their hosts during the
period of hybernation, and then proceeds to answer that question in
the negative. Should the bats die, the parasites of necessity share
the same fate. It would appear, however, that the spermatozoa of
the worms are capable of surviving their parents for a fortnight or
even longer. Flukes abound; the most common species (_Distoma lima_)
infesting the pipistrelle, noctule, mouse-colored bat, Natterer’s bat,
parti-colored bat, Daubenton’s bat, whiskered bat, and the greater and
lesser horseshoe bats. Almost as abundant is the _Distoma chilostomum_
found in most of these bats, and also in Leisler’s or the hairy-armed
bat. Dujardin’s _D. heteroporum_ is a synonym of the species. Schreber’s
_Monostomum_ is probably identical with Van Beneden’s _Distoma ascidia_.
This fluke he found in _Vespertilio marinus_, _V. dasycnemus_, _V.
Daubentonii_, _V. emarginatus_, _V. serotinus_, _V. mystacinus_, _V.
pipistrellus_, _V. auritus_, and in _Rhinolophus hippocrepis_. Another
species, distinguished from _D. ascidia_ by its large ventral sucker,
has been found in great numbers in the noctule (_D. ascidioïdes_, Van
Beneden). The cestodes of bats are not numerous. The best known species
(_Tænia obtusata_) has been found in the serotine, in the mouse-colored
bat, and in _Vespertilio lasiurus_. Another species (_T. decipiens_)
occurs in _Molossus perotis_, and _Chylonycteris rubiginosus_, and a
scolex, forming the type of a new genus and species (_Milina grisea_,
Van Ben.) has been obtained by hundreds in the intestines of _Vesp.
murinus_ and _V. serotinus_. Of nematodes we have _Ophiostomum
mucronatum_, Rud., and _Oph. spinosum_, W.-Suhm (from _Vespertilio
mystacinus_)., _Trichosomum speciosum_, Van Ben., _Strongylus tipula_,
Van Ben., _Strongylacantha glycyrrhiza_, Van Ben., _Litosoma filaria_,
Van Ben., _Ascarops minuta_, Van Ben., and one or two sexually-immature
forms, either found loose in the tissues or occupying cysts. The
Acanthocephala are not known to infest bats. Respecting insects,
one family (Nycteribiidæ) is exclusively parasitic upon bats. They
resemble the forest-flies in their habits. The best known species is
_Nycteribia Latreillei_, but several others (_N. biarticulata_ and _N.
Sykesii_, Westw.) have been described. One or more of the Brazilian
bats are infested by _Lipoptena phyllostomatis_, Nitsch, and Westwood
has obtained several allied forms of _Hipposcidæ_ (of the genus
_Strebla_), also from bats. As regards the true Arachnidans (mites and
ticks), Van Beneden enumerates _Ixodes lividus_, Van Ben., _Pteroptus
vespertilionis_ and _P. arcuatus_, Koch, _Otonissus aurantiacus_ and
_Cerathophyllus octactenus_, both of Kolenati, and _Caris elliptica_.

BIBLIOGRAPHY (No. 43).--_Audouin_, ‘Ann. des Sci. Nat.,’ xxv.--_Beneden,
P. J. van_, “Les Parasites des Chauves-souris de Belgique,” fr. vol.
xl of the ‘Mém. de l’Acad.,’ 1873.--_Diesing_, ‘Syst. Helm.,’ ii, p.
530.--_Dufour_, ‘Ann. des Sci. Nat.,’ 1831.--_Dujardin_, l. c., p.
437.--_Kolenati_, ‘Die Parasiten der Chiropteren,’ 1857.--_Latreille_,
art. “Nycteribie,” in ‘Nouv. Dict. d’Inst. nat.’--_Müller_, ‘Zool.
Danica,’ ii, p. 43, “_Fasciola vesp._ (syn. _Dist. lima_).”--_Perty_,
“Lipoptena,” ‘Del. an. art. Brasil’ (quoted by Westwood).--_Rudolphi_,
‘Synops.,’ p. 117.--_Westwood_, “Mém.,” in ‘Zool. Soc. Trans.,’
1835.--_Idem_, ‘Modern Classif. of Insects,’ vol. ii, p. 585,
1840.--_Willemoes-Suhm, R. V._, “Helminthologische Notizen,” iii,
‘Zeitsch. f. wiss. Zool.,’ 1873.


PART III (INSECTIVORA).

The entozoa of insectivorous mammals, though sufficiently numerous, are
not important practically. The common hedgehog (_Erinaceus europæus_)
is infested by four flukes (_Distoma pusillum_, _D. trigonocephalum_,
_D. caudatum_, _D. linguæforme_), and also by three thorn-headed worms
(_Echinorhynchus napæformis_, _E. amphipachus_, and _E. major_). Two
tapeworms are also known (_Tænia compacta_ and _T. tripunctata_). More
attention has been paid to the round worms. A species of strongyle (_S.
striatus_) infests the lungs, the male being readily distinguished
by its nearly round hood. A second species of strongyle has been
mentioned by Diesing, but it is more than doubtful. The lungs are
also infested by a small trichosome (_Eucoleus tenuis_ of Dujardin);
another species of the genus (_Trich. exiguum_) infesting the stomach
and small intestine. As the _Trichina spiralis_ has been repeatedly
reared by myself and others in the hedgehog, the little flesh-worm
must also be noticed in this place. _Physaloptera clausa_ occupies the
stomach, and a minute Ascaris (_A. pusilla_) is found in cysts of the
peritoneum. According to Wedl, the intestine of the Egyptian hedgehog
(_Erinaceus auritus_) is infested by another worm, which he calls
_Pterygodermatitis plagiostoma_. This is allied to Froelich’s genus
_Rictularia_. As regards the mole (_Talpa europæa_), two flukes have
been described (_Distomum flexuosum_ and _Monostomum ocreatum_), also
two round worms, namely, _Ascaris incisa_, occupying the peritoneum, and
_Spiroptera strumosa_ in the cavity of the stomach. Dr Schneider places
the latter with the Filariæ. A little tapeworm (_Tænia bacillaris_)
infests the small intestines, and a larval cestode occupies the liver
and subcutaneous connective tissues. This is the well-known _Cysticercus
talpæ_, which Leuckart and others have referred to as being the
scolex or juvenile state of _Tænia tenuicollis_ infesting weasles
(_Mustelidæ_). The Cysticercus is also found in _Arvicola arvalis_.
In regard to the shrews, many species of fluke have been described as
occupying the intestines. In _Sorex araneus_ and _S. leucodon_, the
_Distoma migrans_; in _S. constrictus_, the _D. exasperatum_; in _S.
tetragonurus_, the _D. corrugatum_ and _D. rubens_; the last-named
fluke, with two others (_D. instabile_ and _D. truncatum_), being
also found in Daubenton’s shrew. The tapeworms are numerous--_Tænia
neglecta_, _T. furcata_, _T. uncinata_, _T. pistillum_, _T. tiara_, _T.
scalaris_, _T. scutigera_. With the exception of the last named, all
these forms occur in the common shrew. According to the investigations
of M. Villot the cysticercal stage of _T. pistillum_ is to be found in
the glow-worm (_Glomeris_). This scolex (_Staphylocystis micracanthus_,
Villot) multiplies by proliferation, and in this way the swallowing of
a single intermediate host may result in the formation of a hundred or
more tapeworms. Another species of Staphylocystis (_S. biliarius_) is
considered by Villot to be the larval source of _T. scutigera_ and _T.
scalaris_, which are perhaps identical species. A small Echinorhynchus
(_E. appendiculatus_), found in the intestines and also encysted in
the mesentery of the shrew, in like manner becomes transferred to the
stomach of the fox. The nematodes of shrews possess little interest.
In the common shrew the only species known are _Trichosoma splenaceum_
and an immature worm, whilst in _Sorex tetragonurus_ we have _T.
incrassatum_, occupying the tunica vaginalis of the testis, and
_Strongylus depressus_ in the intestines. Not many other insectivora
appear to have been studied in relation to their internal parasites.
A larval cestode has been noticed in the Russian musk rat (_Mygale_),
and also a tapeworm (_Tænia sphærocephala_) in the golden mole
(_Chrysochloris_). Several flukes and a tapeworm have been found in
the water-shrews (_Sorex fodiens_), but, so far as I am aware, nothing
has been done in connection with the parasites of the _Macroscelidinæ_,
of the Banxrangs (_Tupainæ_), or of the Tanecs (_Centites_) and their
allies. The entozoa of the star-nosed and shrew moles of North America
(_Condylura_ and _Scalops_) also deserve attention. From the last-named
genus (_S. canadensis_) Prof. Leidy obtained a single male spiroptera.
It occupied the stomach and was only half an inch in length.

BIBLIOGRAPHY (No. 44).--_Leidy_, “_S. scalopsis canadensis_,” ‘Proc.
Phil. Acad.,’ 1851, p. 156.--_Linstow_, “_D. cordatum_, Einige neue
Distomen (u. s. w.),” ‘Arch. für Anat.,’ 1873, s. 95.--_Molin_, ‘Una
Monografia del genere Physaloptera,’ Wien, 1860 (p. 7, “_P. clausa_,”
and p. 31, “_P. limbata_”).--_Idem_, ‘Nuovi myzelmintha,’ Wien, 1859, p.
10, Spec. No. 8.--_Idem_, ‘Una Monogr. del genere Spiroptera,’ Wien,
1860, p. 25, Spec. No. 22.--_Schneider_, ‘Monogr. der Nematoden,’
Berlin, 1866, s. 103, Spec. No. 39.--_Stieda_, in ‘Troschel’s Archiv,’
1862, “Description and figs. of _Tænia uncinata_ and _T. furcata_ of the
Shrew.”--_Thomson_, art. “Ovum,” in ‘Todd’s Cyclop. of Anat. and Phys.,’
contains figs. and description of _T. pistillum_ (from Dujardin),
vol. v, p. 28.--_Villot, A._, “On the Migrations and Metamorphoses
of the Tapeworms of the Shrews,” in ‘Ann. of Nat. Hist.,’ March,
1878, from ‘Comptes Rendus,’ Nov. 19, 1877, p. 971.--_Wedl, K._, “Zur
Helminthenfauna Ægyptens,” ‘Sitzungsb. d. math.-naturw. Classe’ (u. s.
w.), Bd. xliv, Abth. i, s. 464.


PART IV (CARNIVORA).

Notwithstanding the importance of the entozoa of this large section of
mammals, I must deal with them very summarily, emphasising my remarks
on the parasites of the dog and cat. Only a few of the ectozoa can be
noticed.

The bears are much infested by nematodes, the species being _Ascaris
transfuga_ and _Spiroptera_ (_Gongylonema_) _contorta_ of Molin. The
latter is found in the œsophagus. Immature round worms have also been
found in cysts. These were erroneously described as cestodes by Zeder
and Gmelin. The bear, however, is very liable to be infested by genuine
Cysticerci. Retzius found them in the muscles, and they are described
as examples of the ordinary hog-measle. The museum attached to Guy’s
Hospital contains the heart of a bear which is largely infested by
Cysticerci. A species of tapeworm has been found in the polar bear. The
coati (_Nasua narica_) is infested by _Ascaris brachyoptera_ in the
intestine, by Molin’s _Physaloptera semilanceolata_ from the stomach,
by _Echinorhynchus spirula_, _Tænia crassipora_, and _Ligula reptans_,
the latter occupying the muscles. A second species of Ascaris (_A.
alienata_) is described from _Nasua rufa_.

The racoons (_Procyon_) are infested by a species of pentastome (_P.
subcylindricum_), and Prof. Leidy has described a threadworm (_Filaria
insignis_) obtained from a cyst in the foot. The gluttons (_Gulo_) are
liable to be infested by an Ascaris, a Ligula, and by _Eustrongylus
gigas_. The giant strongyle also infests the coati (_Nasua_). The
skunk harbors _Tænia crassipora_. The Hunterian Museum contains four
specimens of _Strongylus cruciformis_ taken from a badger (_Meles_).
The otters are largely infested by flukes; _Distoma trigonocephalum_,
_D. incrassatum_, and _D. rude_ being found in _Lutra vulgaris_, _L.
solitaria_, and _L. braziliensis_, respectively, the latter also
harboring _Hemistoma clathratum_. Otters are likewise infested by
_Ligulæ_ and _Eustrongyli_. The weasels (_Mustelidæ_) are attacked by
a legion of entozoa, comprising flukes, tapeworms, round worms, and
thorn-headed worms; they are also liable to harbor many ectozoa, a large
tick (_Ixodes_) being especially troublesome.

[Illustration: FIG. 55.--_Strongylus gigas_, coiled within the kidney of
a coati. After Leuckart.]

Amongst the nematodes is Van Beneden’s _Filaroides mustelarum_, for
specimens of which I am indebted to Mr Wright Wilson. This is found in
the lungs, trachea, and in the frontal and nasal sinuses of the common
marten (_Mustela foina_), in which situations it causes absorption of
the cranial bones. This worm occurs also in the polecat (_M. putorius_),
in the common weasel (_M. vulgaris_), and in the pine-marten (_M.
martes_). The larvæ reside in frogs. Weasels are also very liable to
have their kidneys invaded by _Eustrongylus gigas_. A species of
Ascaris and a Trichosoma (_T. entomelas_) are not uncommon in the
intestines. In regard to the tapeworms, _Tænia tenuicollis_ infests the
polecat and the common weasel, and _T. intermedia_ the pine-marten.
The most common fluke of the weasel is _Distoma trigonocephalum_. This
infests the intestine, while _D. megastomum_ is found in the stomach.
The stoat or ermine (_M. erminea_) harbors _Strongylus patens_ and
_Tænia brevicollis_.

The parasites of the civets, ichneumons and their allies, (_Viverridæ_)
are of little importance. Many years ago I described a small fluke
(_Distoma compactum_) obtained from the lungs of the common Indian
ichneumon (_Viverra mungos_). It is figured in my ‘Entozoa,’ (p. 16).
Two species of tapeworm (_Tænia platydera_ and _T. genettæ_) have
been found in the common genet (_V. genettæ_), and also a round worm
(_Ascaris brachyoptera_). From another viverra (_V. senegalensis_)
Dujardin obtained a strongyloid worm (_Dochmius crassus_). A species
of mongoos (_Herpestes leucurus_) is likewise infested by tapeworms
(_Bothriocephalus folium_).

Comparatively speaking, very few entozoa infest the hyænas. In this
family I include the earth-wolf (_Proteles lalandi_). Some years back
Prof. Flower sent me a large number of delicate nematodes found loose
in the peritoneal cavity of this singular South African carnivore.
The worms themselves were so peculiar that I was compelled to form a
new genus for their reception (_Acanthocheilonema dracunculoides_).
From the intestines of the common _Hyæna striata_ Dr Lautner obtained
_Echinorhynchus gigas_.

The parasites of the wolf, jackal, and fox family (_Canidæ_) have
especial interest, as including those of the dog. I can, however, do
little more than mention the names of the various helminths of the dog,
and the sources whence they come. At the same time, I shall incidentally
refer to the wild canine animals that happen to harbor the same
parasites.

[Illustration: FIG. 56.--_Distoma conjunctum._ Eight parasites of the
natural size. Original.]

The flukes of the dog are few in number. Perhaps the most important is
_Distoma conjunctum_, originally discovered by myself in an American
fox (_Canis fulvus_) that died at the Zoological Gardens. Lewis, eleven
years afterwards, found it in the pariah dogs of India, where it is of
frequent occurrence. It infests the bile ducts. As already stated, Prof.
McConnell subsequently found this entozoon in man (1875), a second
instance being recorded later on (1878). Another species of canine
liver fluke has been described by Prof. Ercolani (_D. campanulatum_),
besides which there is the winged species occupying the small intestines
(_Holostoma alatum_). This latter is also found in _Canis azaræ_.

The tapeworms of the dog are not only numerous, but also particularly
injurious, alike to their bearers and to mankind. By experimental
research we have ascertained the sources of most of the _Tæniæ_. The
serrated species (_T. serrata_) is derived from _Cysticercus pisiformis_
infesting hares and rabbits. This is common in sporting animals, owing
to the careless practice of allowing gamekeepers and kennel masters to
throw the fresh viscera of the intermediate hosts to the dogs. I have
witnessed this stupid habit in the field. The cucumerine tapeworm (_T.
cucumerina_) is, by most observers, considered to be identical with
the _T. elliptica_ of the cat. I regard it as a variety. This delicate
species is excessively common and is now, through Melnikow’s discovery,
known to be derived from the louse of the dog (_Trichodectes latus_).
This circumstance affords a curious illustration of the fact that an
ultimate host may carry the intermediate host upon its back.

[Illustration: FIG. 57.--_Tænia cucumerina._ _a_, Strobile; _b_,
head (enlarged); _c_, proglottoid, showing the sexual orifices; _d_,
termination of the reproductive organs on one side. Magnified 60
diameters. Original.]

As regards the relative prevalence of these tapeworms in England, it
may be said that whilst _T. serrata_ occurs almost entirely in our
harriers, greyhounds, sheep-dogs, and lurchers (taught to “pick up”
hares), the _T. cucumerina_ is liable to infest any variety of dog,
and probably infests nearly 70 per cent. According to Krabbe the
prevalence of the last-named species is 57 per cent. in Iceland and
48 per cent. in Copenhagen, whereas the _T. serrata_ is almost absent
from those countries. The gid tapeworm (_T. cœnurus_) is derived from
the ordinary gid hydatid infesting the brains of sheep and lambs. The
polycephalous bladder-worm (_Cœnurus cerebralis_), so familiar to
agriculturists and veterinarians, is often confounded with the ordinary
hydatid infesting ruminants. Cœnuri infest the soft parts of rabbits,
but it remains to be shown whether they are the same species. Possibly
the _Cœnurus cuniculi_ is merely a variety. The gid tapeworm is not
very abundant in England. In Denmark it appears to be rare, occurring
in 1 per cent. only; but in Iceland Krabbe found it in 18 per cent. In
common with other helminthologists, I have frequently reared this and
the serrated species by worm feedings administered to dogs. The lettered
tapeworm (_T. litterata_) is very commonly spoken of as the _Tænia canis
lagopodis_. It was so named by Viborg, but I prefer the more distinctive
nomenclature of Batsch. We know nothing, for certain, respecting
the source of this entozoon. It is rare if not altogether wanting
in Denmark, but abundant in Iceland (21 per cent.). I have obtained
specimens from a cheetah (_Canis jubatus_) which died at the Zoological
Gardens, and Mr W. H. Jackson, of Oxford, found it in a cat. The worm is
certainly not confined to the Arctic fox (_C. lagopus._).

A well-known tapeworm infests the fox which has not yet been noticed in
the dog. This is the _Tænia crassiceps_, whose scolices (_Cysticercus
longicollis_) reside in the viscera and soft parts of field mice
and voles (_Arvicola arvalis_, _A. terrestris_, _A. amphibius_).
This relationship was pointed out by Leuckart. Another tapeworm (_T.
opuntioides_) mentioned by Rudolphi as occurring in the wolf, seems to
be of doubtful authenticity. A formidable and not uncommon tapeworm is
_Tænia marginata_. This large species occurs in at least 25 per cent. of
English dogs, whilst in Iceland its prevalence reaches 75 per cent. In
Denmark about 14 per cent. only.

It is well known that the larval or scolex stage (_Cysticercus
tenuicollis_) of the margined tapeworm resides in the sheep and dog. In
a feeding experiment with five examples of this bladder worm I reared
five strobiles of ten days’ growth. These immature tapeworms were each
one inch long. By far the most important tapeworm of the dog, however,
is the hydatid-forming species (_T. echinococcus_). This remarkable
entozoon is the sole cause of the terrible echinococcus disease, so
prevalent in Iceland and elsewhere. Experimental research, initiated by
von Siebold, has explained its origin; Van Beneden, Zenker, and others
have also experimented successfully. Rarely attaining a length of 1/3″,
the perfect strobile is made up of only three proglottides in addition
to the head, the lowermost segment being sexually mature. As hydatids
(_Echinococcus veterinorum_ or _E. hominis_) are found in a great
variety of animals as well as in man, and as these bearers form so many
kinds of intermediate hosts, it is easy to understand how readily dogs
and wolves may acquire the sexually-mature tapeworm. I am in possession
of hydatids from the liver of a clouded tiger (_Felis macroscelis_).
In England the _Tænia echinococcus_ is excessively rare, and has not
been seen in any dog which had not previously been subjected to a
feeding experiment. Mr Nettleship succeeded in rearing large numbers.
In Iceland, Krabbe found dogs to be infested to the extent of 28 per
cent., a proportion fully explaining the prevalence of hydatid disease
in that country. The remaining tapeworms of the dog belong to the genus
_Bothriocephalus_; of these, the broad tapeworm (_B. latus_) is best
known, because it infests man. Diesing has described a variety found
in the Pomeranian dog as a separate species (_Dibothrium serratum_).
The museum of the Royal Veterinary College contains a very perfect
specimen of _B. latus_ from an English dog, but the parasite is of rare
occurrence in this country. It is generally supposed that this tapeworm
is derived from the consumption of fish belonging to the salmon and
trout family, but Dr Fock, of Utrecht, thinks that the bleak (_Leuciscus
alburnus_) is the usual intermediate host. I have already discussed
this question at some length. Experimental proof is still wanting. In
addition to _B. latus_ the dog is liable to harbor _B. cordatus_, _B.
fuscus_, and also two varieties of the last-named species (_B. dubius_
and _B. reticulatus_, Krabbe). Taking the pit-headed tapeworms as a
whole, their prevalence in Iceland is not considerable, amounting to
about 5 per cent. only. Lastly, it may be mentioned that instances are
recorded of the occurrence of the hog-measle (_Cysticercus cellulosæ_)
in the dog. Though many have felt sceptical on this point, Gurlt’s
authority is not to be lightly set aside, confirmed, as it has been, I
believe, by MM. Mégnin and Leblanc.

Passing to the round worms it may be said that _Ascaris marginata_ is,
at the best, a mere variety of _A. mystax_ of the cat, with which
must also be placed _A. leptoptera_ of the lion and other felines.
The lateral appendages not only vary in breadth in these three forms,
but also in the specimens obtained from each host. I have encountered
examples in a dog, which measured more than six inches in length. The
worm is excessively common in England, occurring in probably not less
than 75 per cent., whilst in Denmark it occurs in about 24 per cent.
According to Krabbe it is rare in Iceland. Its presence is at all
times more or less injurious to the bearer, being a frequent cause
of sickness, colic, convulsive fits, and paralysis. Occasionally the
worms prove fatal to dogs by wandering into the trachea. At the Royal
Veterinary College, in 1864, a litter of six puppies, of only three
weeks growth, died rather suddenly in consequence of the presence of
these worms in the stomach and small intestines. So far back as the year
1684 Redi described round worms from the walls of the œsophagus of a
dog. These were afterwards noticed by various observers in tumours of
the mucous membrane of the stomach. Owing to their red color, derived
from the ingested blood of the host, the species was named _Spiroptera
sanguinolenta_. In 1867 I suggested that the minute Filariæ found by
Grube and Delafond in the blood of dogs would probably turn out to be
referable to this species. The researches of Lewis have proved that
this supposition was correct. To be sure, other nematoid hæmatozoa, of
microscopic dimensions, occur in the dog, but those described by Grube
and Delafond may be referred to _Spiroptera_. These authors estimated
their number in the canine host to vary from 11,000 to upwards of
200,000. In one instance Messrs Grube and Delafond found six worms
lodged in a clot occupying the right ventricle of the heart. Four were
females and two males. Although they were described as representing an
altogether new species, which they termed _Filaria papillosa hæmatica
canis domestici_, I think there can be little doubt that they were
examples of _Spiroptera sanguinolenta_ not fully grown. The writings
of Lewis abound with interesting details respecting the structure and
development of this worm, and as much may be said of the writings of
Manson and Welch concerning the cruel threadworm (_Filaria immitis_,
Leidy) occupying the right cavities of the heart. I was first made
acquainted with this entozoon in 1853, by examining specimens in the
possession of Prof. Hughes Bennett of Edinburgh; at which time also I
was put in possession of a valuable MS. (since lost) describing the
ravages of this entozoon in the dogs of China. I have since received
numerous verminiferous hearts both from China and Japan, and also
some heart-worms from Charleston, U. S., sent by Mr M’Innes. In a
recent communication, Dr Manson has spoken of this worm as if it were
comparatively harmless, but all the evidence I long ago received through
the late Mr Swinhoe, formerly H. B. M. Consul at Amoy, through Mr Dare’s
letters enclosing Dr Orton’s valuable observations (addressed to the
editor of the ‘Field’), through the lost MS. above alluded to, through
Dr Lamprey’s statements, and through many other sources, lead to the
very opposite conclusion. No doubt the canine hosts do for a time appear
to be little inconvenienced by their nematode guests, but sooner or
later the most distressing symptoms set in. As in Hoysted’s case (quoted
below) the convulsive spasms may occasion death in a few minutes, but
frequently they last for hours or days, with more or less prolonged
intervals of relief before the final struggle.

[Illustration: FIG. 58.--_Filaria immitis._ Tail of male. Enlarged.
Original.]

Some other filariform nematodes have been imperfectly described. Of
these, Gescheidt’s _Filaria oculi canini_ (_F. trispinulosa_, Diesing)
was probably a sexually-immature worm, and the same may be said of the
encysted worms found by Mr Mather in the mucous coat of the intestines
and in the liver ducts and acini (_Filaria hepatica_, Cobbold). Of
more interest is Leisering’s hæmatozoon (_Strongylus subulatus_).
These minute worms occupy the veins, the largest females not exceeding
1/12″ in length. They are viviparous, and thus form another source of
embryonic hæmatozoa. A single drop of infected venous blood commonly
carries from four to six mature worms. In this place may be mentioned
Dr Osler’s _Strongylus canis bronchialis_. The largest males measure
1/6″ and the females fully 1/4″. In the worms sent to me by Prof. Osler
I saw no evidence of strongyloid structure, and in his description he
avoids all mention of the presence of any caudal hood in the male. I
regard the worms as Filariæ (_F. Osleri_, Cobbold). Very great interest
attaches to them from the fact that they produce a destructive canine
epizoöty, resembling the ordinary “husk” or parasitic bronchitis of
calves, lambs, and other domesticated animals. The only other genuine
strongyle known to infest the dog is _Eustrongylus gigas_. This is a
very common parasite in wolves. I have already spoken of this parasite
at some length (Book I, p. 207), and can only further refer to the
recently published case by Mégnin (quoted below, and at full length in
my paper in the ‘Veterinarian’ for April, 1879). The Museum of the Royal
Veterinary College contains three fine examples of this worm coiled
within the kidney of a dog, or rather within the renal capsule, for
the substance of the organ is almost entirely wanting. These are from
Bickford’s case.

Amongst the many good “finds” made by Lewis in India, not the least
interesting is that appertaining to _Cheiracanthus robustus_. Lewis,
indeed, supposed that he had detected _Echinorhynchi_ in chestnut-sized
tumours of the walls of the stomach, but, as I pointed out at the time,
the parasites were entirely destitute of Acanthocephalous structure. As
is well known, this curious nematode infests various felines, such as
the wild cat, puma, and tiger. In addition to the above canine nematodes
we have the wrinkled threadworm (_Trichosoma plica_) infesting the
bladder. This is of much more frequent occurrence in the fox. In the
list _Trichina spiralis_ must also be included, although, so far as I am
aware, it has only been seen in dogs that have been subjected to feeding
experiments.

Another nematode common to the fox and dogs, and infesting the cæcum,
is the whipworm (_Trichocephalus depressiusculus_). It is very rare
in the dog. Lastly, there is the important little strongyloid worm
generally known as _Dochmius trigonocephalus_. At the hands of Leuckart
the general structure and development of this entozoon have received
complete elucidation. It infests the small intestines, and is found
alike in the fox, wolf, and cheetah. It has also been obtained from
_Canis lagopus_ and _C. azaræ_. Dr Krabbe did not encounter this worm in
Icelandic dogs; nevertheless, he obtained it in a blue fox which died
in Kjoerbolling’s menagerie, and which had come from Iceland. In Danish
dogs it occurred in less than 2 per cent. The embryos of this worm are
rhabditiform and possess three long bristle-like teeth, the slender
tail being furnished with a distinct appendage at the tip. They develop
in moist situations, where they feed freely, grow rapidly, and change
their skins, throwing off the caudal tip with the first month. It seems
evident that they do not require a change of hosts, since Leuckart
succeeded in rearing the sexually-mature _Dochmii_ by introducing
the rhabditiform larvæ into the stomach of the dog; moreover, his
experiments upon water-snails belonging to the genus _Physa_ gave
negative results.

Of Arachnidan parasites (_Trachearia_) infesting the dog, by far the
most interesting is the well-known _Pentastoma tænioides_, shown by
Leuckart to be the adult condition of the still better known _Pentastoma
denticulatum_. It resides in the nasal sinuses. As already mentioned in
a former part of this work, these parasites present four marked stages
of growth, namely (1), the embryo, (2) the pupa, (3) the active larva
(_P. denticulatum_), and (4) the sexually-mature worm. As the eggs and
their embryonic contents are lodged in the nasal mucus of the dog, and
are commonly distributed by the act of sneezing on the part of the
animal, the sources of infection are not far to seek. Clearly the larvæ
usually get introduced to the bodies of mankind and herbivorous animals
by the ingestion of unclean vegetable matter. The embryos set free in
the stomach bore their way to the liver and other viscera, in which
organs encystation and moulting subsequently take place. The fondling
of dogs infested by pentastomes may prove dangerous by a more direct
transference of the eggs to the hands and mouth. As regards the dog, the
adult parasite has been known to prove fatal. A very striking instance
of this kind was recorded by Prof. Dick, where the worms wandered into
the trachea producing asphyxia.

The ectozoa of the dog, though not numerous as species, are of
importance in relation to mange. The follicle-mites form a family by
themselves (_Demodicidæ_), and, as already observed, those infesting the
dog and cat are, alike, mere varieties of the human species (_Demodex
folliculorum_, var. _caninus_ and var. _cati_). Whilst the human
parasite restricts itself to the face, the canine variety (fig. 52)
will occupy any part of the dog’s body. The follicle-mite of the cat,
however, usually confines itself to the ear. According to Mégnin, to
whose beautiful monograph we owe so much, two or three dozen of these
parasites may be found occupying a single follicle of the dog. Acne-like
pustules are thus formed, and when they are very numerous death may
result from the excessive irritation, which is usually accompanied
with depilation. An interesting example of this kind recently occurred
at the Royal Veterinary College. In regard to the ordinary mange-mite
(_Sarcoptes canis_, Gerlach) M. Mégnin points out that it is in all
respects identical with the human itch-insect. In the wolf and fox,
however, the same species forms well-marked varieties (_S. scabiei_,
var. _lupi_ and var. _vulpis_). As regards true insect parasites and
tormentors of the dog, I can only allude to a few of them. In tropical
America dogs are said to be attacked by the larvæ of a species of gadfly
(_Œstrus canis_), whilst in Africa they are often fatally bitten by the
tsetse (_Glossina morsitans_). In addition to the flies (_Diptera_),
several kinds of fleas (_Aphaniptera_) frequently prove troublesome
(_Pulex canis_, _P. martis_, and _P. penetrans_), and the same may
be said of certain lice (_Hemiptera_). The common louse of the dog
(_Trichodectes latus_) proves especially noxious to young puppies. Of
the two other species, namely, _Hæmatopinus piliferus_ and _H. canis_,
the former is tolerably common, whilst the latter is comparatively
rare. This species is also found on the ferret. A new form of mite
(_Chorioptes ecaudatus_), infesting the ears of the ferret, has recently
been described by M. Mégnin.

I have already referred to several of the parasites of the cat-tribe
(_Felidæ_), but some others require notice. Only two flukes (_Amphistoma
truncatum_ and _Hemistoma cordatum_) have been described as infesting
the cat. Of the tapeworms, _Tænia crassicollis_ is the best known. This
is derived from _Cysticercus fasciolaris_ of the mouse and rat. It is
not uncommon to find this scolex in the sexually-immature tænioid state
in the liver, measuring six or seven inches in length. An exceedingly
interesting communication by Dr Romano, of Gemona (Frioul), demonstrates
the possibility of severe feline epizoöty as due to this entozoon. As
I gather from an account given in the journal quoted below, “during
the summer of 1876, Dr Romano was informed by his confrère Dr Leoncini,
a physician practising at Osoppo, that for about a fortnight most of
the cats in a certain hamlet of the town had died without appreciable
cause after presenting the following symptoms:--Gradual wasting, with
complete loss of appetite, retracted abdomen, slight diarrhœa at first,
then constipation, abundant saliva, contraction of the elevating muscles
of the upper lip in some subjects, great prostration of strength, loss
of the visual faculty. Some of the feline patients no longer heard or
appeared no longer to hear their master’s voice; some vomited and seemed
to experience relief, for the appetite improved, but they soon died
like the others. Nervous phenomena, epileptiform convulsions, and more
frequently colic, also showed themselves. Having visited the locality
(of the outbreak), Dr Romano could not at first procure any corpses for
the post-mortem examination, for the children had thrown them into the
Tagliamento, which flows at the foot of the fortress of Osoppo. It was
only after the lapse of some days that he was able to open one of the
animals which had just succumbed. The principal evils were remarked in
the stomach, the walls of which were retracted and formed the seat of a
catarrhal inflammation, from the products of which a long, white, flat
worm was removed with care for examination. All the other organs were
in good condition. The examination of the helminth in the stomach, made
with the help of Dr Leoncini and Fachini, showed that the flat worm
(white, and with the body divided into rings, 12 centimètres long, and 5
or 6 millimètres broad) had all the characters of the tænias, and this
was confirmed by a microscopic examination of the head. A few days later
Dr Romano made an autopsy of two other cats. In one of the corpses he
noted the alterations described above, and found a tænia smaller than
the first; in the other the same lesions without any helminth. This
negative circumstance very naturally disconcerted Dr Romano, but several
people of the place came to assure him that they had seen their cats,
during the course of the malady, after violent and repeated efforts
at vomiting, throw up a sort of white cord, which they recognised
as corresponding with the tænia he showed them. Thus confirmed and
reassured in his diagnosis, Dr Romano sought to identify the species.”
In this connection it is specially interesting to note that “during the
whole summer the inhabitants of Osoppo had been over-run by bands of
rats proceeding from the fortress. They were combated by means of cats,
and it was the best hunters among the felines that succumbed. Here was,
therefore, a striking relation of cause and effect which could not be
gainsayed.” Dr Romano communicated his observations to the National and
Royal Veterinary Society, but by an error in the report the species
appears to have been described as _Tænia tenuicollis_ instead of _T.
crassicollis_. In this connection I have only further to add that the
wild cat is infested by a tapeworm scarcely an inch in length (_Tænia
lineata_). A species of Bothriocephalus (_B. decipiens_) likewise
infests the domestic cat, in common with most of the wild felines, such
as the tiger, puma, ounce, and jaguar. Dr Bancroft brought me a specimen
from an Australian cat. The nematodes of the cats are very abundant.
Dr Bellingham found a trichosome (_T. felis cati_) in the urinary
bladder of the wild cat. This is probably identical with _T. plica_. A
tolerably common nematode is _Dochmius tubæformis_, which occurs not
only in the cat but also in the leopard, puma, jaguar, ounce, panther,
and also in _Felis tigrina_ and _F. mellivora_. In the last-named and
in other Brazilian felines an echinorhynchus (_E. campanulatus_) was
found by Natterer. A strongyle (_Sclerostoma dispar_) infests the lungs
of the puma. A species of spiroptera (_S. subæqualis_, Molin) infests
the œsophagus and stomach of the lion and tiger. Redi also noticed
a species of Filaria beneath the skin of the lion. _Physaloptera
terdentata_ (Molin) and _P. digitata_ (Schneider) infest the stomach
of the puma. I can only allude also to _Tænia laticollis_ of the lynx,
_Pentastoma recurvatum_, occupying the frontal sinuses and air-passages
of the ounce, and _Ligula reptans_ the subcutaneous tissues of the
leopard. Lastly, there is the _Olulanus tricuspis_ of the domestic
cat. I have examined the lungs of three cats containing this parasite,
which was first described as an entirely new species by Leuckart. The
adult worms, only 1/25″ in length, occupy the walls of the stomach.
Thence they are apt to migrate or stray into the lungs and liver,
where they encyst themselves. When myriads of them are thus encysted a
kind of nematode tuberculosis is set up. This disease I have elsewhere
called _olulaniasis_. Ordinarily, however, the encysted condition of
_olulanus_ is to be found in the muscles of mice, which are thus said to
be olulanised. Clearly, as Leuckart’s experiments substantially prove,
the domestic cat acquires the adult worm by catching and devouring
olulanised rodents. Every now and then the disorder thus created
produces a virulent and fatal feline epizoöty.

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the Dog (asserting that neither strong whisky nor boiling water would
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new generic type of Entozoon (Acanthocheilonema) from the Aard Wolf
(Proteles),” ‘Proc. Zool. Soc. of Lond.,’ Jan. 13, 1870.--_Idem_, “On
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1872.--_Idem_, “Remarks on the Life-epochs (biotomes) of _T. cœnurus_
and _T. echinococcus_,” in a paper on ‘Animal Individuality,’ ‘Journ.
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Heart (Mr. M’Innes’ specimen from Charleston),” the ‘Veterinarian,’
Feb., 1875.--_Idem_, “Note of Lewis’ Discoveries,” in ‘Nature,’ March
11, 1875, vol. ii, p. 363.--_Idem_, “Remarks on _Eustrongylus gigas_”
in the ‘Veterinarian,’ April, 1879.--_Coles, E. C._, “Worms in the
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J. J._, “Death of Dogs from Worms in the Heart,” the ‘Field,’ Feb.
24, 1872.--_Davaine_, ‘Traité,’ l. c., 2nd edit., p. 290 (for refs.
to lit. of _Strongylus gigas_).--_Delafond_ (with _Grube_), “Note on
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genus Filaria,” from ‘Ann. de Chimie et de Physique,’ in ‘Ann. of Nat.
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1859.--_Idem_, ‘Una monog. del gen. Physaloptera (_P. tordentata_),’
1860, s. 17.--_Idem_, ‘Una monog. del gen. Spiroptera (_S.
subæqualis_),’ 1860, s. 13.--_Nettleship, E._, “Notes on the Rearing of
_Tænia echinococcus_ in the Dog from Hydatids, with some observations
on the anatomy of the adult worm,” ‘Proc. Roy. Soc.,’ 1866, No. 86,
p. 224, with figs.--_Noseda, B._, “Six Strongyles in the Kidney of
the Agouara-gouazura or Puma,” in Don F. de Azara’s ‘Quadrupèdes du
Paraguay,’ Paris, 1801 (see also Azara, Bibl. No. 28).--_Osborne, T.
C._, “Worms found in the Heart and Blood-vessels of a Dog (with symptoms
of hydrophobia),” ‘Western Med. Journ.,’ rep. in ‘Bost. Med. and
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Bronchitis in Dogs (from Strongyles),” ‘Veterinarian,’ June, 1877,
p. 387.--_Owen_, “On the Anatomy of _Linguatala tænioides_,” ‘Trans.
Zool. Soc.,’ vol. i, 1835, and in ‘Lond. Med. Gaz.,’ 1835.--_Idem_,
“Anatomical description of two species of Entozoa, from the Stomach of
a Tiger, one of which forms a new genus, Gnathostoma,” ‘Proc. Zool.
Soc.,’ part iv, 1836.--_Parona_ (and _Grassi_), “On a new Species
of Dochmius (_D. balsami_),” ‘Reale Instituto Lombardo di Scienze
e Lettere, Rendiconti,’ vol. x, fasc. vi, 1877.--_Raynold, T. M._,
“Tapeworm in the Pointer and Spaniel,” ‘Veterinarian,’ vol. xiv, p. 694,
1841.--_Romano_, “Epizoöty amongst Cats from _Tænia crassicollis_,”
‘Giornale di med. vet. practica,’ Août, 1877, and in ‘Journ. de Méd.
Vét.,’ Avril, 1878.--_Schuppert, M._, “Mechanical Obstruction of the
Heart (of a Dog) by Entozoa, causing Death,” ‘New Orleans Med. News
and Hosp. Gaz.,’ Jan., 1858, also ‘Bost. Med. and Surg. Journ.,’ vol.
lvii, 1857-58, and in ‘Med.-Chir. Rev.,’ 1858.--_Stirling_, “On the
Changes produced in the Lungs by the Embryos of _Olulanus tricuspis_,”
‘Quart. Journ. Micr. Sci.,’ 1877, p. 145.--_Van Beneden_, “On the
Transmigration of the Entozoa” (in answer to MM. Pouchet and Verrier),
from the French, by Busk, in ‘Quart. Journ. Micr. Sci.,’ 1862.--_Idem_,
“Researches on the Intestinal Worms,” from Van der Hoeven’s abstr. in
the ‘Nederlandsch Tijdschrift voor Geneeskunde,’ in ‘Ann. Nat. Hist.,’
vol. iii, 3rd ser., 1859.--_Idem_, “New Obs. on the Development of the
Intestinal Worms,” from ‘Compt. Rend.,’ in ‘Ann. Nat. Hist.,’ vol.
xiii, 2nd ser., 1854.--_Idem_, “On _Filaroides mustelarum_,” ‘Mém. sur
les vers intest.,’ 1858, p. 267.--_Welch_, “On _Filaria immitis_,”
‘Lancet,’ March 8, 1873; also in ‘Month. Micr. Journ.,’ Oct., 1873, p.
157 (with three plates).--_Wilson, W._, “A Parasitic Worm infesting the
Air Sinuses of the Weasel,” ‘Midland Naturalist,’ May, 1878.--_Wright_,
“On Worms found in the Pulmonary Artery of a Dog,” ‘Lancet,’ 1845, and
in ‘Veterinarian,’ vol. xviii, p. 52, 1845.--_Youatt_, “On Tumours
(containing Entozoa) in the Stomach of a young Tiger,” ‘Veterinarian,’
vol. x, p. 619, 1837; see also Owen on ‘Gnathostoma.’--_Idem_, “Worms
(_Ascaris marginata_) in the Nose of a Dog,” ‘Veterinarian,’ vol. v, p.
337, 1832.


PART V (PINNIPEDIA).

Following the order of classification adopted in my description of the
Mammalia in the ‘Museum of Natural History,’ I proceed to speak of the
internal parasites of the seals (_Phocidæ_) and walruses (_Trichecidæ_).
From their piscivorous habits one would naturally expect the seals to be
largely infested with entozoa, and yet, though sufficiently victimised,
they are not liable to entertain so great a variety of helminths as the
fishes themselves on which they feed.

The flukes observed in _Phoca vitulina_ are _Distoma acanthoides_ and
_Amphistoma truncatum_, the latter occurring also in _P. grœnlandica_.
In another seal (_P. barbata_) we have _D. tenuicolle_. The nematodes
are more numerous. The best-known is the maw-worm (_Ascaris osculata_),
which seems to be always present in full-grown seals of every kind. In
the years 1862-64 I conducted a series of experiments with the eggs
of this worm. I reared embryos both in salt and fresh water, but the
administration of the young worms to various animals led to no result.
However, I succeeded in watching the growth of the embryos until they
had acquired well-marked digestive organs and a length of 1/25″, their
size when emerging from the egg-shell in the water having been about
1/150″ only. The large strongyle (_Eustrongylus gigas_) has been found
in various organs of the common seal. Of more interest are the _Filariæ_
found in the heart of seals, which in many respects resemble those
obtained from the same situation in dogs. Professors Joly, Leidy, and
myself, have each described a species, but apparently our descriptions
all refer to one and the same parasite. It has also been seen by Camill
Heller. The close correspondency in size and other characters of
Leidy’s _Filaria spirocauda_ and my _Filaria hebetata_ leaves little
doubt as to their identity. As the worms were both originally noticed
by Leidy and Joly in 1858, I cannot pronounce upon the question of
priority of discovery. By Joly the worm was called _F. cordis phocæ_.
In Leidy’s and in my own specimens the males were four inches long, and
the females six inches; they extended up to 8″ in some of the American
examples. The worms found by Prof. Joly were all females. Professor
Millen Coughtrey, who furnished me with the seal’s heart, stated that
it was obtained from a male hoodcap (_Stemmatopus cristatus_), a rare
visitant of our British coasts. This seal was captured on the Cheshire
side of the Mersey river. Leidy and Joly obtained their specimens from
_Phoca vitulina_. In the common seal have also been found _Ligula
crispa_, _Schistocephalus dimorphus_, and _Echinorhynchus strumosus_.
In other seals a not uncommon tapeworm of the Bothriocephalous type
is that called _Dibothrium hians_ by Diesing. To Prof. Krabbe I am
indebted for a specimen of _Bothriocephalus fasciatus_ taken from _Phoca
hispida_. There is a nematode of frequent occurrence in _P. hispida_
and _P. grœnlandica_. This is the _Ophiostoma dispar_ of Rudolphi. In
addition to the above I can only add that _P. barbata_ is infested by
_Liorhynchus gracilescens_, occupying the stomach, and by a tapeworm,
_Tetrabothrium anthocephalum_, which is found in the lower part of the
large intestine.

[Illustration: FIG. 59.--_Ascaris osculata._ _a_, Male; _b_, female.
Natural size. Original.]

BIBLIOGRAPHY (No. 46).--_Cobbold_, “Description of _F. hebetata_,” in
‘Notes on Entozoa,’ part i, sp. 3, ‘Proc. Zool. Soc.,’ Nov. 18th, 1873,
p. 741.--_Idem_, “On _Ascaris osculata_,” in ‘Report of Experiments
respecting the development and migrations of the Entozoa;’ ‘Brit. Assoc.
Trans.,’ 1864, p. 114.--_Heller, C._, in ‘Schrift der zool.-botan.
Gesellsch.,’ Wien, 1858, s. 83.--_Joly_, “On a new Species of Hæmatozoon
of the genus _Filaria_, observed in the heart of a seal;” from ‘Compt.
Rend. Acad. Sci.,’ 1856, p. 403, in ‘Ann. Nat. Hist.,’ vol. i, 3rd
ser., 1858; also abstr. in the ‘Year Book,’ 1859.--_Leidy, J._, (_E.
spirocauda_) in ‘Proc. Philad. Acad.,’ 1858, p. 112.


PART VI (RODENTIA).

Though very numerous, the parasites of this order are chiefly
interesting as embracing those of the hares and rabbits, moles, mice,
rats, squirrels, and beavers. Some slight notice, however, will be given
of the entozoa of each of the eleven families into which the order may
be divided.

The squirrels (_Sciuridæ_) are liable to be infested by the common liver
fluke (_F. hepatica_), and also, it is said, by a cysticercus (_C.
tenuicollis_). I have never encountered this bladder worm, but in 1864 I
described some polycephalous hydatids (_Cœnuri_) which I obtained from
the viscera of an American squirrel. I think the host was of the same
species (_Sciurus vulpinus_) as that from which Mr Chapman has since
obtained an example of Echinorhynchus (_E. moniliformis_). This worm
also infests the hamster. A very small female round worm, probably a
strongyle, was described by Rudolphi as _Ascaris acutissima_. It infests
the cæcum of the common squirrel, in which host a species of tapeworm
is tolerably frequent (_Tænia dendritica_). The common European marmot
is infested by _T. pectinata_, so abundant in hares and rabbits. I
have also noticed it as occurring in the Canadian porcupine (_Hystrix
dorsata_). The dormice (_Myoxidæ_) are not much troubled with parasites,
at least I have not encountered any in our common _Myoxus avellanarius_.
In _M. glis_, however, a tapeworm, and at least one species of strongyle
(_S. gracilis_), have been observed. Dujardin described very fully
another strongyle (_S. lævis_) from _M. nitela_, from the long-tailed
field-mouse (_Mus sylvatica_), and from _Arvicola subterraneus_. The
other species are _Trichosoma myoxi nitelæ_, and _Ophiostoma cristatum_
from _Myoxus dryas_, and _M. muscardinus_. The jerboas (_Dipodidæ_),
in common with the hamster and several species of true mice, are apt to
be infested by _Ascaris tetraptera_; and a small nematoid, apparently
immature, was noticed by Otto in the intestines and in the abdominal
walls and cavity of _Dipus tetradactylus_. Mice, properly so called, are
largely infested, as is also the hamster (_Cricetus vulgaris_), which I
include in the _Muridæ_. In addition to the parasites already mentioned,
the hamster is infested by _Tænia straminea_. Along with examples of
this tapeworm I have received from Dr Murie some acephalocysts found in
a hamster which died at the Zoological Gardens.

Flukes exist in the long-tailed field-mouse (_Distoma vitta_ and _D.
recurvum_), but I have not seen any in our common mice and rats.
However, Dujardin describes a distome (_D. spiculator_) in the brown
rat (_Mus decumanus_). One of the tapeworms observed in the mouse (_M.
musculus_) is _Tænia pusilla_, also found in the rat (_M. rattus_)
and long-tailed field-mouse. The house-mouse likewise harbors _T.
microstoma_ and _T. leptocephala_; and an immature cestode has also been
seen in the abdomen, probably a species of _Ligula_. Various species of
rat also harbor _T. diminuta_. In regard to the round worms one of the
most common species is _Ascaris oxyura_. This not only occurs in rats
and mice, but also in voles, water-rats, and many other rodents. The
rodents’ whipworm (_Trichocephalus nodosus_) is yet more common in the
lemmings, rats, voles, and mice; another species (_T. unguiculatus_),
taking its place in hares and rabbits, and yet another (_T. affinis_)
in the porcupine. Another nematoid, very common in mice, is _Spiroptera
obtusa_, occupying the stomach. I have seen a mouse with its abdomen so
distended by their presence that the animal could scarcely run along the
pathway where it was killed by being trod upon. According to Marchi,
the young of this entozoon dwell in the fat surrounding the alimentary
canal of the larva of an insect (_Tenebrio molitor_). When noticing the
parasites of the cat I referred to Leuckart’s interesting discovery
of the relations subsisting between the adult _Olulanus tricuspis_,
found in the stomach walls of that feline, and the immature encysted
worms, found not only as wanderers in the cat itself but also in the
muscles of mice. The olulanised mouse is thus an intermediate host.
Rats and mice also play the part of intermediary bearers in the case of
two other species of entozoa, namely, _Trichina spiralis_ and _Tænia
crassicollis_, the tænioid scolex or larval condition of the cat’s
tapeworm being familiarly known as _Cysticercus fasciolaris_. This
sexually-immature tapeworm infests many other rodents, especially the
voles (_Arvicolidæ_). In regard to _Trichinæ_ it must not be forgotten
that their presence in rats is not uncommon in some parts of Europe;
and this circumstance may explain the recurrence of trichinosis (first
in hogs and then in man) in certain outlying districts. Only in this
way can the Cumberland outbreak in this country be accounted for. Here
I cannot dwell upon the subject, but in this connection I may observe
that Bakody has in a very convincing manner described a new variety or
species of Trichina, found by him infesting the walls of the stomach
and intestine of rats. In the first instance he detected the worm in
association with the ordinary _T. spiralis_, but afterwards separately.
He also obtained it in fowls. The species should be called _Trichina
Bakodyii_. Possibly the nematodes observed by Colin in 1863 also refer
to this worm. They occupied tubercles in the liver of a rat. In regard
to the beavers (_Castoridæ_) it appears that they harbor many species
of round worms, and also several flukes, but they do not appear to have
been very much studied. In Morgan’s work on the American beaver there is
a notice in which it is stated that Dr Ely found a very fine filamentous
worm 40‴ in length. This does not seem to correspond with _Ascaris
castoris_ (Rud.). He also speaks of large numbers of a slender white
worm, 3″ to 5″ in length, found in the peritoneal cavity, and referable
to the genus _Filaria_. This cannot be confounded with _Trichocephalus
castori_ (Rud.). Moreover, he describes a strongyle (_Sclerostoma_)
as infesting the colon, and especially the cæcum. These all appear
to be new to science. The _Fasciola hepatica_ is occasionally found
in the liver, but the most common helminth of beavers is _Amphistoma
subtriquetrum_. Specimens of this worm may be seen in the British and
Hunterian Museums. As regards the porcupines (_Hystricidæ_) I have
already mentioned the occurrence of a tapeworm in the common species.
The larval _Pentastoma denticulatum_ has been found by Otto attached to
the surface of the lungs, and Redi, about two centuries back, noticed
small nematodes lodged in tubercles of the œsophagus. The late C. M.
Diesing obtained _Trichocephalus affinis_ from the intestines. So far as
I am aware, little or nothing has been said respecting the helminths of
the _Octodontidæ_, _Chinchillidæ_, and _Cavidæ_. Like other European
investigators I have dissected guinea pigs (_Cavia aperœa_) without
finding any parasites; but in Brazil a small species of ascaris (_A.
uncinata_) was found by Natterer in this animal and also in the paca
(_Cœlogenys paca_). The agoutis (_Dasyprocta_) harbor _Trichocephalus
gracilis_.

The entozoa of the duplicidentate rodents (_Leporidæ_) acquire
importance from the fact of their abundance and from the intimate
relation which some of them bear to parasites infesting the dog and
other animals. Thus, the two commonest kinds of fluke infesting
cattle (_Fasc. hepatica_ and _Dist. lanceolatum_) also attack hares
and rabbits; the former parasite often producing the rot disease,
which is almost as fatal to the rodents as it is to the ruminants.
Mutual infection occasionally results from this circumstance by the
distribution of germs. All experiment-conducting helminthologists have
reared _Tænia serrata_ from the _Cysticercus pisiformis_; nevertheless,
several English Manuals of Zoology persist in propagating the old
error of Von Siebold, who supposed he had reared this tapeworm by the
administration of Cœnuri. So far as I am aware, no feeding experiments
have been conducted with the Cœnuri of rabbits (_C. cuniculi_). These
bladderworms infest the soft parts of the body, often producing tumours
having a very unsightly appearance. For details I must refer to the
papers quoted below. The Norfolk warreners call the infested hosts
“bladdery rabbits.” Though apparently most abundant in the eastern
counties of England, these diseased rabbits are by no means confined
to that quarter. Through Mr Alston’s help I have received specimens
of _Cœnurus cuniculi_ from Ayrshire, Scotland. Probably this form of
Cœnurus occurs wherever rabbits live. In Italy a case is recorded
by Perroncito from the abdominal cavity of a rabbit (_coniglio_).
Every experimenter is more or less familiar with the cestode larvæ
(_C. pisiformis_) found wandering in the abdominal cavity. These
were regarded as flukes by Kuhn (_Monostoma leporis_). I need hardly
remark that the developmental and structural changes undergone by
these Cysticerci during their residence within the rabbit have been
exhaustively followed out and treated of by Leuckart. Without dwelling
on this subject, I must in justice add that in this relation the
special labors of Küchenmeister, Van Beneden, Haubner, Wagener, Röll,
Eschricht, and Möller played no inconspicuous part. My own efforts
in 1857, and subsequently, were not unattended with success. It
therefore seems to me, without prejudice to the recent experiences of
De Sylvestre and others, that further experiments in this immediate
connection are unnecessary. As regards the nematodes of leporine
rodents, probably the most important is _Strongylus commutatus_. This
parasite, like its husk-producing congeners, infesting calves and
lambs, occasionally sweeps off great numbers of hares. Such an epizoöty
occurred in Thuringia in 1864. The most frequent intestinal parasite
of rodents is probably _Oxyuris ambigua_, but _Strong. retortæformis_
is tolerably abundant in the hare, and _Trichocephalus unguiculatus_
is liable to occur in all leporines. I know nothing of the so-called
_Strong. strigosus_ of rabbits, but Bellingham found it in Ireland.
Olfers and Natterer obtained a small ascaris (_A. veligera_) from
_Lepus braziliensis_; but I cannot help thinking that the large measle
(_Cysticercus macrocystis_) described by Diesing as three inches in
length, and obtained from the same rodent, must either have been
_Cœnurus cuniculi_ or else another form of polycephalous hydatid.

In reference to the ectozoa of rodents it may be said that they are very
numerous. Acari infest rats and mice, and especially leporines. Thus,
in the mouse are found _Sarcoptes notoedre_, Bourguignon, var. _muris_,
Mégnin, _Sarc. musculinus_, Koch, and _Myobia musculi_, Claparède. It
is not very generally known that wild rabbits are apt to be attacked
by the common autumnal spider (_Leptus autumnalis_), whence, as once
happened with myself, they may be transferred to the human body. The
ears of tame rabbits are sometimes covered with acari, which are easily
destroyed by the cautious application of a mixture of carbolic acid and
olive oil (one of acid to six of the oil). Rodents also harbor fleas.
At a meeting of the Entomological Society in 1875 Mr Vernall showed
living specimens from the ears of a rabbit, and Messrs Cole and W. A.
Lewis stated that they had obtained fleas from the hedgehog and European
marmot respectively.

BIBLIOGRAPHY (No. 47).--_Beneden_ (see Van Beneden below).--_Capelle,
J._, Extr. from a letter, in which the author states that he had
“found worms of the tænia kind in the liver of sixteen out of eighteen
rats,” ‘Med. Commentaries,’ vol. xix, p. 139, 1794; see also ‘Trans.
Coll. Phys. of Philad.,’ vol. i, part ii, p. 60, 1793.--_Chapman, H.
C._, “Echinorhynchus in Squirrel,” ‘Proc. Acad. Philad.,’ 1874, p.
76.--_Cobbold_, “Note on Cœnurus (from a squirrel),” ‘Proc. Linn.
Soc.,’ May 5, 1864.--_Idem_, “On the occurrence of _Tænia pectinata_
in the Porcupine (_Hystrix dorsata_),” in a letter to Dr. Lawson in the
‘Canadian Naturalist and Geologist,’ 1862.--_Idem_, ‘On _T. serrata_,’
&c. (see Bibl. No. 45).--_Colin_, “On the presence of a Nematode Worm in
certain Tubercles of the Liver of a Rat,” from ‘Rec. de Méd. Vét.,’ in
‘Edin. Vet. Rev.,’ Oct., 1863.--_Leuckart_, ‘Die Blasenbandwürmer (u. s.
w.),’ 1858 (contains numerous details and figs. in ref. to _Cysticercus
pisiformis_ and _T. serrata_, &c.).--_Marchi, P._, ‘Mem. della R. Accad.
d. Sci. di Torino,’ xxv.--_Peacock_, “Remarks on the Liver of a Mouse
with Cysts containing Cysticerci,” ‘Lancet’ and ‘Trans. Path. Soc.,’
1855.--_Perroncito, E._, “Sopra un caso di Cœnurus (in the abdominal
cavity of a rabbit),” ‘Giornale Med. Veter.,’ 1876.--_Siebold_ (see Von
Siebold, below).--_Sylvestri, De_, “Experiments with _C. pisiformis_,”
‘Il. Med. Veterinario,’ 1871.--_Van Beneden_ (see Bibl. No.
45).--_Idem_, “On _Sciurus glacialis_ and its Parasites,” from ‘Bull. de
l’Acad. de Belgique,’ in ‘Ann. Nat. Hist.,’ vol. xiii, 1854.--_Verrall_,
in ‘Proc. Ent. Soc. Lond.,’ Feb. 15, 1875, p. 3.--_Von Siebold_, ‘Ueber
die Band-und Blasenwürmer,’ Leipsig, 1854, and Huxley’s edit. for Syd.
Soc., 1857.--_Idem_, “Experiments on the Transformation of the Cystoid
Worms into Tænias,” from ‘Ann. des Sci. Nat.,’ in ‘Ann. Nat. Hist.,’
vol. x, 1852.--_Idem_, “Helminthology,” trans. by Busk and pub. in ‘Ray
Soc. Rep. on Zool.,’ 1843-44, p. 446, London, 1847.--_Idem_, “On the
Transformation of _Cysticercus pisiformis_ into _Tænia serrata_,” from
‘Zeitsch. f. w. Zool.,’ in ‘Quart. Journ. Micr. Sci.,’ 1854.


PART VII (EDENTATA).

The entozoa of the edentulate mammals are not very numerous. So far as I
am aware only one species has been described from the scaly ant-eaters
(_Manidæ_). This is the small and probably immature ascaris noticed by
Whitefield in the walls of the stomach of the badgareit or short-tailed
pangolin (_Manis pentadactyla_). Amongst the true ant-eaters
(_Myrmecophagidæ_) a single round worm has also been observed, but
not adequately described. I allude to Marcgrav’s “find” in the little
ant-eater (_Myrmecophaga didactyla_). I observe that Rudolphi distinctly
refers to this edentate as the tamandua. Diesing does the same. The
ant-eaters are much infested by a thorn-headed worm (_Echinorhynchus
echinodiscus_). On the 1st November, 1875, I received from Prof. Flower
a jar labelled as follows: “Entozoon found attached to intestine of
tamandua ant-eater.” The parasite was procured from the society’s
gardens on August 12th, 1871. Natterer originally obtained this worm
from _Myrmecophaga jubata_ and _M. bivittata_. Croplin described it from
a _M. didactyla_ from Surinam (‘Wiegmann’s Archiv,’ 1849). I presume
that _M. tamandua_ answers to the _M. bivittata_ of Geoffroy, as well
as to the tridactyle and tetradactyle species of Linnæus. The parasite
in question was a female, measuring exactly 10 inches long, and had its
proboscis firmly anchored within the gut. The armadillos (_Dasypidæ_)
entertain a variety of nematodes. In 1858 I obtained several examples of
_Ascaris retusa_ from the rectum of a poyou or weasel-headed armadillo
(_Dasypus sexcinctus_). The worm was first procured by Natterer from
the black armadillo (_D. peba_), which host also harbors _Pentastoma
subcylindricum_. According to the “finds” of Natterer and the subsequent
descriptions by Diesing, the two most common helminths of the Brazilian
armadillos are _Aspidocephalus scoleciformis_ and _Trichocephalus
subspiralis_. As regards the sloths (_Bradypidæ_) it would seem that
they are particularly liable to entertain round worms. The Ai (_Bradypus
tridactylus_) is infested by _Strongylus leptocephalus_, _Spiroptera
gracilis_, _Sp. anterohelicina_, and _Sp. brachystoma_; whilst the unau
(_Cholœpus didactylus_) harbors the last-named species and also _Sp.
spiralis_. All these worms have been described by Molin, and, with the
exception of the two first named, were new to science when he wrote his
well-known monograph on the genus. They were collected by Natterer. All
the species infest either the stomach or intestines, with the exception
of _Sp. spiralis_. This singular worm, like the closely allied _Sp.
helicina_, infesting the feet of birds, has the habit of coiling itself
amongst the tendons of the digits of the hind limbs more especially.

[Illustration: FIG. 60.--Tail of the male _Ascaris retusa_. Enlarged.
Original.]

BIBLIOGRAPHY (No. 48).--_Cobbold_, “On some new Forms of Entozoa,”
‘Linn. Trans.,’ vol. xxii, p. 365, 1859.--_Idem_, “List of Entozoa,”
&c., ‘Proc. Zool. Soc.,’ March 26, 1861.--_Idem_, “Notes on Entozoa,”
part iii, ‘Proc. Zool. Soc.,’ Feb. 1, 1876, p. 202.--_Marcgrav_, in
his ‘Historia rerum nat. Brasil.,’ 1648, p. 226, and in ‘Rudolphi’s
Synopsis,’ p. 186.--_Molin_, “Una Monografia del gen. Spiroptera,” ‘Aus
dem Sitzungsb. d. m.-nat. Cl. d. k. Akad. d. Wissensch.,’ Bd. xxxviii,
1859, s. 911, Wien, 1860.--_Whitefield_, in ‘Edin. New. Phil. Journ.,’
edited by Jamieson, 1829, p. 58.


PART VIII (RUMINANTIA).

In the matter of parasites this order of mammalian animals stands second
in importance. An entire volume of the dimensions of the present would
barely do justice to the subject. Although in the article “Ruminantia”
in ‘Todd’s Cyclopædia,’ and in my popular treatise on the mammalia, I
have described the oxen (_Bovidæ_) and sheep (_Ægosceridæ_) as separate
families, I shall here speak of their entozoa together; and, at the
same time, I shall introduce occasional reference to the helminths
of the antelopes and gnoos (_Antilopidæ_), also of the giraffes
(_Camelopardidæ_), the deer tribe (_Cervidæ_), the camels, and the
llamas (_Camelidæ_). The parasites of the last family, however, will
necessarily stand somewhat apart.

Almost all ruminants harbor the liver fluke (_Fasciola hepatica_).
This worm has been found in every variety of the common ox and zebu
(_Bos taurus_, var. _Indicus_), in the sheep, goat, and argali (_Ovis
aries_, _Capra hircus_, and _G. argali_), in the antelopes and gazelle
(_A. dorcas_), in red-deer, roe, and fallow (_Cercus elaphus_, _C.
capreolus_, and _C. dama_), and in the two-humped camel (_Camelus
bactrianus_). A closely-allied but much larger species of fluke (_F.
gigantea_) infests the giraffe (_Camelopardalis_). All these animals are
more or less liable to suffer from the “rot” which is produced by these
flukes. Into the history of the affection the space at my command does
not permit me to enter, but as regards the development of the common
fluke I believe the following conclusions to be tolerably well founded.
I had long entertained the opinion that our common _Planorbis_ plays
the rôle of intermediate bearer, and this view has at length received
confirmation.

1. The liver fluke, in its sexually-mature state (_Fasc. hepatica_),
gives rise to the disease commonly called _rot_; this affection being
also locally termed _coathe_ (Dorsetshire, Devon), _iles_ (Cornwall),
and _bane_ (Somersetshire). In France it is known as the _Cachexie
aqueuse_, and more popularly as _pourriture_. In Germany the epidemic
disease is called _egelseuche_, and in a more limited sense either _die
Fäule_ or _die Leberkrankheit_.

[Illustration: FIG. 61.--_Fasciola hepatica._ Enlarged. After Blanchard.]

2. The _rot_ is especially prevalent during the spring of the year, at
which time the fluke itself and innumerable multitudes of the free eggs
are constantly escaping from the alimentary canal of the bearer. The
germs are thus ordinarily transferred to open pasture-grounds along with
the fæces of the bearer.

3. As it has been shown by dissections that the liver of a single sheep
may harbor several hundred flukes, and as, also, a single adult fluke is
capable of throwing off several thousand eggs, it is certain that any
rot-affected flock is capable of distributing millions of fluke germs.

4. Such flukes as have escaped the host per anum do not exhibit active
powers of locomotion. Their slight contractile movements, however, serve
the purpose of concealing them in the grass, and probably aid in the
further expulsion of eggs, which pass from the oviduct in single file.

5. After the death of the escaped flukes the further dispersion of the
eggs is facilitated by the subsequent decomposition of the parent worm,
and also by its disintegration, partly occasioned by the attacks of
insects. It has been calculated that the uterus of a full-grown fluke
may contain upwards of forty thousand eggs.

6. By the agency of winds, rains, insects, the feet of cattle, dogs,
rabbits, and other animals, as well as by man himself, the freed ova are
dispersed and carried to considerable distances; and thus it is that a
considerable proportion of them ultimately find their way into ponds,
ditches, canals, pools of all kinds, lakes, and running streams.

7. At the time of their expulsion the eggs exhibit a finely segmented
condition of the yolk. The egg-contents continue to develop whilst
outside the parent’s body, the granular matrix finally becoming
transformed into a ciliated embryo, which when set free follows the
habit of infusorial animalcules in general by swimming rapidly in the
water. The escape of the embryo is effected at the anterior pole of the
egg-shell, which is furnished with a lid that opens in consequence of
the action of prolonged immersion, aided by the vigorous movements of
the contained embryo.

8. The ciliated, free-swimming embryo, at the time of its birth,
exhibits the figure of an inverted cone, its anterior extremity, which
is broad and somewhat flattened, supporting a central proboscis-like
papilla. A small pigment spot placed dorsally, and having the form of a
cross, is supposed to be a rudimentary organ of vision. After the lapse
of a few days the cilia fall off, the embryo then assuming the character
of creeping larvæ (planulæ).

9. Notwithstanding its abridged locomotive powers the non-ciliated larvæ
sooner or later gain access to the body of an intermediary bearer,
within or upon whose tissues it becomes transformed into a kind of sac
or _sporocyst_. In this condition the larva is capable of developing,
agamogenetically, other larvæ in its interior. The sporocysts are highly
organised, forming _rediæ_. According to Willemoes-Suhm, the redia of
_Fasciola hepatica_ lives on the body of _Planorbis marginata_. This
organised nurse, which is about a line in length, is the _Cercaria
cystophora_ of Wagener. The progeny of this redia consists of armed
Cercariæ, which after a time quit the nurse to pass an independent
existence in the water.

10. In the cases of some species of fluke there is reason to believe
that before the _Cercariæ_ gain access to their final or definitive host
they re-enter the bodies of the mollusks. This they accomplish by means
of a boring apparatus, and having previously cast off their tails they
encyst themselves beneath the surface of the skin. In this new situation
they develop into the so-called _pupa_, which is at length passively
transferred with the fodder, or drink, to the digestive organs of the
host. In the case of _Fasc. hepatica_, as probably obtains also with
many other flukes, I think there can be no doubt that the Cercariæ pass
directly into the bodies of ruminating animals. The circumstance that
flukes of this species have been found beneath the human skin shows how
considerable are the boring powers of the armed Cercariæ.

In regard to the possibilities of fluke development, that will be best
understood by glancing at the constitution of the zoological individual.
The sum total of the products of a single germ may be tabulated as
follows:--

          Zoological individual (_Fasciola hepatica_).

  _a._ Ovum in all stages,            } First “biotome.”
  _b._ Ciliated free-swimming embryo, }
  _c._ Nurse, germ-sac, sporocyst (_redia_), } Second “biotome.”
  _d._ Active, migrating, tailed larva (_cercaria_), }
  _e._ Encysted, resting larva (_pupa_),             } Third “biotome.”
  _f._ Sexually-mature fluke (_fasciola_).           }

This is a fair representation of the life-phases of the fluke.
The life-phases are rarely less numerous or complicated than here
indicated, but Pagenstecher’s researches tend to prove that under
certain climatal conditions the number of larval forms may vary
considerably. In other words, the fluke individual does not comprise
any definite number of “zoöids,” although the kinds of zoöids are
limited. I recognise three “biotomes.” The first includes only one
temporary, independent life-phase, this is the ciliated animalcule,
which I call a “protozoöid.” The second “biotome” may comprise only a
solitary simple sporocyst or germ-sac (deuterozoöid), but an almost
indefinite multiplication of new and independent germ-sacs, as well as
other more highly organised “nurse formations,” may also be developed
from the primary sporocyst (secondary and tertiary “deuterozoöid”). The
third “biotome” embraces a large but variable number of “tritozoöids”
(_cercariæ_), an equal number, whatever that may be, of “tetartozoöids”
(pupæ), and, therefore, also, a similar number of “pemptozoöids”
(flukes).

Practically, other curious results arise out of the foregoing
considerations. For example, a single sheep may harbor 1000 flukes. Each
fluke will develop 10,000 to 40,000 eggs. Each egg may give rise to 370
zoöids. It thus appears that, if all the conditions were favorable,
a single fluke might originate between three and four millions of
individualised life-forms, whilst the solitary sheep itself would,
under the same circumstances, be the means of causing the production of
at least 3,000,000,000 fluke zoöids! Happily, no such results as this
can possibly occur in nature, since interfering agencies reduce the
favorable conditions. However, the balance of parasitic forms from all
sources is usually sufficient to destroy thousands of sheep annually.
The virulence of rot-epizoöty is entirely due to the presence of
conditions favoring the development of fluke larvæ.

As regards the injurious action of this parasite on animals, it is well
known that in particular years, in England alone, hundreds, and even
thousands, of sheep have been destroyed in a single season. A writer in
the ‘Edinburgh Veterinary Review’ for 1861 states that in the season of
1830-31 the estimated deaths of sheep from _rot_ was between one and two
millions. This would, of course, represent a money loss of something
like four million pounds sterling. As affording additional striking
instances of the disastrous effects of rot, I may cite the statements of
Davaine. Thus:--“In the neighbourhood of Arles alone, during the year
1812, no less than 300,000 sheep perished, and at Nimes and Montpellier
90,000. In the inner departments, during the epidemic of the years
1853-54, many cattle-breeders lost a fourth, a third, and even three
fourths of their flocks.” In like manner our English authority, Prof.
Simonds, furnished a variety of painful cases. Thus, on the estate of
Mr Cramp, of the Isle of Thanet, the _rot epidemic_ of 1824 “swept away
£3000 worth of his sheep in less than three months, compelling him to
give up his farm.” Scores of cases are on record where our English
farmers have individually lost three, four, five, six, seven, and even
eight hundred sheep in a single season; and many agriculturists have
thus become completely ruined.

Remarkable periodic outbreaks of this disease are recorded by Simonds
as occurring in England in the successive years of 1809, ’16, ’24, ’30,
’53, and ’60; whilst, for France, Davaine mentions 1809, ’12, ’16, ’17,
’20, ’29, ’30, ’53, and ’54, as the most remarkable years. It would
be interesting to know how far these outbreaks tally with the similar
outbreaks which have occurred in Holland, Germany, and other European
districts. The disease was prevalent during four separate years in
France and England at one and the same time. This, indeed, is no more
than we would naturally expect, considering that the extent of the
development of the larval forms must, in a great measure, be dependent
upon atmospheric conditions. A warm and moist season would alike prove
beneficial to the development of the larvæ and their intermediate
molluscan hosts. Their numbers would also multiply enormously; for, as
already remarked, the degree of non-sexual production of trematode larvæ
within their sporocysts is materially affected by climatic changes. On
the other hand, a fine, dry, open season will tend to check the growth
and wanderings of the larvæ, and thus render the flocks comparatively
secure.

Considerations like these sufficiently explain many of the crude
theories which were early propagated concerning the causes of this
disease, and in particular, the very generally prevalent notion that
water, and water alone, was the true source of the disease. Intelligent
cattle-breeders and agriculturists have all along observed that the
_rot_ was particularly virulent after long-continued wet weather, and
more especially so when there had been a succession of wet seasons. They
have likewise noticed that flocks grazing in low pastures and marshy
districts were much more liable to invasion than sheep which pastured
on higher and drier grounds, but noteworthy exceptions occurred in the
case of flocks feeding in the salt-water marshes of our eastern shores.
The latter circumstance appears to have suggested the common practice
of mixing salt with the food of sheep and cattle, both as a preventive
and curative agent; and there can be little doubt that this remedy
has always been attended with more or less satisfactory results. The
intelligible explanation of the good effected by this mode of treatment
we shall find to be intimately associated with a correct understanding
of the genetic relations of the entozoon, for it is certain that
the larvæ of _Fasciola hepatica_ exist in the bodies of fresh-water
snails. As already hinted from Willemoes-Suhm’s observations, it is not
improbable that the larvæ are confined to gasteropod mollusks belonging
to the genus Planorbis.

The symptoms produced by _rot_ are very striking. When the disease has
far advanced it is easy to know a rotten sheep, not only by its very
look, but still more convincingly, as I have myself tested, by slightly
pressing the hand over the region of the loins. In this region the
diseased animal is particularly weak, and the pressure thus applied
instantly causes it to wince. At the same time the hand feels a peculiar
sensation very unlike that communicated by the spine of a sound animal.
In bad cases the back becomes hollow, and there is a corresponding
pendulous condition of the abdomen. The spinal columns ultimately stick
out prominently, forming the so-called “razor-back.” As Professor
Simonds has well observed, in an earlier stage of the disease, “an
examination of the eye will readily assist in determining the nature of
the malady. If the lids are everted it will be found that the vessels
of the conjunctiva are turgid with pale or yellowish colored blood, the
whole part presenting a peculiar moist or watery appearance. Later on,
the same vessels become blanched and scarcely recognisable.” The skin
also becomes harsh and dry, losing its natural tint, and the wool is at
length rendered brittle, either becoming very easily detached or falling
off spontaneously.

The first thing noticeable in dissecting a rotten sheep is the wasted
and watery condition of all the tissues. There is a total absence of
that firm, fresh, carneous look which so distinctively characterises
the flesh in a state of health. Not only is the rigidity and firm
consistency of the muscles altogether wanting, but these structures
have lost that deep reddish color which normally exists. When the
abdominal cavity is opened a more or less abundant, clear, limpid, or
yellowish fluid will make its escape, and the entire visceral contents
will, at the same time, display a remarkably blanched aspect. These
pathological changes are also shared by the important organ especially
affected, namely, the liver. This gland has lost its general plumpness,
smoothness, and rich, reddish-brown color, and has become irregularly
knotted and uneven both at the surface and the margins, its coloring
being either a dirty chocolate brown, more or less strongly pronounced
at different parts, or it has a peculiar yellowish tint, which in places
is very pale and conspicuous. To the feel it is hard and brawny, and
when incised by the scalpel, yields a tough and, in places, a very
gritty sensation. On opening the gall-ducts a dark, thick, grumous,
biliary secretion oozes slowly out, together with several distomes,
which, if not dead, slowly curve upon themselves, and roll up like a
slip of heated parchment. On further slitting open the biliary passages,
they are found distended irregularly at various points, and in certain
situations many flukes are massed together, having caused the ducts
to form large sacs, in which the parasites are snugly ensconced. The
walls of the ducts are also much thickened in places, and hardened by a
deposit of coarse calcareous grains on their inner surface. Mr Simonds
says, that the “coats of the _ductus hepaticus_, as also of the _ductus
communis choledicus_, are not unfrequently so thick as to be upwards of
ten times their normal substance, and, likewise, so hard as to approach
the nature of cartilage.” Respecting their numbers, the greatest
variation exists. The presence of a few flukes in the liver is totally
insufficient to cause death; consequently, when a sheep dies from rot,
or is killed at a time when the disease has seriously impoverished the
animal, then we are sure to find the organ occupied by many dozen,
many score, or even several hundred flukes. Thus from a single liver
Bidloo obtained 800, Leuwenhoeck about 900, and Dupuy upwards of 1000
specimens. Even the occurrence of large numbers only destroys the
animal by slow degrees, and, possibly, without producing much physical
suffering, excepting, perhaps, in the later stages. Associated with
the above-described appearances, one also not unfrequently finds a
few flukes in the intestinal canal, whilst a still more interesting
pathological feature is seen in the fact that the bile contained in the
liver ducts is loaded with flukes’ eggs. In some cases there cannot be
less than tens or even hundreds of thousands. Not a few may also be
found in the intestinal canal and in the excrement about to be voided.
Occasionally dead specimens become surrounded by inspissated bile, and
gritty particles deposited in the liver ducts, thus forming the nuclei
of gall-stones. Mr Simonds mentions a remarkable instance, “where the
concretion was as large as an ordinary hen’s egg, and when broken up was
found to contain about a dozen dead flukes. It was lying in a pouch-like
cavity of one of the biliary ducts.”

In respect of treatment we all know that “prevention is better than
cure.” Moisture being essential to the growth and development of the
fluke-larvæ, it is clear that sheep cannot be infected so long as they
remain on high and dry grounds, and even in low pastures they can
scarcely take the disease so long as they are folded, and fed on hay,
turnips, and fodder procured from drier situations. When once the malady
has become fairly developed, internal remedies are of little avail, at
least, in view of producing a thorough cure. Palliative treatment may
undoubtedly do good, especially in cases where the disease is not very
strongly pronounced. The most important thing is the transference of the
rot-affected animals to dry ground and good shelter, supplying them, at
the same time, with a liberal quantity of manger food, such as beans,
peas, and other leguminous seeds. The fodder, of whatever kind, should
be frequently changed, and many other hygienic measures adopted, all
tending to promote the appetite and general health of the animal. An
admixture of salines is a matter of essential importance, especially in
cases where the disease is not far advanced. The beneficial effect of
salt is one of those few points on which nearly all parties are agreed,
and its preservative influence in the case of sheep fed upon salt-water
marsh-land has been previously explained. In regard, however, to the
legion of remedies which have from time to time been proposed, all I
need here say is, that most of them when fairly tested have been found
to fail ignominiously. Every year we hear of the adoption, often with
enthusiasm, of new so-called specifics, or of ancient medicines whose
employment had long fallen into disuse. Thus, for example, in the April
number of the ‘Journal des Vétérinaires du Midi’ for 1860, we find
M. Raynaud strongly recommending soot, in doses of from one to three
spoonfuls, to be followed up by the administration of a grain of lupin
for tonic purposes. In like manner, we received from France wonderful
accounts of the medicinal virtues of a certain fœtid oleaginous
compound, the value of which was put to a fair test by our distinguished
veterinarian, Professor Simonds. Having with infinite care and trouble
undertaken a series of experiments with the remedy in question, Mr
Simonds writes in the ‘Scottish Farmer and Horticulturist’ to the effect
that, as a result of his inquiries, he fears “we must conclude that this
supposed cure of _rot_ in sheep has proved quite ineffective for good.”
The last new “cure” announced is by Mr Robert Fletcher (‘Journ. Nat.
Agric. Soc. of Victoria,’ Dec., 1878).

The examination of rotten sheep is not altogether free from danger.
Professor Simonds tells us that in August, 1854, “a person of
intemperate habits, following the occupation of a country butcher,
was employed in skinning and dressing a number of rotten sheep on
the premises of a farmer in the county of Norfolk. The sheep were
necessarily opened when _warm_, and while he was so engaged he
complained greatly of the sickening smell. The same evening he was
attacked with choleraic disease, and two days afterwards was a corpse.”
This case is highly instructive and, when taken in connection with the
well-known fact that animals affected with the disease putrefy very
rapidly, clearly points to the necessity of removing slaughter-houses
far away from densely populated localities.

Notwithstanding the above statement, there is little or no danger to be
apprehended from the consumption of the flesh of rot-affected animals.
On this vexed question we have the strong testimony of the late Dr
Rowe, of Australia, who, after leaving the medical profession, became a
large and successful stockowner, and devoted himself especially to this
question. Dr Rowe, writing from the Goulburn district, said:--“The mere
presence of flukes in the viscera of an animal is no proof that it is
unfit for human food. For inspectors of slaughter-houses to adopt such
a test of wholesome food would be the greatest mistake. It would afford
no protection to the public against unhealthy food, would increase the
price of animals, and be ruinous to our farmers and graziers. If the
consumption of flukey beef and mutton were prejudicial to the health of
man, there would be very few people alive in this part of the colony;
for, to my certain knowledge, they have had no other animal food to live
upon for the last twenty-five years, yet for physical ability I believe
they may be favorably compared with the inhabitants of any other part of
Australia.” Speaking of his own experiences, Dr Rowe avers that he found
the common liver fluke in sheep, cattle, goats, opossums, kangaroos,
geese, ducks, and other creatures, but he had never encountered it in
men, dogs, or pigs. On the whole I think we may agree with Dr Rowe, in
regarding the consumption of the flesh of rot-affected animals as free
from danger provided only the meat, be well or even moderately well
cooked. It must be borne in mind, however, that an essential objection
to its consumption lies in the fact that the watery and otherwise
chemically deteriorated flesh is comparatively innutritious. It must
also be noted that the meat-supply from fluke-affected animals, as
usually sold in the markets, is chiefly derived from animals which have
only entered the early stage of the disorder, that is, long before the
watery and wasted condition of the muscles has fairly set in.

Respecting the other trematodes I have to observe that _Distoma
lanceolatum_ not only infests the liver ducts of cattle and sheep,
but also the deer tribe. Its larvæ are likewise supposed to reside
in _Planorbis marginatus_. Still more common and widespread amongst
ruminants is the _Amphistoma conicum_, occupying the paunch. It has
been found in the ox, sheep, musk-ox, elk, roe, fallow, red-deer,
goat, and dorcas-antelope; also in _Cerrus campestris_, _C. nambi_, _C.
rufus_, and _C. simplicicornis_. Prof. Garrod has also recently shown
me examples from the sambu deer of India (_C. Aristotelis_). Diesing’s
_A. lunatum_, infesting _Cerrus dichotomus_, is inadmissible. Two other
species of Amphistome (_A. explanatum_, _A. crumeniferum_) are said to
infest the zebu; and I have described another (_A. tuberculatum_) from
the intestines of Indian cattle. An aberrant amphistomatoid entozoon
(_Gyrocotyle rugosa_) has been found in a Cape antelope (_A. pygarga_).
Of more interest, however, is the circumstance that Dr Sonsino has
discovered a species of Bilharzia (_B. bovis_) in Egyptian cattle and
in sheep. The eggs of this species are distinctive, being fusiform and
narrowed towards either pole.

Comparatively few tapeworms are found in ruminants. Cattle are infested
by _Tænia expansa_ and _T. denticulata_, the former of these two species
being also more or less prevalent in sheep, antelopes, and deer. Other
alleged species (_Tænia fimbriata_ and _T. capræ_) appear to me more
than doubtful. Unquestionably the common _Tænia expansa_ is capable of
giving rise to severe epizoöty among lambs. The privately communicated
evidence of Professors Brown and Axe, and published evidence supplied
by Messrs Cox and Robertson on this head, are conclusive. Mr George
Rugg has also (in a letter to Prof. Simonds, dated Dec. 4th, 1878)
communicated the particulars of an outbreak in which “large numbers of
lambs perished rapidly” from tapeworms in the intestines, the parasites
varying from one to five or six feet in length. This tapeworm (_T.
expansa_) is also very prevalent in Germany. Ruminants, however, both at
home and abroad, suffer much more severely from bladder-worms. Of these,
_Echinococcus veterinorum_, _Cysticercus tenuicollis_, and _Cœnurus
cerebralis_, are not only shared alike by all varieties of cattle,
sheep, and goats, but they also infest the deer tribe, antelopes, the
giraffe, and even camels. In 1859 I obtained the slender-necked hydatid
from a spring-bok (Gazella). Besides these larval cestodes, cattle
are very liable to harbor measles (_Cysticercus bovis_), whilst sheep
also entertain an armed Cysticercus (_C. ovis_). I cannot again dwell
at any length upon the source of these immature helminths, but I may
remark upon the extreme frequency of measles in Indian cattle. This is
explained by the careless habits of the people. They not only consume
veal and beef in an imperfectly cooked state, but when suffering from
tapeworm no precautions are taken to prevent cattle from having access
to the expelled proglottides of _Tænia mediocanellata_. The subject has
already been dealt with in the first part of this work, and also in my
‘Manual,’ quoted in the bibliography. The mutton measle is described
under the heading of _Tænia tenella_. In like manner I must refer
to the ‘Manual’ for a detailed account of the gid hydatid (_Cœnurus
cerebralis_). How many kinds of Cœnuri exist it is impossible to say,
but I am of opinion that the various polycephalous bladder-worms found
by Rose, Baillet, and Alston in rabbits, by myself in a lemur and in
a squirrel, and by Engelmeyer in the liver of a cat, are referable to
tapeworms specifically distinct from the _Tænia cœnurus_ of the dog.

It was in 1833 that Mr C. B. Rose, formerly of Swaffham, Norfolk,
discovered an undoubted example of polycephalous hydatid in the rabbit,
the parasite in question bearing a very close resemblance to _Cœnurus
cerebralis_. As the accuracy of Rose’s determination respecting the
characters of the hydatid has been called in question, I again invite
attention to the original description as recorded in the ‘London
Medical Gazette’ for November 9th, 1833. At page 206, vol. xiii, of
that periodical, after describing the common _Cœnurus cerebralis_ of
the sheep, Rose writes:--“This (_i.e._ _C. cerebralis_) is the only
species of Cœnurus noticed by authors, but I have met with another. It
infests the rabbit, and I have found it situated between the muscles
of the loins. It is also met with in the neck and back. This hydatid
grows rapidly, and multiplies prodigiously, and being seated near the
surface it soon projects, and sometimes forms a tumour of considerable
magnitude. When the warrener meets with a rabbit thus affected, he
punctures the tumour, squeezes out the fluid, and sends the animal to
market with its brethren. I possess a specimen of this species in a
pregnant state. The earliest visible state of gestation is a minute
spot, more transparent than the surrounding coats of the parent; this
enlarges till it projects from the parietes of the maternal vesicle. It
continues to enlarge until it becomes a perfect hydatid, attached by a
slender peduncle only; even whilst small, other young are seen sprouting
from it, and so on in a series of three or four. My specimen exhibits
them in every stage of growth, from a minute point to a vesicle the
size of a hen’s egg. As I can see no difference in structure between
this hydatid and the last-mentioned (_i.e._ _Cœnurus cerebralis_), I
am unwilling to consider it a different species, for surely a varying
locality ought not to constitute a specific character.”

The observations of Rose did not escape the well-known Dutch
author, Numan. In a foot-note to his memoir, entitled “Over
den veelkop-blaasworm der Hersenen,” he makes the following
observations:--“Rose observes that he has found Cœnurus in bladdery
rabbits (blaaszieke konijnen) in the skin, and in the cellular tissues
of the trunk and extremities. The veterinary surgeon, Engelmeyer, of
Burgau, says he has also found the _Cœnurus_ (Veelkop) in the liver
of a cat (‘Thierärztliche Wochenschrift van 1850,’ s. 192). These
observations differ thus far from those of other writers, according to
whom the Cœnurus is only found in the brain and spinal marrow. However,
it is not impossible in particular cases that some parasites may have
strayed from their ordinary dwelling-places.” Numan seems to have been
not a little puzzled to account for these discrepancies, and he was
altogether undecided regarding the mode of propagation of Cœnuri and
Cysticerci. This will be gathered from the following passage, which I
quote in the original:

“Ik moet het onbeslist laten, of de grondbeginsels, waaruit de wormen
uit de blaas ontspruiten, als wezenlijke of als zoogenaamde kiemen
(_gemmæ_) zijn te houden, waaromtrent de gevoelens der voornamste
Natuuronderzoekers, die zich met de nasporing der blaaswormen hebben
onledig gehouden, nog uiteenloopen. Gulliver, door Rose (a. p. pag. 231)
aangehaald, houdt ze voor eijeren, in den _Cysticercus tenuicollis_, en
Goodsir, mede aldaar genoemd, spreckt ook van _ova_ bij den _Cœnurus
cerebralis_; doch de laatstgenoemde en Busk houden ze voor _gemmæ_.
Hier wordt voots gewezen op Owen en de meeste onderzoekers van den
tegenwoordigen tijd, die het daarvoor houden, dat alle hydatiden zich
alleen door _gemmæ_ reproduceren. Rose merkt voorts aan, dat, hetzij
men de geboorte dezer ingewandswormen toekenne aan eijeren of kiemen
(_gemmæ_), dit om het even is, wat hunne verspreiding (_dissemination_)
betreft, daar zij ingesloten zijn, waardoor de wijze, hoe zij naar
buiten komen en verspried worden, tot dusver een gesloten boek is.”

The idea of Numan that these are strayed forms of _Cœnurus cerebralis_
is not convincing. It must not be forgotten, however, as Leuckart and
Numan have both reminded us, that Eichler discovered an hydatid about
the size of a goose egg in the subcutaneous tissue of a sheep. This
bladder-worm supported nearly two thousand heads. In regard to true
hydatids or acephalocysts in ruminants, on which subject I have already
dwelt at much length, I may again observe that the Hunterian Museum
contains some remarkable examples. In 1854 I obtained Cysticerci from a
giraffe, and I have reason to believe that similar bladder-worms infest
antelopes and deer.

The nematodes of the ruminants are both numerous in, and destructive to,
their bearers, those infesting the lungs being productive of a parasitic
bronchitis termed husk or hoose. In cattle the lung-worm (_Strongylus
micrurus_) is particularly fatal to calves, whilst _S. filaria_ attacks
sheep, and especially lambs. A larger but less common lung strongyle
(_S. rufescens_) is sometimes found associated with the latter. In
1875 I conducted experiments with the view of finding the intermediate
hosts of _S. micrurus_, and I arrived at the conclusion that the larvæ
of this parasite are passively transferred to the digestive organs
of earth-worms. The growth and metamorphoses which I witnessed in
strongyloid larvæ taken from earth-worms (into which I had previously
introduced embryos) were remarkably rapid, and accompanied by ecdysis.
The facts were as follows. About the middle of October, 1875, I received
from Messrs Farrow, of Durham, a fresh and characteristic specimen of
diseased lungs, in which the bronchi were swarming with Filariæ.

In reference to the case itself, Mr George Farrow afterwards informed
me by letter that the calf was one of a herd of seven, whose ages
respectively varied from four to six months. At the time of his writing
(October 20th) the remaining six animals were progressing favorably
towards recovery--a result which Mr Farrow attributes to the employment
of inhalations of turpentine and savin, combined with the internal
administration of tonics. In regard to this plan of treatment, and in
reference to the source of infection, he adds:--“I should have preferred
trying the inhalations of chlorine gas, but as the patients were so
very young and in poor condition, I deemed it advisable to try a milder
course of treatment.

“The history of the case is brief. The cattle are on a very dry and
well-drained farm, but during the summer there was a great scarcity of
water, and they were supplied from a stagnant pool which eventually
became dry. This, in my opinion, is where the disease originated.”

Mr George Farrow’s opinion is probably correct, being in harmony with
the most recent results of scientific research as made known more
particularly by Leuckart. But the facts thus conveyed do not explain
the whole truth; or, rather, they convey it only in a very incomplete
manner. Professor Leuckart’s experiments were made with several
species such as _Strongylus armatus_ of the horse, _S. rufescens_, _S.
hypostomus_, and _S. filaria_ of the sheep, and _S. commutatus_ of the
hare. Still, as regards the strongyles, partial as the results have thus
far appeared, there cannot be a doubt that his successes with several
allied nematode species form a key by which we may yet unlock and expose
to view the entire life-history of that specially obnoxious form under
consideration, namely, _Strongylus micrurus_. To summarise the whole
matter in a few words, Leuckart supposes that all these strongyloids
require a change of hosts before they can take up their final abode
in the sexually-mature state. This he infers especially because their
respective embryos display characters very similar to those exhibited by
_Olulanus_. He believes that either small mollusks or insects and their
larvæ play the _rôle_ of intermediary bearer. His experiments with the
embryos of _Strongylus filaria_ prove that these larvæ can be kept alive
for several weeks in moist earth, and that whilst so conditioned they
undergo a first change of skin within a period varying from eight to
fourteen days. Experiments on sheep, made with these moulting larvæ, led
only to negative results. Unless the following facts be accepted, the
scientific position remains pretty much where Leuckart left it.

On the 22nd of October, 1875, at 1 p.m., I placed the entire
egg-contents of the uterus of a _Strongylus micrurus_ on a glass slide
hollowed out in the centre. Probably something like ten thousand ova
were thus brought under observation, yet only three were noticed as
freed from their shells, probably as the result of accidental rupture.
Two of these displayed lively movements. In round numbers the ova gave
a measurement of 1/300 of an inch in length by 1/750 of an inch in
breadth, whilst the free embryos measured about 1/90 of an inch long,
and less than 1/1000 of an inch in thickness. The integument of the
embryo displayed neither markings of any kind nor any double contour.
The contents of the worm were granular throughout, these granules being
crowded in the centre of the body, but scarcely visible towards the head
and tail, where for a considerable space (fully 1/300″) the worm was
perfectly transparent. No trace of any sexual organs or their outlets
was visible. An examination of numerous eggs and free embryos obtained
from near the primary bronchial bifurcations (of Mr Farrow’s specimen)
yielded the same microscopic results, the only thing worthy of remark
being that the embryos from the mucus seemed much more lively than those
which, as I supposed, had accidentally escaped their shells.

At 1.30 p.m. I placed some free embryos in two watch-glasses, one
containing water and the other saliva, and placed them before the fire.
Being called away professionally I found on my return at 3 p.m. that
evaporation to dryness had occurred in the interval. All my attempts to
resuscitate the embryos by moisture proved unavailing, a result which,
though negative, proves how little capable these embryonic creatures are
of enduring desiccation. If these facts be confirmed, their practical
significance is not without value in relation to the choice of dry
pasturage grounds for the rearing of young cattle. I may add that whilst
half an hour’s immersion of the dried embryos failed to restore any sign
of life, the previous warmth and moisture had caused many more embryos
to escape their shells during the time they were placed before the fire.

At 4 p.m. I passed some very rich mould through muslin. Some of this
finely sifted earth I placed in a watch-glass, adding a little water to
moisten it, and also numerous eggs and free embryos. In a wine-glass and
also in a small jar I placed some coarse earth with water added to make
thin mud, and to both of these I added, not only eggs and embryos, but
also portions of the reproductive organs of the adult female worms.

On the 23rd of October, at 2 p.m., I examined the contents of these
vessels. All the embryos in the vessels containing the coarse earth were
dead, but several were found alive in the watch-glass containing the
fine moist mould. Structurally these latter had undergone no perceptible
change beyond a somewhat closer aggregation of the somatic granules.

Although the embryos in the coarse wet mud had perished, the eggs
with unhatched embryos appeared to have retained their vitality. Of
this fact, indeed, I subsequently obtained abundant proof; and I
also satisfied myself that the death of the embryos had not resulted
either from the coarseness of the earth or from excessive moisture,
but from the presence of numerous shreds of the uterine tubes which I
had somewhat carelessly added to the vessels. Previous experiments,
conducted many years back, had indeed taught me that few if any
nematoid larvæ can resist the fatal action of putrid matter, however
slight the putrescence.

Having removed the offending shreds, I next placed a quantity of living
ova together in the earthenware jar, and allowed the earth-contents to
become much drier by evaporation before the fire. I also left others in
a watch-glass, which was placed under a bell-jar enclosing several ferns.

On the 25th of October I removed particles of the moist earth,
altogether weighing about two grains, and, on submitting them to
microscopic examination, had the satisfaction to observe about a dozen
living embryos, some of which exhibited very lively movements. There
was not the slightest indication of putridity; nevertheless, I noticed
several shreds of the adult worms whose presence had been accidentally
overlooked, and, curiously enough, all the embryos subsequently removed
from the immediate neighbourhood of these decomposing shreds of tissue
were almost motionless and apparently in a moribund condition. On
examining the contents of the watch-glass placed under the fern shade,
I noticed several points of interest. First of all the earth contained
strongyle embryos, such as I had seen before. Secondly, the surface
of the mould was being traversed by three or four briskly-moving
_Thysanuridæ_, hunting about with all that restless activity which Sir
John Lubbock has so well described. Thirdly, in marked contrast to the
behaviour of these I noticed several slow-moving _Acaridæ_, apparently
also employed in searching for food. And lastly, while thus engaged, the
surface of the mould in the centre of the deep watch-glass was suddenly
upheaved, by which I was at once made aware of the presence of another
most welcome and unexpected intruder. In short, an earth-worm had crept
from the dry mould in which the ferns were growing, and had taken up its
temporary abode in the soft moist experimental-earth contained in the
watch-glass. When contracted, this _Lumbricus terrestris_ was barely
an inch in length. On placing it under the half-inch objective glass,
I noticed a single embryonic strongyle adhering to the skin, but not
firmly, and evidently only in an accidental way, so to speak. It was
clear to me that it possessed neither the intention nor the power to
penetrate the chitinous integument of the earth-worm.

Having in the next place removed the _Lumbricus_ with a pair of forceps,
and having washed it under a current of water, I snipped off the
lower end of the body, and allowed some of the intestinal contents to
escape on a clean glass slide for separate microscopic examination.
Immediately, to my satisfaction, I found that the fæcal contents
displayed a large quantity of my strongyle ova, enclosing still living
embryos, and in addition several free embryos presenting characters
which declared that they were from the same source. Clearly they had
been ingested by the earth-worm along with its ordinary food. One or
two of the embryos were conspicuously larger than their fellows, but
the structural changes they had undergone were not so marked as to
lead me for a single moment to associate them with any of the various
sexually-mature worms which have been described as normally infesting
the earth-worm. I had no doubt whatever that such slight structural
changes as were now discernible had resulted from growth and development
consequent upon this accidental admission into the body of the
intermediate bearer which might or might not prove to be its legitimate
territory. It will be seen that subsequent observations tended to
affirm the truth of this view. I made a careful examination of one of
these larvæ, whose active movements were such as to render the process
exceedingly tedious. The earth-worm itself (or rather its unequal
halves) was placed in a fresh watch-glass containing ordinary mould. The
larvæ or embryos obtained from the earth-worm now measured about 1/80 of
an inch in length, their heads exhibiting a short and simple chitinous
buccal tube, whilst their tails were somewhat more pointed and bent
upward. The somatic granules were more crowded, rendering the position
of the intestinal tract more marked, though, as yet, the differentiation
gave no indication of the formation of a distinct intestinal wall. There
was no perceptible increase of thickness of the body of the embryos.
The results thus far naturally encouraged me to procure some fresh
earth-worms for experimental purposes.

On the 26th of October I found that the halves of the earth-worm were
alive, and I left them undisturbed in rather dry mould, freshly added.
To a watch-glass containing newly sifted earth and embryos I added a
fresh garden-worm, which was rather sluggish from the cold; and in
the original jar I placed another smaller and very active earth-worm
obtained the same morning. Finding the soil in the jar congenial,
this _lumbricus_ soon buried itself. Another and larger earth-worm
subsequently added refused to follow this example. It was therefore
removed from the jar. Believing the fine and artificially prepared
soil to be still much too moist, I caused further evaporation; and I
afterwards found that the thicker the mud the more suitable it proved as
a residence for embryonic nematodes and earth-worms alike.

On the 27th I found the small earth-worms in the jar burrowing freely
and throwing up fæcal casts. From one of my watch-glasses the worm
had escaped, its place being occupied in the meantime by an actively
crawling _Julus_. I put a second _Julus_, obtained from the mould in the
fern jar, to form a companion (in view of other experiments), and I also
added a fresh earth-worm, covering all by another inverted watch-glass,
which I thought would prevent their escape.

In the next place I examined the halves of my original experimental
earth-worm. They were scarcely capable of motion, but retained a certain
amount of vitality. The tail was the more active half, and unfortunately
it was soon afterwards lost. Carefully washing the superior half, and
transferring its contents to a glass slide, I immediately detected
under the microscope a large number of embryos. They were in a state of
marked activity, the largest having increased to about 1/50″ of an inch
in length, whilst their structure had become correspondingly advanced.
Here, again, there was no room for doubt as to their source, especially
as they individually displayed different degrees of organisation, all
answering to one and the same embryonal type. I now observed a distinct
œsophagus, the rest of the intestinal tract being still more conspicuous
than heretofore, though, as yet, no true cells marked the limitation of
the stomach and chylous intestine.

After an hour’s immersion in cold water some of the larvæ became much
less active, whilst others were motionless, so that I feared all were
about to perish. In the hope of keeping a few of them alive I now added
to the slide some finely sifted grains of mould, placing the slide under
a small bell jar which protected some of my ferns. The remains of the
moribund earth-worm were also covered with mould.

Other larvæ, derived from the earth-worm, were placed on the moist pinnæ
of a living fern-frond which supported small drops of water, for by
this process I hoped in some measure to imitate the dew which naturally
condenses on the grass and fodder of our low-lying fields. At 3.15 p.m.
of the same day (27th) I also examined a fresh worm pellet from the jar,
and found it to contain living strongyle embryos, which as heretofore
had not exhibited the slightest advance either in respect of size or
structure.

At noon on the 28th I again sought for the larger larvæ, first of all on
the slide covered with fine earth, and afterwards within the remains of
the upper half of the original earth-worm. On the slide I could detect
none, but within the intestine of the worm there were still two living
larvæ left, whose characters corresponded precisely with the largest
that I had previously obtained from the same source only the day before.
They had undergone, however, no further change in structure, and their
measurements remained precisely the same.

At 12.30 p.m. I snipped off two or three of the terminal fern-fronds
on which I had placed a few advanced larvæ. On examination under the
half-inch objective I immediately detected one of the larvæ cruising
about most actively. On adding a drop of water it soon rushed across
the field of the microscope, its movements being thoroughly eel-like.
The size of this larvæ had so much increased that it was now visible to
the naked eye, measuring, indeed, as much as 1/30 of an inch from head
to tail. Moreover, its organisation had advanced in a marked degree.
Thus, the digestive organs were better defined, and on one side of them
there appeared a regularly arranged congeries of cellules, forming the
commencement of the reproductive organs. As yet, however, I could not
pronounce as to the sex.

At 1.45 p.m. I again examined a few grains of earth from the jar, when
I at once noticed five or six active embryos whose structure failed
to show the slightest advance upon that originally described. It was
evident that the jar contained thousands of them; and since no ova were
found, it became probable that all their embryonic contents had escaped
to swell the number of free larvæ, leaving their very delicate envelopes
to perish. I think I had hit upon the most suitable degree of moisture
favorable to this result.

In the next place I sought for the earth-worm that had been placed
in the infested soil between two watch-glasses. It had escaped. This
obliged me to transfer the mould to a rather wide-mouthed and open
phial, in which four more fresh lumbrici were placed. I feared the
closing of the bottle would be detrimental.

Later in the day I selected an earth-worm which had not been exposed
to strongyle infection, but which was in a moribund condition. In the
intestine there were several free nematoids and also several psorosperms
of the genus _Monocystis_, so well illustrated by E. Ray Lankester. As
to the nematoids, which were filariform, they neither corresponded in
size nor structure with my strongyle embryos.

At 1 p.m. on the 29th I renewed my examination of the larva removed
from the fern-pinnule. It showed a further stage of growth, the male
character of the reproductive organs having become apparent. The now
tolerably well-formed vas deferens had pushed the chylous intestine on
one side, whilst a series of caudal rays, five on either side, supported
two narrow membranous wings, which represented the lateral lobes of the
hood of the adult strongyle.

At 1.30 p.m. I submitted the intestinal contents of four fresh
earth-worms removed from my garden to microscopic examination, but no
nematoids were found in any one of them.

About 2 p.m. I removed another large and active strongyle larva that had
been reared on another fern-pinnule. It was of the same size as that
previously described, but was in the act of changing its skin. It was
then put aside along with the other worm under the glass shade.

At 3 p.m. I intended to have examined one or more of the earth-worms
placed in the open-mouthed phial, but all had escaped and buried
themselves in the fern-mould out of reach.

At noon on the 30th I renewed my examination of the two large larvæ
whose developmental changes I had been instrumental in producing from
the time of their escape from the egg-coverings. I saw no reason to
doubt that the sequence of changes thus far noticed referred to the
species of parasite under consideration. Both larvæ were active, but the
moulting one had now completed its ecdysis. Its sexual distinctiveness
had become yet more pronounced by the formation of two rather short
and stout spicules, the point of the tail displaying a very minute
awl-shaped projection. The lateral membranes had not visibly increased
in size. One of these larvæ, the first under observation, now perished
from the injuries sustained during inspection.

Again, and later in the day, I sought to clear up any doubts that might
still suggest themselves respecting the source of these larvæ, by once
more submitting the intestinal contents of two fresh and uninfected
earth-worms to careful scrutiny. In the first worm no parasite could be
found, and in the second only one minute nematoid; its organisation,
which was sexually incomplete, neither corresponded with my strongyle
embryos, nor, so far as I could judge, with Goeze’s _Ascaris minutissima
microscopica_ (the _Anguillula lumbrici_ of Diesing and others), nor
with Dujardin’s _Dicelis filaria_. It was a very long and narrow
creature, but I lost it whilst attempting to secure an accurate
measurement. I should say it was about 1/50th of an inch in length, and
not more than 1/1500th in breadth. I made a rough outline sketch of it.

In view of further observations I now placed five more earth-worms in
the jar containing strongyle embryos, and I also placed six others in
the phial which contained coarser mould, and only a comparatively small
number of the original strongyle embryos. The phial was closed with
a cork and half buried in the fern-mould of one of my larger Wardian
fern-pans. Before this transfer was made I again took an opportunity
of ascertaining by microscopic evidence that the embryos lodged in the
coarse and fine mould had none of them made the slightest advance in
organisation. The worms placed in the jar immediately proceeded to bury
themselves.

At noon on the 1st of November I sought to get further results from the
only large free larva which now remained to me (for the fern-pinnules
on which the larvæ were originally placed had dried up and no third
specimen could be discovered). Structurally the larva presented no
advance. It therefore appeared to me necessary to place it under new
conditions in view of exciting further progress towards sexual maturity
and adult growth. To transfer it to the bronchus of a living calf would,
of course, have been the crucial experiment, but the hopelessness of
getting any satisfactory result from this solitary transfer deterred me
from the attempt. On a larger scale, with many larvæ, a positive issue
would of course prove decisive. Accordingly, the only thing I could
do, in partial imitation of nature, was to try and induce some further
changes by placing the larva in human saliva, kept warm artificially. As
a first step I immersed the creature in a little of the secretion added
to the glass slide, when it immediately displayed very lively movements,
such as could only be fitly described as frantic. This encouraged me
to replace the slide under one of the fern shades without applying any
additional heat. I then left it.

At 12.30 p.m. I selected three of the eleven worms lodged in the
infested earth, namely, two from the jar and one from the closed phial,
and made a microscopic examination of their respective intestinal
contents. In one of the worms from the jar I found several embryos
clearly referable to my strongyles, their structure showing scarcely
any advance upon that exhibited by the embryos in the mould itself.
The weather was now excessively cold and the larvæ were motionless;
nevertheless, the application of warmth showed that they were by no
means dead. The fæcal matter obtained from the worm that had lived in
the phial displayed an immense number of infusoriæ (_Bacteria_) which
rushed about rapidly over the field of the microscope. No other signs of
life were detected.

On the 2nd of November I found my solitary strongyle larva alive, but
its movements, though active, were by no means so active as on the
previous day. No fresh structural changes had occurred.

At noon on the 3rd the larva at first lay almost motionless in the
now thick and ropy saliva; nevertheless, on applying a thin glass
cover its movements became tolerably vigorous. During its quiescent
state I succeeded in getting a good view of the caudal rays and other
imperfectly developed organs, of which I retain figures.

Having now satisfied myself that other new conditions were necessary to
enable the larva to arrive at sexual maturity, I sought to transfer it
to a glass tube filled with fresh saliva. This transfer was a matter
of difficulty. After passing the thick ropy saliva into the tube, I
examined the slide and found that the larva was gone. I concluded it was
in the tube, which, in order to keep the contents warm, I subsequently
carried about concealed in my under-clothing during the day and placed
in my bed during the night. This increase of temperature, however,
caused decomposition of the saliva; so when next day I diligently sought
for my experimental nematode it was nowhere to be found. Thus terminated
my observations on the first set of embryos, which had enjoyed their
temporary sojourn in the intestinal tract of the earth-worm, and which
had certainly afterwards undergone a series of marked structural and
morphological changes, accompanied with ecdysis.

The weather had now been for several days exceedingly cold, but on the
4th a favorable change set in, which led me to hope that I might be
able to verify the facts above recorded. Accordingly, as a new point of
departure, I re-examined the fine mould, and at once found my embryos
in a high state of activity. The mould, however, appearing too moist
for the earth-worms, I permitted further evaporation before closing
the jar with a glass cover. Four days subsequently I examined the
intestinal contents of two of the earth-worms. In one of these, an inch
in length, no parasite of any kind could be detected; but in the other,
which was beyond three inches in length, there were numerous _Opalinæ_
besides several strongyle embryos, the latter presenting characters not
visibly in advance of those still living in the mould. All of them were
motionless, as if they had not got over the shock produced by previous
cold. Moreover, the weather had again become cold, and thus, when I
again inspected my experimental embryos living in the jar, I also found
them motionless, so different from their behaviour on the 4th. However,
since a further result with the earth-worm embryos appeared possible, I
placed some of the fæcal matter, already ascertained to contain a few
of them, on the fronds of a thoroughly moist and dew-covered _Asplenium
bulbiferum_. This plant was in a fern-pan which had the advantage of
considerable fire-warmth during the day. When, however, on the 15th
of November, I examined the fæcal earth removed from several of the
pinnules, I failed to find any of the embryos. Possibly they had
wandered, for the entire frond was covered with dew-drops, which was not
the case with the fern that I had previously experimented on with such
satisfactory results. At all events, whether they had wandered or had
perished, their apparent absence in no way affects my previous record;
and the more so since only a few had been observed in the fæcal matter.
The smallness of the number found in the earth-worm was also readily
accounted for. Thus, when at 1.30 p.m. on the 15th I made a diligent
search for embryos in several grains of the fine mould, not a single
young strongyle could be detected. Possibly the frost of the previous
night had killed them. The earth-worms were still alive and in good
condition.

In conclusion, I may observe that every experimenter with helminths
is well aware how unfavorable the winter season is for this kind of
research. If a repetition of this inquiry in the spring or summer should
confirm these results, it will prove a clear and substantial addition
to our knowledge of the development of the strongyles. Meanwhile, I
think that the data above given render it highly probable that the
larvæ of the hoose-producing strongyle (_S. micrurus_) are passively
transferred to the bodies of setigerous annelids, which are thus
called upon to act as intermediate hosts. If this be so, it is further
certain that important structural changes with ecdysis follow after
their escape from the earth-worms or other annelids, moisture, dew, or
water being essential to the penultimate stage of growth. Final passive
transference, either with fresh fodder from swampy grounds, or, it may
be, from pond water, ultimately enables them to acquire their definite
sexual form, size, and other adult characteristics.

According to Mégnin it is not the _Strongylus filaria_, but a hitherto
unknown and totally distinct species (_Strongylus minutissimus_)
which occasions pneumonia in Algerian sheep. In England the parasitic
bronchitis affecting sheep is generally called the “lamb disease.”
This is unfortunate, because many other parasites prove destructive to
lambs. One of the most injurious species is _Strongylus contortus_,
infesting the true stomach, whilst _S. hypostomus_, occupying the
small intestines, is almost equally obnoxious to the ovine bearer. By
Leuckart and others this last-named worm is retained in Dujardin’s genus
_Dochmius_, in which genus another species occurs (_D. cernuus_). This
worm is quite distinct, but not readily distinguishable by the naked eye
alone. It occasionally occupies the upper part of the colon, as well as
the lower end of the small intestine. A rarer intestinal worm in lambs
is the _Strongylus filicollis_. Several other strongyles infest the ox
(_S. radiatus_, _S. inflatus_, _S. gigas_), goat (_S. venulosus_), and
stag (_S. ventricosus_).

As showing the extraordinary prevalence and destructiveness of entozoa
in certain countries, I will adduce an instance in which my opinion
was requested and given some five years since. My informant stated the
case somewhat in the following manner:--On a farm in New South Wales,
and lying about 200 miles to the north-west of Sydney, on the Trafalgar
tributary of the Macquarie river, out of a flock of about 8000 sheep no
less than 1200 have perished. In many instances post-mortem examinations
were made, _worms_ appearing in all cases to be the cause of death.
There were four kinds of parasites present. The most numerous were
red and white, “marked like a barber’s pole.” These occurred chiefly
in the fourth stomach and commencement of the duodenum, but some were
found throughout the entire length of the small intestine. A second
set comprised small black worms, resembling needles, scattered only
in the lumen of the intestines. The third set were tapeworms, each
being several fathoms in length. The fourth set was made up of white
threadworms, individually measuring two inches in length. These occupied
the bronchial tubes, and were characterised by my informant as “the
most deadly of all.” Without the aid of specimens I at once recognised
these brief diagnostic characters as severally referring to _Strongylus
contortus_, _Dochmius hypostomus_, _Tænia expansa_, and _Strongylus
filaria_.

What the inquirer desired at my hands was “full information respecting
the general principles to be carried out in view of the prevention of
this parasitic disease, regard being had to the difficulty of finding
any food but pasture, to the number of animals to be treated, and to
the not unfavorable circumstance that the run is divided by fencing
to a great extent.” I was also requested to explain the best modes of
treatment, being at the same time informed that turpentine drenchings
had already been employed with only “partially effective” results. I
was also expected to give numerous and varied formulæ, to be tried in
succession, supposing the first should fail. Of course, it should have
been known that I neither prescribe medicines nor accept fees in respect
of animal patients; but, as in this instance my opinion was permitted
to assume the form of a “written scientific report,” I was pleased to
have an opportunity of commenting freely and fully on the significance
of the facts submitted. My advice took the form of a long report, which
might here be usefully given _in extenso_ were it not somewhat of the
nature of a private and privileged communication. I have no doubt that
the stockowner would be pleased that I should utilise his remarkable
“case” for the benefit of agriculturists and others; but it is for him
to publish the “opinion” as it stands, should he think fit to do so.

Practical men, on reading the few foregoing particulars, will perceive
that one of the principal obstacles to success in cases of this kind
lies in the circumstance that artificial food can only be procured with
difficulty. Where the source of the disease is associated with the
pasture-supply, any treatment, however effectual for a time, can only be
followed by partially satisfactory results.

The destructive powers of any one of the above-mentioned parasites being
sufficient to produce a fatal lamb-disease, it is clear that when two
or more of these particular species attack their victim in considerable
numbers, the ovine-bearer has little chance of recovery. The intestinal
strongyles, by means of their oral armature, behaving as veritable
leeches, will, if not expelled in good time, produce a rapidly fatal
anæmia, precisely in the same way as the human _Anchylostomum_ of the
tropics.

The worst of dealing with this sheep-parasite is that it will not
succumb to ordinary doses of salines like the stomach strongyle;
moreover, the little leech-like wounds will probably bleed after the
parasites have been compelled to abandon their hold. Prevention is
better than cure. Accordingly, I sought to explain the origin of these
creatures, and in what possible ways the germs of the various species
could be destroyed, or at least limited in numbers.

As to the drugs and inhalations to be employed, it would be difficult to
advise any more effective than those commonly in vogue, the great thing
being to effect changes of pasture and ground, to look to the purity
of the water-supply, and to supply the best kinds of nourishment after
active treatment. The diseased animals should, from the very first, be
separated from their companions, because the amount of germ distribution
is thereby greatly lessened. They should be at once drenched or treated
by inhalation (as the parasitic nature of the attack requires), and the
enclosure in which the animals have been temporarily housed should be
thoroughly scoured with boiling-hot water impregnated with salt.

The nomenclature of the parasitic diseases of animals is excessively
vague. Thus, _apropos_ to the case above recorded, I may mention that
an American veterinary practitioner appeared to be much shocked that
I should have had the temerity to speak of four distinct kinds of
lamb-disease. It is in this way that practical men often commit serious
mistakes by rolling together disorders that are totally distinct. If
it were true that epizoöty in lambs is exclusively due to _Strongylus
filaria_, then professionals might aptly speak of the parasitic
bronchitis of young sheep as lamb-disease; but we now know that several
other helminths prove terribly fatal to lambs, occasioning death in
totally different ways. In one set of cases the animals are asphyxiated;
in another set they become fatally anæmic; and in a third set they
perish from the severity of nervous reflex irritations. Lastly, it may
be remarked that, in view of the successful management of the parasitic
disorders of animals, the veterinary practitioner must necessarily be
guided by the same general principles as the physician. For myself, I
may say that I have hitherto designedly withheld many practical hints
which a long experience with human patients suggested, not wishing to
appear to dictate to those who are constantly seeing animals. However,
since (contrary to my own wishes) it has happened that both professional
men and agriculturists have not only invited me to give opinions, but
have, at various times, asked me to prescribe, it seems there can have
been no impropriety in publishing my views on this subject. Certainly I
have had no professional motives to serve.

Of the few non-strongyloid nematodes, one of the commonest is
_Trichocephalus affinis_. I have obtained this worm from the giraffe,
and the parasite may be said to infest all ruminating animals, not
excluding even the camels and llamas. As before remarked, the whipworm
has been known to produce severe symptoms in man, and it occasions
“scour” in the sheep. The eyes of cattle are occasionally infested by
_Filaria lacrymalis_ and _F. papillosa_. The last named is the common
eye-worm of the horse. On Feb. 27th, 1875, Dr Edward L. Moss, of H.M.S.
“Alert,” brought me three examples of a nematode which I referred to
_Filaria terebra_. Dr Moss obtained these parasites in 1874, during the
time that he had charge of the Naval Hospital at Esquimalt, Vancouver’s
Island. They occupied the abdominal cavity of the black-tailed deer
(_Cervus columbianus_). The worms were mostly found lying amongst the
coils of the small intestine. They were not attached to the peritoneal
membrane. Dr Moss had shot seventeen deer in all, the males and females
being in about equal proportion; nevertheless, not one of the bucks
showed any trace of the presence of these entozoa. This absence of
parasites in the male deer is noteworthy. Hitherto the worm appears to
have been observed in the red deer (_C. elaphus_), and by Natterer in
three species of American roe (_C. rufus_, _C. simplicicornis_, and
_C. nambi_). Two of the worms measured each about 2-1/3″ in length,
the third exceeding 3″. They displayed in profile two prominent oral
papillæ. Probably there were four of these processes, such as Dujardin
described in his _Filaria cervina_, which, according to Diesing, is a
synonym. They all possessed spirally twisted tails.

Amongst the arachnidan parasites of ruminants having entozoal habits are
_Pentastoma denticulatum_ and _P. constrictum_. The former larval worm
is excessively common in cattle, sheep, deer, and antelopes. According
to Rhind, the adult worm (_P. tænioides_) also infests the sheep. The
_P. constrictum_ has hitherto only been found in the giraffe. On the
10th February, 1859, I obtained numerous examples (_P. denticulatum_)
from a bubale (_Antilope bubalis_) which died at the Zoological
Society’s Gardens. The greater number occupied the surface of the lungs
and intestines; some few, however, were enclosed in cysts beneath the
pleura. In the spring of 1860 I also procured several specimens from the
abdomen of a cape guevi (_Cephalopus pygmæus_).

The ectozoa of ruminants have received much attention, but I can
merely indicate the known forms. Following Mégnin’s classification
we have three well-marked varieties of the acarine genus _Sarcoptes_
(_S. scabiei_, var. _ovis_, var. _capræ_, and var. _cameli_), two
varieties of _Psoroptes_ (_P. longirostris_, var. _bovis_ and _ovis_),
and _Chorioptes spathiferus_. This last is the true mange mite of the
ox (or _Symbiotes bovis_ of Gerlach). A variety of the follicle mite
infests the sheep (_Demodex folliculorum_, var. _ovis_). Numerous
species of tick (_Ixodidæ_) have been more or less fully described.
Of these we have the Carapartos of the Portuguese (_Ixodes bovis_),
attacking cattle; the _I. reduvius_, attacking sheep; the _I. plumbeus_,
said to attack lambs; the _I. albipictus_ and _I. unipictus_, found
on the moose-deer. Probably this species also attacks cattle. A
most horrible arachnidan is found on camels. I allude to _Galeodes
araneoides_ belonging to the _Solpugidæ_. This parasite will bite
severely any person who attempts to dislodge it from the bearer.
Turning to the insects, we find ruminants liable to be annoyed alike
by flies (_Diptera_), fleas (_Aphaniptera_), and lice (_Hemiptera_).
Various species of four different families of flies are apt to prove
troublesome. Of the _Œstridæ_, attacking the ox, we have _Hypoderma
bovis_, whose larvæ form tumours or warbles on the back; also _H.
lineata_, _Dermatobia noxialis_, and _Cephenomyia bovis_ (mihi). The
larvæ of the latter reside at the root of the tongue and adjacent parts.
In the sheep we have _Œstrus ovis_, _Œ. purpureus_, and _Hypoderma
lineata_. Various species also attack goats and antelopes. Dr Kirk
presented me with specimens of Œstrus from the frontal sinuses of a
harte-beest or caama, and they have also been obtained from the sassabe,
the saiga or colus, from the gnoo, and from the brindled gnoo, kokoon
or gorgon. Mr Charles Danford presented me with several bots from an
ibex. One or more species of _Hypoderma_ have likewise been removed from
the gazelle and other antelopes. The deer tribe are much attacked by
bots. In the red deer we have _Hyp. actæon_ and _H. diana_, a species
also infesting the elk. The throat-grubs are _Ceph. rufibarbis_ and
_Pharyngomyia picta_; another species, also occurring in the fallow
deer, _Ceph. ulrichii_, infests the elk, and _C. stimulator_ the roe,
the last-named deer being also infested by _Hyp. diana_. A throat-fly
infests the reindeer, which is also frequently attacked by _Hyp.
tarandi_. Specimens of the latter worm have been obtained by Dr Murie
at the Zoological Gardens. The Hunterian Museum also contains these and
other species of bots, presented by myself in Mr Andrew Murray’s name.
A subcutaneous bot has been found in the musk-deer. A throat-bot (_C.
maculata_) infests the dromedary.

In regard to the so-called free dipterous parasites and other noxious
insects that attack ruminants, their name is legion. One of the worst
is the tsetse (_Glossina morsitans_), immortalised by Livingstone.
Of the _Muscidæ_ we have the ox-fly (_Musca bovina_), the sheep-fly
(_M. cæsar_), and the executioner (_M. carnifex_). Of the _Tabanidæ_
we have _T. bovinus_ and _T. autumnalis_, _Chrysops cæcutiens_, and
the allied _Asilus crabroniformis_ (_Asilidæ_). Amongst the specially
noxious insects must also be placed _Stomoxys calcitrans_ and _Rhagio
columbaschensis_. This fly proves fearfully destructive to cattle in
Hungary and Servia. Lastly, I can only further mention the common
_Melophagus ovinus_. This is nothing more than a gigantic louse, which
from long use agriculturists and veterinarians persist in calling
the sheep-tick. It belongs to the _Hippoboscidæ_, the members of
which family only attack quadrupeds and birds. As regards the lice
(_Anoplura_), I have to mention _Hæmatopinus vituli_ of the calf,
_H. eurysternus_ of cattle, and _H. stenopsis_ of the goat; also
_Trichodectes scalaris_, _T. sphærocephalus_, and _T. capræ_. These
infest the ox, sheep, and goat, respectively.

For some account of the protozoal parasites (_Psorospermiæ_, &c.)
infesting the flesh of ruminants I must refer the reader to Book I,
Section IV, Part VI of this treatise.

BIBLIOGRAPHY (No. 49).--(Anonymous), “On the Hydatid in the Brain of
Sheep,” from ‘Journ. de Méd. Vét.,’ in ‘Veterinarian,’ vol. xxviii, p.
461, 1855.--(_Idem_), “Note on the ‘Rot in Sheep,’” ‘Veterinarian,’
vol. xxxvi, p. 100, 1863.--(_Idem_), “On the Hydatid, or Tumour of the
Brain (of Sheep),” under sig. of “Ben Ledi,” in ‘Veterinarian,’ vol.
xii, p. 467, 1839.--(_Idem_), “Note on Rot in Sheep, Cattle, and Hares,”
from the ‘Bristol Mirror and Scotsman,’ in ‘Veterinarian,’ vol. xxxvi,
pp. 156-7, 1863.--(_Idem_), “Tapeworm Epizoöty in Nottinghamshire,”
‘Brit. Med. Journ.,’ 1858.--(_Idem_), “Prevalence of Rot in Sheep,” from
‘Carlisle Journ.,’ in ‘Edin. Vet. Rev.,’ 1863.--_Baillet_, “Filariæ in
the Eye of an Ox,” from ‘Journ. des Vét. du Midi,’ in ‘Veterinarian,’
vol. xxxi, p. 703, 1858.--_Barnett, J._, “Hydatids in the Liver of a
Cow,” &c., ‘Veterinarian,’ 1865, p. 236.--_Beale, L. S._, “On Entozoa
(?) in the Muscles of Animals destroyed by the Cattle Plague,” ‘Med.
Times and Gaz.,’ Jan. 20, 1866, p. 57; see also “Annotation,” ‘Lancet,’
Jan. 13, 1866, p. 45, and ‘The Microscope in Medicine,’ 4th edit.,
1878.--_Beneden_ (see Van Beneden).--_Böllinger, O._, “_Echinococcus
multilocularis_ in der Leber des Rindes,” ‘Deutsch. Zeitschr. f. Thier
med.,’ ii, 1876, s. 109.--_Brauer_ (see Bibl. No. 50).--_Bugnion, E._,
“Sur la pneumonie vermineuse des animaux domestiques,” ‘Compt. Rend. de
la réunion de la Soc. Helvet.,’ Andermatt, 1875.--_Chaignaud_, “Worms
in the Eyes of Oxen (with remarks by Desmarets),” from the French,
in ‘Veterinarian,’ vol. i, p. 77, 1828.--_Cobbold_, “Descr. of a new
Trematode from the Giraffe,” ‘Rep. of Glasgow Meeting of Brit. Assoc.,’
1854, and in ‘Edin. New. Philosoph. Journ.,’ 1855.--_Idem_, “On Flukes,”
‘Intellectual Observer,’ Feb., 1862.--_Idem_, “The common Liver Entozoon
of Cattle,” _ibid._, March, 1862.--_Idem_, “The Whipworm of Ruminants,”
_ibid._, Dec., 1863.--_Idem_, “Parasite-larvæ,” _ibid._, March,
1863.--_Idem_, “On the Measles of Cattle and Sheep” (see various papers
quoted in Book I, Bibl. No. 13).--_Idem_, “On the Cattle-Plague Bodies
(spurious Entozoa),” see Bibl. No. 41.--_Idem_, “On the Fluke Parasites
of our Food-producing Ruminants,” Lect. iv of the Cantor series, pub.
in ‘Journ. Soc. Arts,’ 1871.--_Idem_, “Remarks (&c.) in ref. to the
Management of Sheep suffering from Nematoid Worms,” ‘Veterinarian,’
Oct., 1876.--_Idem_, “Record of preliminary Experiments with the Eggs
and Embryos of the Husk-producing Strongyle of the Calf,” _ibid._, Dec.,
1875.--_Idem_, in ‘Entozoa,’ pp. 145-183; also in ‘Manual,’ and in the
chap. on “Parasitic Diseases” contributed to ‘Williams’ Principles
of Vet. Med.’--_Idem_, “Remarks on Prof. Perroncito’s Researches,”
‘Veterinarian,’ Dec., 1877.--_Idem_, ‘Amphistomes of the Ox,’ see
Bibl. No. 51.--_Cooper, J._, “Three Cases of Cœnurus in Calves,”
‘Veterinarian,’ 1865, p. 357.--_Copeman, A._, “Hydatids in the Brain
of Lambs,” ‘Vet. Record,’ vol. iii, p. 337, 1847.--_Cox, W._, “Tænia
in Lambs,” ‘Veterinarian,’ vol. xxviii, p. 446, 1855.--_Creplin_, fig.
of _Amphist. crumeniferum_, in ‘Wiegmann’s Archiv,’ 1847, tab. ii, s.
30.--_Crisp, E._, “On the ‘Lamb-disease,’ of which Parasites in the
Lungs are generally the Cause or Consequence,” repr. from ‘Journ. of
Bath and West of England Soc.,’ in July to October Nos. of ‘Edin. Vet.
Rev.,’ 1863.--_Idem_, “Note on _Str. filaria_,” ‘Proc. Zool. Soc.,’
1856.--_Danford_ (see Cobbold, Bibl. No. 52).--_De Reck_, “On the
Draconcule (_Strong. filaria aut veinulosus?_) of Lambs,” from ‘Ann.
de Logelin,’ in ‘Veterinarian,’ vol. v, p. 521, 1832.--_Dupleune_,
“Hydatids in the Brain of an Heifer,” from ‘Mém. de la Soc. Vét. du
Calvados,’ in ‘Veterinarian,’ vol. ix, p. 115, 1836.--_Dupuy_, “An
Hydatid in the Lumbar portion of the Spinal Marrow of a Lamb, aged
eighteen months,” from ‘Journ. Théorique et Prat.,’ in ‘Veterinarian,’
vol. iv, p. 285, 1831.--_Engelmeyer_, ‘Thierärztliche Wochenschrift,’
1850, p. 191.--_Findeisen_, “Ech. in der Lunge,” ‘Repert. f.
Thierheilkund,’ 1875, s. 48.--_Fry, J._, “Worms in the Trachea (of
cattle),” ‘The Hippiatrist,’ vol. iii, p. 5, 1830.--_Furstenberg_, “On
_Pent. tænioides_ of the Sheep,” ‘Edin. Vet. Rev.,’ 1863.--_Gamgee, J._,
“On Parasitic Diseases,” extr. from his ‘Rep. to the Privy Council,’
‘Edin. Vet. Rev.,’ Dec., 1863.--_Idem_, “On Cattle Diseases (including
those produced by Entozoa),” from letters in the ‘Times’ of Oct.
22, Nov. 10 and 13, &c.; in ‘Edin. Vet. Rev.,’ Dec., 1863.--_Idem_,
“On Diseased Meat (especially in relation to Trichina),” ‘Pop. Sci.
Rev.,’ Jan., 1864.--_Idem_, “On Sturdy in Sheep (with figs. from Van
Beneden, Leuckart, and Cobbold),” ‘Edin. Vet. Rev.,’ vol. i, p. 440,
1859.--_Idem_, “Gleanings from the Researches of Eschricht, Haubner, A.
Thomson, &c., respecting the Origin and Development of the Entozoa,”
‘Veterinarian,’ 1855.--_Giacomini_ (see Bibl. No. 13).--_Gulliver_,
“On the Structure of the Entozoa belonging to the genus Cysticercus,”
‘Med.-Chir. Trans.,’ ‘Lond. Med. Gaz.,’ and ‘Lancet,’ 1840-41.--_Idem_,
“Notes on the Ova of _Dist. hepaticum_, and on certain Corpuscles
obtained from the genus Cysticercus,” ‘Proc. Zool. Soc.,’ March, 1840,
and in ‘Ann. Nat. Hist.,’ vol. vi, 1841; also ‘Month. Journ. Med.
Sci.,’ vol. ii, 1842, and ‘Micros. Journ. and Struct. Rec.,’ p. 95,
1842.--_Hewlett_ (see Bibl. No. 13).--_Holmes, J._, “Filaria in the
Bronchi of a Calf,” ‘Vet. Rec.,’ vol. i, p. 125, 1845.--_Hunter, J._,
“Ileum of a Ruminant containing Acephalocyst Hydatids;” see description
of preparation No. 863 in the ‘Catalogue of Mus. Roy. Coll. Surg.
Lond.’ (“Pathology,” vol. ii, p. 201), 1847.--_Idem_, “Hydatid in the
Humerus of an Ox” (_ibid._, prep. No. 864).--_Idem_, “On Hydatids of
the Sheep,” in supp. to his paper on ‘Human Hydatids,’ in ‘Trans. of
Soc. for the Improvement, &c.,’ vol. i, 1793, p. 34.--_Huxley_, “On
the Anatomy and Development of Echinococcus (from a Zebra),” ‘Proc.
Zool. Soc.,’ and ‘Ann. Nat. Hist.,’ 1852.--_Karkeek, W. F._, “Notes
on the _Rot_ (or _iles_ of the Cornish graziers),” ‘Veterinarian,’
vol. iv, p. 573, 1831.--_King, E._, “On the Propagation of Rot (by
means of the eggs of _Fasc. hepatica_) in Sheep,” ‘Veterinarian,’ vol.
ix, p. 95, 1836.--_Krabbe_, “Husdyrenes Indvoldsorme,” ‘Tidsskrift
for Vet.’ (See also my notice of the memoir in ‘Lond. Med. Rec.’ for
1872; repr. in ‘Veterinarian,’ May, 1873.)--_Küchenmeister_ (see Bibl.
No. 13).--_Leaver, T._, “Cases of the Husk (from worms) in Cattle,”
‘Veterinarian,’ vol. ii, p. 355, 1829.--_Lepper_, “Hydatids in the
Kidney of a Lamb (with remarks by Prof. Varnell),” ‘Veterinarian,’
vol. xxxvi, p. 524, 1863.--_Lewis_ (see Bibl. No. 13).--_Lord, J._,
“On some of the Parasites principally affecting Ruminants,” ‘Trans.
Vet. Med. Assoc.,’ 1842-43.--_Masse_ (see Bibl. No. 13).--_Mayer,
T._, “On Hoose in Cattle (from Filaria),” ‘Veterinarian,’ vol. xiii,
p. 227, 1840.--_M’Call, J._, “On Sturdy in Sheep,” _ibid._, vol.
xxx, p. 267, 1857.--_Mégnin, P._, “Le _Str. minutissimus_,” ‘Bullet.
de la Soc. Centrale Vét.,’ in ‘Rec. de Méd. Vét.,’ July, 1878, and
in ‘Ann. de Méd. Vét.,’ Oct., 1878, p. 563.--_Moorcroft_, “Brain
Hydatids,” ‘Med. Facts and Observ.,’ 1792.--_Morton, W. J. T._, “On
the Entozoa affecting Domesticated Animals, and particularly on _Fasc.
hepatica_ or Liver Fluke in Sheep,” ‘Veterinarian,’ vol. xii, p. 735,
1839.--_Mosler_ (see Bibl. No. 13).--_Murie, J._, “On the occurrence of
_Œstrus tarandi_ in a Reindeer in the Zoological Society’s Gardens,”
‘P. Z. S.,’ 1866, with woodcuts.--_Idem_, “On a Leech (Trocheta) found
in the Viscera of a Molluscan Deer (_Cervus moluccensis_, _Müller_),”
_ibid._, 1865.--_Numan_, “Over den Veelkop-blaasworm der Hersenen” (this
beautifully illustrated memoir, in the ‘Trans. of the Dutch Soc. of
Sciences,’ supplies an elaborate bibliography of continental writings
on _Cœnurus cerebralis_--T. S. C.), ‘Œrste Kl. Verh.,’ 3e Reeks, 2e
Deel, p. 225 _et seq._--_Oliver_ (see Bibl. No. 13).--_Padley, G._, ‘On
Entozoa from a Sheep;’ see Sandie.--_Parsons_, “On Diarrhœa in Lambs
(with bronchial worms),” ‘Veterinarian,’ 1855, p. 685.--_Patellani_,
“Sturdy in Cattle,” from ‘München Jahresbericht,’ in ‘Veterinarian,’
vol. xxx, p. 81, 1857.--_Pellizzari_ (see Bibl. No. 13).--_Perroncito_
(see Bibl. No. 13).--_Pourquier_ (see Bibl. No. 13).--_Ralph, T. S._,
“On the Parasitic Nature of Pleuro-pneumonia,” &c., two papers in
‘Austr. Med. Journ.,’ 1865.--_Ranke_, “Pulmonary Entozoic Disease of
Sheep,” ‘Path. Soc. Trans.,’ 1858; see also ‘Veterinarian,’ vol. xxx, p.
708, 1857.--_Raynaud_, “A Word on the Cachexia, or Rot in Ruminants,”
trans. from the ‘Journ. des Vét.,’ by W. Ernes, in ‘Veterinarian,’
vol. xxxiii, p. 488, 1859.--_Read, R._, “Destruction of Strongylus and
Filaria in the Bronchial Passages of Calves, through nasal inhalation
of ether, chloroform, oil of turpentine, or rectified oil of amber,”
‘Veterinarian,’ vol. xxi, p. 604, 1848.--_Reck_ (see De Reck).--_Reed,
R._, “Congenital Hydatids in a Lamb,” ‘Veterinarian,’ vol. viii, p.
551, 1835.--_Rhind_, “Description of a species of Worm (Pentastoma)
found in the Frontal Sinus of a Sheep,” ‘Farrier and Naturalist,’ vol.
iii, p. 277, 1830, and ‘Lancet,’ 1829.--_Robertson_, “Remarks on Tænia
in Lambs,” ‘Rep. of Scottish Med. Vet. Soc.,’ in ‘Veterinarian,’ 1875,
p. 80.--_Rochard_ (see Bibl. No. 13).--_Rose, C. B._, “On Cœnurus and
Acephalocysts,” ‘Lond. Med. Gaz.,’ vol. xxiv, p. 525, 1844.--_Idem_,
“On the Anat. and Physiol. of the _Cysticercus tenuicollis_,” ‘Roy.
Med.-Chir. Soc. Trans.,’ and ‘Lancet,’ 1848.--_Idem_, “On the Vesicular
Entozoa, and particularly Hydatids,” ‘Lond. Med. Gaz.,’ vol. xiii, p.
204, 1833-34.--_Sandie_ (with _Padley_), “On Entozoa in the Lungs of
a Sheep,” ‘Ann. Nat. Hist.,’ 1849.--_Schwarzmeier_, “Die Trepanation
des Rindes bei Cœnurus,” ‘Wochenschr. f. Thierheilk.,’ 1875, s.
295.--_Shenton_, “Worms from the Stomach of a Cow,” ‘Veterinarian,’
1844, p. 487.--_Siedamagrotzky_, “Hydatids in the Liver of a Cow,”
‘Bericht üb. das Veterinawesen im Kön. Sachsen,’ 1875, s. 29.--_Simonds,
J. B._, “Death of Sheep from Worms in the Stomach (abomasum), being
remarks on Mr. Haywood’s case,” ‘Veterinarian,’ vol. xxxiv, p. 525,
1861.--_Idem_, ‘The Rot in Sheep, its nature, cause, treatment,
and prevention,’ London, 1862.--_Idem_, “On Filariæ in the Bronchi
of Calves,” ‘Trans. Vet. Med. Assoc.,’ 1843, p. 517.--_Idem_, “On
Strongylus in the Bladder and Intestines,” _ibid._, 1843.--_Idem_,
“On Hydatids of the Liver of a Sheep (Mr Scruby’s case),” _ibid._, p.
331.--_Idem_, “On Disease of the Mesenteric Artery from Strongyli within
the Vessel,” ‘Path. Soc. Trans.,’ 1854.--_Idem_, “Lecture on the Nature
and Causes of the Disease known as Rot in Sheep,” vol. xxxiv, p. 274,
1861.--_Spence, G. W._, “On Œstrus of the Ox,” ‘Edin. Med. Journ.,’
1858, and ‘Edin. Vet. Rev.,’ vol. i, p. 400.--_St Cyr_ (see Bibl. No.
13).--_Stoddart, J._, “Case of Hydatids in the Liver (of a Cow),”
‘Veterinarian,’ vol. xi, p. 637, 1838.--_Sutton_ (Lecture), ‘Gardiner’s
Chronicle,’ June 29, 1872.--_Sylvester, F. R._, “Cases of Parasites
infesting the Brains and Intestines of Lambs,” ‘Vet. Rec.,’ vol. ii, p.
40, 1846.--_Thudichum_ (see Bibl. No. 13).--_Idem_, “Echinococci from
the Sheep’s Lungs,” ‘Rep. Med. Soc. Lond.,’ in ‘Assoc. Med. Journ.,’
1856, p. 195.--_Tommasi_ (see Bibl. No. 13).--_Van Beneden_, “On the
Development of Cœnurus,” from ‘Comp. Rend.,’ in ‘Ann. Nat. Hist.,’ vol.
xiv, 1854.--_Watson, K. W._, “Experiment for the Cure of the _gidd_
(Cœnurus) in a Sheep,” ‘Lond. Med. Repos.,’ 1815.--_Willemoes-Suhm_, in
‘Sieb. and Köll. Zeitschr.,’ Bd. xxv, s. 176.--_Wilson, E._, “On the
Anatomy of _Trichocephalus affinis_,” ‘Vet. Rec.,’ 1846.--_Wymann_,
“Note on Filaria in the Bronchi of a Sheep,” see Anon. on “Entozoa and
Parasites,” in ‘Amer. Journ. Sci.,’ vol. xxxix, p. 183, 1840.--_Youatt_,
“On Hydatids in the Sheep (symptoms, prevention, treatment, &c.),”
‘Veterinarian,’ vol. ii, p. 519, 1834.--_Idem_, “On the peculiar
Bronchitis in young Cattle, accompanied by Worms in the Bronchial
Passages,” part of lecture, in ‘Lancet,’ 1832.--_Idem_, “Hydatids in
the Brain of a St Domingo Goat,” ‘Veterinarian,’ vol. ix, p. 443,
1836.--_Idem_, “Bronchitis from Worms (in Cattle),” _ibid._, vol. vi,
p. 177, 1833.--_Idem_, “Hydatids in the Brain (in Cattle),” _ibid._,
vol. vii.--_Yvart_, “Brain Hydatids,” _ibid._, 1828, p. 19.--_Zahn_,
“Lungenwürmer beim Reh,” ‘Œsterr. Vierteljahrschr. f. w. Vet.,’ 1875,
s. 125.--_Zurn_ (see Bibl. No. 13).--For further references to the
literature of Hydatids in Animals, see Bibliography No. 20, _o_, in the
first half of this work.


PART IX (SOLIDUNGULA).

It will naturally be expected that I should give a full account of
the parasites of the solipedal, solidungulate, or equine mammals. As
regards the horse I regret that I cannot meet this expectation in so
complete a manner as the subject deserves; nevertheless, with the aid of
an extended bibliography the summary here offered will be found to be
tolerably exhaustive. At all events I think I may say that no similar
record has hitherto been attempted.

The liver fluke (_Fasciola hepatica_), though not very frequent in
the horse, is not uncommon in the ass. In dissecting-room subjects
at the Royal Veterinary College it is often encountered. In France
it was originally found in the horse by Daubenton. As I learn from
Sonsino, Dr. Abbate Bey recently recorded a similar find at Cairo. In
solipeds generally the liver fluke appears to be almost harmless, for,
notwithstanding the frightful ravages produced by rot amongst a variety
of animals besides sheep, we have no evidence of the destruction of
horses from this cause. In the German outbreak of 1663-65 multitudes of
cattle and deer perished, and in the French outbreak of 1829-30 five
thousand horned beasts succumbed in the arrondissement of Montmédy
alone. In neither of these epizoötics were the solipeds affected. More
importance attaches itself to the study of the amphistomatoid flukes.
These parasites, though in a scientific sense only recently discovered
in equine bearers, have been long known to the natives of India. They
appear to be capable of producing serious intestinal irritation. I
have described two forms (_Amphistoma Collinsii_ and _A. Coll._, var.
_Stanleyi_), which infest the colon. The specimens sent to Prof. Simonds
from India by Mr Stanley, V.S., were much larger than those sent to me
from Simla by Mr Collins, V.S., some ten years later (1875). As in all
other amphistomes obtained from the intestines of elephants and cattle,
the worms, when fresh, were of a bright brick-red color. By the natives
of India these parasites are called _Masuri_; but no description of
the worms had been published prior to the account which I gave of the
contributions forwarded by Major-General Hawkes, Mr Collins, and Mr
Stanley.

I shall have occasion to speak of the elephant’s _Masuri_ further
on; but in the meantime I must remark that the generally received
notion as to the parasitic cause of the earth-eating propensities of
various animals seems to have some foundation in fact. Not alone from
Major-General Hawkes in Madras, from Mr Folkard in Ceylon, and from
various other trustworthy sources, have I been informed of this habit on
the part of Indian horses, but Dr Rowe told me that Australian horses,
and even sheep, infested with stomach-worms, are in the constant habit
of consuming large quantities of sand. From all the facts that have come
before me, I am inclined to think that gastric or intestinal irritation,
however brought about, may induce the habit in question, parasites being
only one of the many sources of irritation giving rise to symptoms
of colic in solipeds and pachyderms alike. At all events the African
elephants at the London Zoological Society’s Menagerie, as repeatedly
witnessed by myself, are in the habit of swallowing large quantities of
soft mud during the summer months, but no traces of _masuri_ have as yet
been detected in their fæces.

When by letter I informed Major-General Hawkes of an interesting find
by Mr Collins of _about a thousand_ Amphistomes in the colon of a horse
that had died at Simla, the announcement called forth a reply which
is sufficiently instructive to be quoted. Writing from Secunderabad
in July, 1875, he says, respecting this “find:”--“Your statement has
incidentally thrown light upon a subject which has puzzled many of
us in this country. It occasionally happens that a horse, on being
opened after death, is found to have accumulated in his intestines
large quantities of sand and gravel. In a recent case this accumulation
amounted to 14-1/2 lbs. Until recently it was always held that this
gravel or sand could only be introduced with the animal’s food. All
grain in this country is trodden out by bullocks on an earthen floor,
and the grain undoubtedly contains a proportion of sand and gravel
derived from this source. Although this _ought to be_ carefully washed
out before it is given to the horse, still, owing to the carelessness
of the native horse-keepers, this cleaning is, I expect, often omitted.
In the daily ‘feed’ of eight or ten pounds of grain given to each horse
the utmost quantity of sand or gravel that could be found admixed
therewith would not probably exceed two or three ounces; consequently
it would take from 77 to 116 days to accumulate so large a quantity
as 14-1/2 lbs. Now, the advocates of the theory of the gradual
accumulation of sand in this way have never been able to explain why
the grain, grass, hay, and other ingesta should pass in the ordinary
way through the intestines, whilst this sand or gravel remains behind.
One can understand the possibility of such substances as wool, hair, or
similar matters concreting in the alimentary canal, though I believe
they are usually found in the stomach, and not in the intestines; but
how a most incohesive substance like sand can possibly accumulate
in the gradual way required by their theory I have never heard even
plausibly explained. On the other hand, the fact that horses are often
excessively addicted to eating earth is well known; and if my memory
serves me correctly, it was found necessary, about twenty years ago, to
remove the mud-walls of the pickets surrounding some of the horses of
a mounted corps in this presidency in consequence of this habit. Now,
given the fact that the amphistoma has been found in the horse (as your
specimens prove), may we not fairly suppose it possible that the animal
resorts to the same mode of ridding himself of this parasite as does the
elephant? and also, would it not in a much more natural manner account
for the large quantity of gravel or sand found in the intestines than
does the theory of gradual accumulation? Reasoning from analogy, as
in the case of the elephant, this eating of earth in the horse would
be an instinctive effort on the part of the “host” to rid himself of
the parasite. This self-taken remedy is doubtless in many cases quite
effectual, _though unnoticed_. The fatal cases are probably those in
which the horse has either overdone the remedy or where the system was
too debilitated to carry off a quantity of sand or gravel that would
otherwise have safely passed through the intestines of a horse in more
robust health. The actual fact must, of course, be verified by careful
investigation.”

[Illustration: FIG. 62.--_Gastrodiscus Sonsinonis._ _a_, Mouth; _b_,
caudal sucker and posterior mesial cleft; _c_, left lip of the gastric
disk; _d_, anterior mesial cleft; _e_, e. gastric suckerlets; _f_,
reproductive papilla. Enlarged. Original.]

Closely allied to the Masuri is an amphistome which I originally named
_Gastrodiscus Sonsinoii_, but which should be altered as opposite
(Fig. 62). It exceeds 1/2″ in length and 1/3″ in breadth (16 mm. long
by 10 broad). Its discovery by Dr Sonsino was one of the results of
his examination of sixteen carcases of solipeds that died during the
Egyptian plague of 1876. Specimens having been forwarded to Panceri,
Von Siebold, Leuckart, and myself, most of us at once agreed that the
worm was new to science. Pointing to the genera, _Notocotylus_ and
_Aspidocotylus_, I explained its close affinity to the latter more
particularly. Whilst _Notocotylus_ has fifty supplementary suckers on
its back, _Aspidocotylus_ has nearly two hundred small ventral suckers
seated on a convex disk. In _Gastrodiscus_ a still larger number of
suckerlets are placed in the deep concavity of a large gastric disk
formed by the outstretched and inrolled margins of the body of the
parasite. Zoologically speaking, the odd thing about this singular
worm lies in the circumstance that its nearest fluke-relation, so
to speak (_Aspidocotylus mutablis_), dwells in a spiny-finned fish
(Cataphractus); and this fish itself forms an aberrant genus of the
family to which it belongs (Triglidæ). From what has been said it
will be seen that our _Gastrodiscus_ must not be confounded with
_Cotylegaster cochleariform_ (or with its synonym _Aspidogaster
cochleariformis_), to which parasite Von Siebold was, I believe,
induced to refer it. Like most of the true amphistomes, the worm in
question infests the intestines. Although discovered by Sonsino at
Zagazig in plague-affected corpses, there is no reason to suppose that
this helminth was in any way etiologically connected with the Egyptian
epizoöty.

The tapeworms of the horse are of great interest practically. Excluding
Sander’s _Tænia zebræ_, which was doubtless _T. plicata_, at least
five species have been described, but they may probably be all reduced
to two distinct forms and their varieties. Whilst _Tænia plicata_
acquires a length of three feet, the strobile of _T. perfoliata_ never
exceeds five inches. The lobes at the base of the head in the latter
are distinctive. The former is usually confined to the small intestine,
but the perfoliate worm often occupies the cæcum and colon in great
numbers. As regards _T. mamillana_, I may say that neither Gurlt’s
descriptions nor his figures are convincing. The worm is, I believe,
identical with _T. perfoliata_. In like manner, after going into the
matter with some care, I am accustomed to speak of Mégnin’s _T. inerme_
as _T. perfoliata_, var. _Mégnini_, and of Baillet’s _T. innomé_ as
_T. perfoliata_, var. _Bailletii_. I have examined great numbers of
equine tapeworms, but whether my determinations on this point are
correct or not, the case recorded by Mégnin is of remarkable interest.
Clinically, indeed, it is not entirely unique, since a somewhat similar
case has been recorded by Mr Poulton. In Mégnin’s equine patient the
autopsy revealed the presence of 200 bots, 153 lumbricoids, upwards of
400 oxyurides, and several thousand palisade worms, besides numerous
tapeworms. In Mr Poulton’s patient large quantities of tapeworms were
found in the duodenum (and in large sacs of the walls of other sections
of the small intestine), and also myriads of the little four-spined
strongyle, in addition to about a score of palisade worms. Both Mégnin’s
and Poulton’s patients died suddenly; but the great interest attaching
to Mégnin’s case arises from the boldness of manner in which the
French _savant_ interprets the phenomena of the intestinal sacculation
in relation to the development of the tapeworms. M. Mégnin assumes
that the sacs are due to the formation of polycephalous or cœnuroid
scolices. Without contradicting Mégnin’s ingenious interpretation of
the phenomena in question, I may say that the difficulty I have in
accepting his view arises from the circumstance of the rarity of the
occurrence of these sacs. In Poulton’s case of _Tænia perfoliata_, the
sacs were present, and they were productive of similar results; but
in the scores of other recorded cases of sudden death from the same
species of tapeworm (as published by Mr Rees Lloyd, and myself), the
presence of such sac-formations is not once mentioned. To be sure,
their presence may have been overlooked, but this is scarcely likely,
seeing the great care taken by Mr Lloyd in conducting the autopsies.
I cannot dwell upon the subject at greater length. The presence of so
many sexually-immature strobiles, combined with the existence of the
intestinal wall sacs, certainly does seem to point to the existence of
cœnuroid bladder-worms, but until the existence of the polycephalous
scolex be actually demonstrated one must be cautious in concluding “that
the horse nourishes at the same time the strobila and scolex of the
unarmed tapeworm.” Practically, we now know for certain that not only
are tapeworms capable of producing a fatal issue in isolated cases,
such as those recorded by Mégnin and Poulton, but that they may also be
productive of disastrous epizoöty, as proved by Mr Lloyd in the case of
Welsh mountain ponies.

In this connection I may perhaps be pardoned for saying that this
discovery in 1875 was one of the practical results directly issuing
from the publication of my ‘Manual’ in 1874. The attention of the
veterinary profession having been called to the subject of parasitic
epizoöty, Mr Lloyd was the first to make search for helminths amongst
some few of the carcases of the hundred and more equine animals that
perished in South Wales. Two totally distinct epizoötics prevailed. In
the Beacons district tapeworms alone were the cause of death, whilst
in the Deangunid district scores of animals perished from strongyles.
In another district a hundred animals perished from tapeworms. These
parasites I identified as examples of _Strongylus tetracanthus_ and
_Tænia perfoliata_. Taking all the helminthological facts together
we have made a great advance both in hippopathology and equine
epidemiology; and, as I observed at the time, the scepticism which not
unnaturally still exists (in reference to entozoa as a frequent cause of
death amongst animals, both wild and domesticated) will sooner or later
be dispersed by that wider attention to the subject which our labors
have invoked.

In relation to equine disease the facts brought forward are too
important to be dismissed in a single paragraph. As two distinct kinds
of parasitic epizoöty were discovered, the circumstances connected with
their separate detection must be noticed at greater length. Further
on, I shall again deal with the helminthiasis due to strongyles. It
was on the 17th of April, 1874, that I received from Mr Lloyd, of
Dowlais, Glamorganshire, a communication calling my attention to a
fatal epizoötic affecting ponies. He supposed the outbreak to be due
to parasites. On the following day I also received a parcel containing
portions of the lower intestines, which had been removed from one of the
diseased animals. The victim in question, a pony mare, had died on or
about the 12th of April, at Llangunider, Breconshire. Mr Lloyd states
in his letter that he “presumes” that the pony’s death was caused “by
the presence of small worms,” examples of which he now forwarded for
the purposes of identification and investigation. He also sent some
equine tapeworms. Mr Lloyd had already inferred that his small worms
were “strongyles;” and in regard to the tapeworms he says:--“This
species of parasite has caused, or is supposed to have caused, the
death of at least one hundred mountain ponies.” The investigation
being immediately proceeded with, I may so far anticipate my record of
the results obtained as to state at once that the facts observed by
me confirmed Mr Lloyd’s suspicions--proving, beyond a doubt, that the
pony above mentioned had succumbed to injuries inflicted by myriads of
minute strongyles. Not only did I find the fæcal matter of the colon
loaded with mature strongyles, but the walls of the intestine were also
occupied with encysted and immature forms of the same nematode species.
To such an extent had infection taken place, that I was enabled to
count no less than thirty-nine strongyles within the space of the one
fourth of a square inch. All parts of the sections of the colon under
examination were almost equally invaded; so that, taking the average,
I am clearly within the mark in saying that every square inch of the
gut yielded at least one hundred parasites. The walls of the entire
colon must therefore have been occupied by tens of thousands of these
creatures, to say nothing of the scarcely less numerous examples lying
free or lodged within the fæcal contents of the bowel.

In a second and more extended communication, sent in reply to inquiries
as to the cestodes, Mr Lloyd (whose letter I have abridged) writes:--“I
regret that I cannot give you very full particulars respecting the
tapeworms. During the last twelve months mountain ponies grazing on
the lower districts of Breconshire, which comprise some of the highest
mountains in South Wales, have been dying in great numbers, from what
the farmers indefinitely term inflammation. From what I have seen and
heard, it appears that there are three causes of death, the tapeworm,
the small worms (which I presumed were a kind of strongyle), and
catarrhal disorders, such as have been common among horses of late.
By far the greater number of deaths (from what I can glean) have been
caused by the parasites. In the Ystradfellte or Penderin districts there
has been no investigation, although the disease has reigned there for a
longer period, about eighteen months, with (from what I have heard) a
larger number of deaths than elsewhere; so I shall let these remain for
the present, as I have not had an opportunity to see or hear anything
authentic about them. In the Talybont district the cause appears to
be the small worms (like those I sent). The owner of the animals said
that a month ago, when he went to look after his ponies, they were
appearing quite well, and looked as well as he could expect them at
this season, but he was astonished to find some of them a fortnight ago
looking very lean and wasting, and he thought that the weather was the
cause of it, yet resolved to see them oftener; the next time he saw
them one was dead, and knowing of the loss in the neighbourhood, and
fearing he would be a sufferer, he sought aid, applying to me. When I
arrived two days following two more were dead, and they presented an
emaciated appearance. The post-mortem examination revealed a healthy
condition of the whole of the intestines, save slight thickening of some
parts of the colon and rectum, which contained, enclosed in the mucous
membrane, in cysts or minute sacs, worms coiled upon themselves. Each
cyst, containing one worm, was best seen by transmitted light. The colon
was nearly full of fæcal matter, which contained thousands of parasites
scarcely visible. The largest were very few in number, not exceeding
an inch in length and barely one sixteenth in diameter at the middle
portion. They somewhat tapered at both ends. The cæcum was half full
of fluid fæces, containing no visible worms; the rectum, with fæces of
natural consistence, the examination of which revealed only two or three
evident worms; so that the examination of fæces of living animals giving
results like this would not assist the diagnosis, unless suspected.
Small intestines--these latter contained about a dozen bots, which
were nearly free, but had pierced to the muscular coat. I should think
they had participated in the disease. The right lung had been slightly
congested; nothing else abnormal to be seen. Possibly congestion of
lungs would arise from the distress when pained with worms, for the pony
was found on its back with its head in a thicket--it had not appeared to
have struggled--with its teeth firmly closed.

“Respecting the animals affected with Tænia, it is remarkable that, as
a rule, they are in fair condition. The average time they appear to be
troubled with the worms is two months, and the symptoms observed have
been many. They are at first seen to be unable to keep up with the
other ponies, extending the head and turning the upper lip up, rubbing
the quarters, staring coat, suddenly appearing distracted, seizing
turf in mouthfuls when being griped or pained, others running away as
fast as they can go, or rolling and kicking on the ground for five or
ten minutes, then walking away as if nothing had happened, if coming
down a slope quickly almost sure to fall headlong, easier caught, not
unfrequently coughing, groaning noise, appetite good, and, what is
peculiar in some of them, lameness of one of the hind limbs, mostly the
near hind leg, with slight knuckling over at fetlock.

“_Post-mortem appearance._--Abdominal viscera normal, save rectum,
which is in some places slightly congested; colon nearly full of fæces,
no worms; cæcum, in which worms are alone found, is nearly full of
fæcal matter of thicker consistence than usual, and nearly half made up
of worms; stomach half full of partly digested food; heart and lungs
healthy; Schneiderian membrane injected; mucous membrane of trachea and
part of larger bronchiæ of a more or less livid colour (which may be
owing to asphyxia); corner of tongue bitten off; mouth very close.

“Several animals were found at times lying dead together.

“Of the _Tænia_ as many as three or four ponies, which some hours
previous had been seen grazing unaffected, were found dead on the same
spot; and this to my own knowledge, one farmer having lost ten.

“Of the small worms I have been told by a farmer that in his district
one of his neighbours had lost twelve ponies.”

As I had partly misunderstood my informant’s original statement, Mr
Lloyd, in a third communication, repeated the evidence, emphatically
reminding me that “the ponies affected with tapeworms are in a district
six or seven miles distant from those affected with strongyles. Those
troubled with tapeworms are in good condition, as a rule, up to death;
they are noticed to be troubled generally for two months previous to
death, and may be seen at one hour grazing and apparently well, and dead
or dying the next hour. As many as four have been found dead at the same
spot. In this (the Beacons) district the tapeworms alone have been found
and not a single strongyle. In the Deangunid district strongyles only
have been found, such as I sent you. The ponies have been noticed ailing
for three or four weeks, becoming rapidly emaciated and dying from
exhaustion. In tapeworm-affected animals the cæcum is nearly half full
of these parasites. The animals thus affected are on the red sandstone
formation, whilst those affected with strongyles occur on the limestone
formation--the latter affording the drier situation.”

Being on the teaching staff of the Royal Veterinary College I was
particularly glad to have the authority of an experienced veterinary
practitioner to testify to the injuriousness of _Tænia perfoliata_ in
the horse. Over and over again I had pointed out to the members of my
class the desirability of examining the fæces of solipeds where obscure
symptoms of intestinal irritation existed. Not only so; at the request
of friends I wrote out prescriptions suitable for equine patients
suffering from tapeworm. I felt the more indebted to Mr Lloyd, inasmuch
as his practical views served to strengthen the propositions I had
advanced in connection with internal parasites as a frequent cause
of epizoötics. My views were criticised at the time with a vigour and
warmth well worthy of those who are afraid of advancing epidemiological
science too rapidly; but it seems that so far from my having overstepped
the bounds of moderation in this matter I had, in reality, been too
cautious. Certainly it can now no longer be said that “the symptoms
created by tapeworms in the horse are of little or no consequence.”
Here, therefore, I repeat, we have made a clear and rapid advance in
our knowledge of helminthic disease; and from the impulse thus given to
hippopathology it is only reasonable to look for still further advances
in veterinary medicine. By-and-by, the scepticism which not unnaturally
exists in reference to entozoa as a frequent cause of death amongst
animals, will be dispersed by even yet clearer enunciations regarding
the important part these parasites play in the destruction of our most
valuable creatures.

Apart from the question incidentally raised by Mégnin as to their origin
and mode of development, the presence of larval cestodes in horses
cannot be passed over. The common hydatid (_Echinococcus veterinorum_),
though not of frequent occurrence, is occasionally productive of fatal
consequences. Very interesting cases are recorded by Messrs Henderson
and Kirkman, aided by the valuable comments of Professor Varnell. Mr
Hutchinson observed an hydatid in a horse’s eye, and Mr Vincent noticed
lameness, as resulting from hydatids. But one of the most interesting
cases of hydatids in solipeds is that described by Professor Huxley,
from a zebra that died at the Zoological Gardens in 1852. As stated
in Huxley’s elaborate memoir (freely quoted in the first part of this
work), the liver was found to be “one mass of cysts, varying in size
from a child’s head downwards.” The zebra’s death was purely accidental,
as it broke its neck while at play in the paddock. The long bladder-worm
of the horse (_Cysticercus fistularia_) is entirely unknown to me, and,
as before suggested, may be a mere variety of the _C. tenuicollis_ of
ruminants. An authentic instance of the occurrence of the gid hydatid
(_Cœnurus cerebralis_) in the horse is recorded by Gurlt. Lastly,
in relation to the question of food, it is worthy of remark that
whilst beef, veal, pork, and even mutton, are apt to be measled, the
muscle-flesh of horses is not liable to be infested by Cysticerci. This
is a fact in favor of hippophagy.

The nematodes of solipeds are very numerous, and first in importance
must be placed the palisade worm (_Strongylus armatus_). This worm was
known to Ruysch (1721). The old naturalists recognised two varieties
(_major_ and _minor_). These we now know to be merely the final stages
of growth of one and the same entozoon; and in both stages the worm
inflicts severe injury upon the bearer, chiefly, however, whilst
wandering through the tissues. The palisade worm has acquired notoriety
principally on account of its causing verminous aneurism, nevertheless,
this pathological change is not, in itself, the most disastrous evil
produced by the worm. In the adult state the female reaches a length
of two inches, whilst the male rarely exceeds an inch and a half. The
posterior ray of the caudal membrane or hood of the male is three-cleft.
In both sexes the head is armed with numerous, closely-set, upright
denticles, presenting the appearance of the teeth of a circular saw
or trephine. The eggs are elliptical and somewhat constricted at the
centre, their contents forming embryos after expulsion from both
parent-worm and host. The larvæ are rhabditiform, changing their skin,
in moist earth, in about three weeks, at which time they part with
their long tails. According to Leuckart, they pass into the body of an
intermediate bearer before entering the stomach of the definitive or
equine host. From the alimentary canal they pass to the blood-vessels,
causing aneurism, and thence they seek to regain the intestinal canal,
where they arrive at sexual maturity. It is during their migratory
efforts that they give rise to dangerous symptoms in the bearer, not
unfrequently causing the death of young animals, especially yearlings.
In the adult state the worm is also dangerous to the bearer, as it
produces severe wounds by anchoring to the mucous membrane of the gut.

The proofs we possess as to the frequency of abdominal, especially
mesenteric, aneurism from this source are overwhelming. Prof.
Brüchmüller estimated the percentage of aneurismal horses, six years old
and upwards, at 91 per cent., and it is a matter of common observation
in veterinary dissecting rooms that verminous aneurism is rarely or
never absent in the ass. Professors Dick, Simonds, Pritchard, Williams,
and many other English and Scotch veterinarians of eminence, have all
borne testimony of this kind, and, for myself, I may say that one of the
earliest pathological appearances with which I became familiar, some
thirty years back, was that presented by mesenteric arterial disease of
the ass. In relation to fatal colics in the horse the study of verminous
aneurism is of the highest moment. On this subject Prof. Friedberger
has published some valuable lectures, in which, amongst other points,
he incidentally remarks upon the comparative freedom of military horses
from aneurism as compared with ordinary laboring horses. This arises
partly from the fact that the latter are not cared for to the same
extent, dietetically and otherwise; and, moreover, cavalry horses are,
as a rule, younger than ordinary working animals. Whilst Friedberger,
in his suggestive brochure, does ample justice to the writings of
his colleague, Dr Bollinger, it may be said, in like manner, that he
does not fail to recognise his great indebtedness to the researches
of Leuckart. So practically important, however, do I deem Bollinger’s
summary of the whole subject in relation to the hippopathological
aspects of parasitism, that I feel it desirable to record his
conclusions at full length. No professional man having any pretensions
to a knowledge of the veterinary art--or, for that matter, to parasitism
in relation to sanitation--should remain uninformed on this subject. Dr
Bollinger’s results are thus stated:

1. The worm aneurism of the visceral arteries of the horse, existing in
90 to 94 per cent. of adult horses, has a general correspondence with
the _aneurisma verum mixtum_ of man. It is, however, distinguishable
from the same by its seat, cause, character of its walls, contents, and
mode of termination. The worm-aneurism arises from a parasitism of the
palisade worm (_Strongylus armatus_), owing to an inflammatory affection
of the arterial walls which it causes, and which one may describe as a
recurrent traumatic endo-arteritis. This holds good for all the visceral
arteries, with the exception of the abdominal aorta, in which an
aneurism may arise from local increase of pressure.

2. The formation and further development of the aneurism is also
favored by the narrowing of the arterial calibre, which is caused by
the inflammatory swelling of its walls, and also by the contemporaneous
formation of a thrombus (clot), this latter still further supporting and
exciting the inflammation of the inner coat.

3. Whilst the causes above mentioned (and of these more particularly the
continued presence of the palisade worms and the plugging of the smaller
arteries by thrombi) favor the growth of the worm-aneurism, the small
size of the same, notwithstanding the years it has existed, is explained
by the considerable hypertrophy of the muscular layer, by the tough
fibrous capsule formed in many cases by the connective tissue of the
mesentery, and by the adhesion of the intestines to the perpendicular
and free-lying anterior mesenteric artery; in particular this last-named
circumstance does not allow of any very considerable shortening of
the mesenteric artery, which would necessarily be accompanied by
considerable dilatation of the arterial tube.

4. The favorite seat of the worm-aneurism is the trunk of the anterior
mesenteric artery, directly at its origin from the abdominal aorta. Most
frequently that part of the arterial trunk is dilated from which the
arteria ilea, cæcales, and colica inferior (_arteria ileo-cæco-colica_)
arise, less frequently the arteria colica superior at its origin, and
the arteries of the cæcum and colon in their course in the meso-cæcum
and meso-colon. The verminous aneurism also occurs in the cœliac artery
(Bauchschlagader), in the posterior mesenteric artery (Gekrös-arterie),
in the renal artery, and in the abdominal aorta. A horse is not
unfrequently afflicted with several aneurisms of this kind at one and
the same time. Thus in one case (described by Bollinger) there were six
of these aneurisms affecting the abdominal aorta and its branches in the
same horse. The verminous aneurism may occur from the sixth month of
life onwards, and with increasing age; the number of horses free from
such aneurisms becomes continually smaller.

5. The size of the aneurism varies between that of a pea and that of a
man’s head. The dilatation is, as a rule, equal on all sides, the form
being usually thumb-shaped or bottle-shaped, passing into that of a cone
or long oval figure. This general configuration is principally due to
the free and moveable situation of the anterior mesenteric artery.

6. In contrast to aneurisms in man, the walls of the worm-aneurism of
the horse are almost without exception indurated. In addition to the
mesenteric connective tissue, all the arterial coats, and especially the
_tunica media_, generally take part in this induration. The hypertrophy
of the media, which stands unique in respect of what is known of
arterial disease, forms a compensatory action of the arterial wall,
analogous to the muscular hypertrophy of the heart in valvular disease.
This change in the media points to the fact that in the development of
aneurism in man the early disturbance of the nutritive process in the
_tunica media_ is not a less essential factor than the degeneration of
the _tunica intima_.

The changes in the _intima_ are the least constant. They present all
stages of progressive and retrogressive metamorphosis, from simple
induration to ulceration and calcification. In the walls of the
verminous aneurism one not unfrequently finds all the pathological
changes exhibited by _atheroma_ in man. Calcification is a common form
of the retrograde process, and, in very rare cases, may pass on to the
formation of true bone.

7. In addition to the palisade worms, one almost constantly finds a
parietal thrombus contained in the aneurism. It covers the inner wall
either partially or completely, being in the latter case perforated
for arterial offshoots. This clot may occlude the artery, and it is
not unfrequently continued into the arterial branches (peripherally)
or into the aorta (centrally). Amongst the various changes that the
clot undergoes, organisation of its outermost layer and softening are
the most frequent. The constant occurrence of this clot is due to the
presence of the worms, to the inflammation, ulcerative and regressive
affection of the intima, and to the dilatation of the arterial tube.

8. The palisade worms are seldom absent from aneurisms of the horse.
Their not being present is merely an accidental circumstance. On the
average, nine palisade worms go to a verminous aneurism, and eleven in
the horse. The highest number of worms found in one horse reached 121.
Not unfrequently, also, palisade worms, or their coverings in the form
of larval skins, are found in the aneurismal walls. The immigration and
emigration of the palisade worms out of the intestine into the aneurism,
and the reverse, take place probably, as a rule, within the arterial
circulation. The path of the worm does not appear to be always the same,
inasmuch as they can also wander through the peritoneal cavity. The
worms found in the aneurismal walls are probably mostly only strayed
specimens.

9. From a comparative pathologico-anatomical point of view, the
developmental history of the aneurysma verminosum proves that a
circumscribed endo-arteritis can determine the formation of an aneurism.

10. Like the worm-aneurism itself, atheroma of the abdominal arteries
arises from a circumscribed acute and subacute endo-arteritis. The
histological changes in the secondary atheroma of horses are perfectly
analogous to those of the spontaneous atheroma of man. Idiopathic
atheroma, as seen in man, does not occur any more in the horse than in
the other domestic animals. Atheroma in the horse is always secondary.
To be sure, one observes an idiopathic chronic endo-arteritis in
many abdominal arteries of the horse, which, however, never exhibits
indications of atheromatous degeneration.

11. In consequence of its position the worm-aneurism of horses is not
open to physical examination, and on that account cannot be diagnosed
by physical signs; moreover, it offers no characteristic symptoms.
Its termination by rupture is extremely rare, the aneurisms of the
abdominal aorta being more disposed to rupture than those of the
anterior mesenteric artery. Of eighteen cases of known perforation,
fifteen opened into the peritoneal cavity, and three into the bowel. The
dangerous symptoms of the worm-aneurism are exclusively due to embolism
and thrombosis of the affected artery, arising from the parietal clot.
The latter becomes especially dangerous through its increasing size and
the softening which often accompanies it. The absorption and shrinking
of this parietal clot, be it organised or not, is materially assisted by
the high pressure to which it is exposed.

12. The very marked symptoms of vascular obstruction--the
sero-hæmorrhagic intestinal infarct--in embolism and thrombosis of the
mesenteric arteries are easily explained by paralysis of the muscular
coat of the intestine, by the absence or paucity of valves in the portal
vein, by the readiness with which meteorismus (or flatus) arises,
especially in herbivora, and by the loose consistence of the intestinal
walls or villi.

13. The occlusion of the intestinal arteries, especially that arising
suddenly, always has for its result a partial or complete paralysis
of the portion of bowel which they supply. The palsy of the intestine
causes the forward movement of the intestinal contents to cease, a
stoppage of the fæces, a hindrance to the discharge of fæces and
gas, and also that exceedingly dangerous formation of gas (within
the intestinal tract) which in the herbivora is so abnormal, both
quantitatively and qualitatively.

14. In embolism and thrombosis of the mesenteric arteries the symptoms
during life are entirely identical with those observed in the so-called
colic of horses, as has been determined by numerous observations. The
partial paralysis of the bowel, which is brought on by the embolism and
thrombosis of the mesenteric arteries, forms in great part the chief
and leading feature of the series of symptoms known as the “colic” of
horses. The palsy of the bowel which arises in this way may explain also
the frequent ruptures of the digestive canal and the greater number
of its changes in position. The latter are specially favored by the
structure of the abdominal viscera in the horse.

15. The old changes which one finds in the peripheral branches of the
anterior mesenteric artery, in the form of expired and partly absorbed
embolic and thrombolic processes (pigmentation, arterial and venous
thrombi), particularly in connection with those arteries which are seats
of the aneurism, decisively prove that the large majority of colics
resulting in recovery, so far as they do not depend upon known injuries,
are caused by paralysis of the bowel from embolism and thrombosis. The
sudden occurrence, course, and result of these kinds of colics also
testify to their embolic origin.

16. The œdematous, inflammatory, and hæmorrhagic processes that one
often finds described as the cause of death in colic, almost exclusively
depend on thrombosis and embolism of the mesenteric arteries, the cases
forming about 40 to 50 per cent. of all fatal colics.

17. The rapid course in fatal colics, as well as the preponderating
symptoms of dyspnœa in cases of recovery, is finally due to the
abnormal development of gas in the alimentary canal. In addition to
the diminution of the respiratory surface by the lofty position of
the diaphragm, a direct gas-poisoning (carbonic acid and sulphuretted
hydrogen) probably contributes to the intensity of the symptoms and the
rapid course by diffusion of the abnormally developed gas out of the
intestinal canal into the blood.

18. The variety of the anatomical derangements caused by embolism and
thrombosis of the intestinal arteries is faithfully mirrored by the
variety of the clinical symptoms and the different degrees in the
intensity and course of the colic.

19. Amongst every 100 horses afflicted with internal disease, 40 are
ill with colic. Among any hundred deceased horses 40 have perished from
colic, and among 100 colic patients 87 recover and 13 die. The figures
prove that neither amongst the epizoötic nor sporadic diseases of horses
is there any other affection which occurs so frequently, or claims
anything like so many victims. Like the frequency of the worm-aneurism,
the amount of disease and mortality increases with advancing age. The
etiology of the colic of horses finds in the thrombosis and embolism of
the mesenteric arteries, with the consequent paralysis of the bowel, an
all-sufficient explanation, whilst the causes of colic hitherto accepted
were for the most part insufficient.

20. In a great number of cases the thrombus of the worm-aneurism is
continued past the mouth of the anterior mesenteric artery, into
the lumen of the aorta, and, as such, is the exclusive cause of the
embolisms of the pelvic and crural arteries which bring about the
intermittent hobblings (the author says “intermitterenden Hinken,” not
“Hahnentritten,” the usual equivalent term for stringhalt). Considering
the excessive frequency of the thrombus being continued into the
aorta, it becomes highly probable that a great part of the diseases
and lameness of the posterior extremities (“Hüft und Kreuzlähme,
unsichtbarer Spath, &c.,” which may be rendered “sciatic and hip or
spinal lameness, obscure spavin, &c.”) are due to occlusion of the
arteries.

21. Owing to the fibrous thickening of the connective tissue of the root
of the anterior mesenteric round the aneurism, and to the considerable
size of the latter, disturbances of the innervation of the intestine,
(as well as) hindrances to the passage of the chyle, and irregularities
in the portal circulation may be created, which may well lie at the root
of many chronic disturbances of digestion in horses.

22. Considering the great losses and heavy social disadvantages that are
occasioned by the colic of horses to the horse-breeder, to agriculture,
and to the general welfare, it is of the highest importance to discover
means which should prevent the introduction of the embryos with the
food, and, as a consequence, the migration of the palisade worms into
the mesenteric arteries of the horse.

I wish it to be distinctly understood that the above summary is
translated from Bollinger (_Die Kolik_; s. 257). Instructive cases have
been recorded both at home and abroad. Prof. Varnell has remarked that
“foals and yearlings suffer more from parasites in the paddocks than
they do on adjoining farms where only a few animals are bred.” This is
explained by the relatively greater amount of egg-dispersion proceeding
from the infected brood-mares. It is quite evident that the lives of
many valuable animals are annually sacrificed by the neglect of hygienic
arrangements. The palisade worm is chiefly destructive to young animals,
and as Mr. Percivall has well remarked, these parasites are “commonly
the cause of lingering and hidden disease, terminating in death,”
without any suspicion on the part of the practitioner as to the nature
of the malady. Instructive cases of this form of helminthiasis are given
by Messrs Littler, Wyer, Harris, Meyrick, Litt, Percivall, Tindal,
Walters, Brett, Aitken, Mead, Clancy, Baird, Mercer, Wright, Seaman,
Hepburn, and others.

[Illustration: FIG. 63.--Larvæ of _Strongylus tetracanthus_. _a_, from
the walls of the intestine (natural size); _b_, the same (enlarged);
_x_, an injury; _c_, younger specimen (_in sitû_); _d_, the same
(enlarged). Original.]

Second only in clinical importance is the little four-spined strongyle
(_S. tetracanthus_). The sexes, often seen united, are nearly of equal
size, the largest females reaching nearly 3/4″. They infest the cæcum
and colon, and have been found in all varieties of the horse, ass, and
mule. The worm occurs in immense numbers and is a true blood-sucker.
Its presence occasions severe colic and other violent symptoms, often
proving fatal to the bearer. As already announced, in connection with
my account of the tapeworms of the horse, this little worm may produce
a virulent epidemic (epizoöty). In the sexually-immature state the
worm occupies the walls of the large intestine, where it gives rise to
congestion, ecchymosis, inflammation, and the formation of pus deposits.
The species is readily recognised by its bright red color, by the four
conical spines surrounding the mouth, by the two neck-bristles, and by
the long three-lobed hood of the male, the posterior three-cleft ray
having a rudimentary or fourth branch attached to its outer edge. In
some specimens sent to me by Mr Whitney, I found this supplementary
process fully twice as long as Schneider has represented it.

From the earliest times this entozoon has been confounded with the
palisade worm. Rudolphi and several of his successors, and also in
recent times Ercolani and Colin, regarded this worm as the progeny of
_Strongylus armatus_. During my earlier examinations I likewise fell
into the error of describing the immature worm as representing a new
species. The parasites described by me as Trichonemes (_T. arcuata_)
were identical with those which Prof. Dick had previously described as
“worms at different stages of growth,” in his MS. sent to Dr Knox, 1836.
Parasites of this kind were described by Dr Knox as “Animals similar
to _Trichina_;” by Diesing as the “Nematoideum equi caballi;” by Mr.
Littler as “Extremely small ascarides,” in a letter to Mr Varnell; by Mr
Varnell himself as “Entozoa in various stages of growth;” and by Prof.
Williams as “Entozoa from the intestinal walls,” in a letter to myself,
dated March 13th, 1873. In reference, however, to Mr Varnell’s account
of Mr Littler’s specimens I may observe that the appearances which he at
first merely described as “blood spots,” he afterwards characterised as
dark points “containing young worms in various stages of growth.”

As regards the course of development of this worm we have yet much to
learn. Although the worm is a frequent cause of epizoöty in this country
it appears to be but little known on the Continent. Krabbe makes no
mention of the helminthiasis set up by the four-spined strongyle, but he
points out that the young occupy the mucous membrane, in which situation
they lie coiled so as to present to the naked eye the appearance of
little dark spots (_Husdyrenes Indvoldsorme_, 1872, p. 17, ‘Aftryk. of
Tidsskr. for Vet.’). However, Leuckart’s account of the appearances
presented in a case brought under his notice is instructive. He
writes:--“I have hitherto had only a single opportunity of examining
the strongyle capsules in the intestinal membrane of the horse. Their
presence is limited to the cæcum and colon, but they are so abundant in
this situation that their numbers may be estimated by many hundreds. It
was thus likewise in the case in question, the investigation of which by
myself was rendered possible through the friendliness of Prof. Haubner
of Dresden. The capsules were of oval form, and glimmered through the
mucous membrane as opaque spots, mostly from one to three millimètres
in size. In several of these capsules nothing was found beyond a greasy
mass of a brownish color, which might readily be taken for a tuberculous
substance; but the greater number of them contained a coiled worm,
from three to six millimètres long, their breadth being 0·15 to 0·26
mm. (which is 1/166″ to 1/99″). They exhibited a highly colored stout
intestine, and a thick-walled oral capsule of 0·022 mm. in depth and
0·025 mm. in breadth. On the dorsal side two three-cornered chitinous
lamellæ arise from the shallow floor of the small oral capsule. The
cuticle, notwithstanding its firm structure, was still destitute of
annulations. The tail (0·15 to 0·18 mm. in length) was strongly marked
off from the rest of the body, being of a slender cylindrical form with
a rounded-off extremity. The development of the sexual apparatus had not
yet commenced. Notwithstanding the great differences of size presented
by the body, the structure of all examples was exactly the same to the
minutest particular, without exception. Also the smallest specimens,
which scarcely measured one millimètre, found in capsules of 0·3 mm.
in diameter, were distinguishable only by the absence of the oral cup,
whose position was represented by a slender and thickened chitinous
cylinder, as obtains in the earliest parasitic juvenile condition of
_Dochmius trigonocephalus_. The transformation to the form presenting
an oral cup occurs through a moulting, which is accomplished already in
examples of 1·5 mm. in diameter. Later, also, the worms cast their skins
in their capsules, without, however, changing the oral cup. In regard
to the final purpose of this metamorphosis, my investigations have left
me entirely in the lurch; nevertheless, I do not entertain the smallest
doubt that the worms which I have here described are the larval forms of
_Strongylus tetracanthus_.”

[Illustration: FIG. 64.--Fæcal cysts or pellets containing the larvæ of
_Strongylus tetracanthus_. Specimen (_a_) being enlarged (_b_) to show
the protruding head and tail (_c_) of the worm. Original.]

From numerous examinations I have satisfied myself that the worms after
escaping the walls of the intestine--and they may often be observed in
the very act of passing--re-enter the lumen of the bowel to undergo
another change of skin prior to acquiring the adult state. This they
accomplish by rolling themselves within the fæcal matter of the horse’s
intestine. The best examples I have seen of this phenomenon occurred
in a case for the clinical particulars of which I am indebted to Mr
Cawthron. Most interesting was it to notice these immature worms, each
coiled within a sort of cocoon, which Mr Cawthron termed a cyst. All
the forty little cocoons more or less resembled pills, the bright red
color of their contained worms strongly contrasting with the dark color
of the cocoons. They consisted of compressed _débris_, which under the
microscope showed many common forms of vegetable hairs and parenchyma,
besides raphides and chlorophyll-granules. Internally, there was a
cavity corresponding with the shape of the worm. In one instance I
noticed that the worm had nearly completed its ecdysis, a portion of
the old skin still remaining attached to the tail.

As already remarked, the evidence respecting the frequency and
destructiveness of this little worm in England is now quite
overwhelming. In a series of papers contributed to the ‘Veterinarian’
(too long for full quotation here), I have endeavoured to do justice
to the “finds” and observations of those members of the veterinary
profession who were good enough to supply me with valuable notes and
communications. In particular must my indebtedness to Mr Rees Lloyd
be acknowledged, for, as previously observed, he it was who first
recognised the parasitic character of the Welsh epizoötic outbreaks. In
the Deangunid and Talybont districts these strongyles proved terribly
fatal to mountain ponies. It appears that the owners of the animals,
as soon as they perceived anything amiss, at once disposed of them by
sale, evidently anticipating fatal results sooner or later. The facts
connected with some of the isolated cases brought under Mr Lloyd’s
care are especially interesting, as showing the virulence of the
symptoms set up. Thus on the 9th of Feb., 1875, some time after I had
identified the species from specimens he had sent me, Mr Lloyd writes
as follows:--“The last case I had was one which had been sold in this
way, and which had suffered now and then from colicky pains for the
space of about two months. The animal had been drenched with febrifuges
and rubbed with stimulating liniments about the throat. However, I
was sent for one evening, about an hour before the patient’s death. I
soon diagnosed the case as parasitic, and at the same time considered
it to be a hopeless one. I remained with it the whole of the time, of
which about forty-five minutes of the most acute pain was borne by the
trembling beast, which was leaping, rolling, and tossing itself about
with astonishing rapidity. The bulging eyes, gnashing teeth, foaming
mouth, and sharp peculiar hoarseness, were pitiable to behold; when
suddenly all was silent, he quietly rose to his feet, and nipped the
grass as if nought had troubled him. I then trotted him quietly up a few
yards of rising ground in the corner of the field, when he immediately
got down to rise no more. The next day I examined him, and found myriads
of the four-spined strongyles, a large number being encysted.” Mr Rees
Lloyd’s account of this case is so graphic that I have reproduced it
without abridgment. Speaking of another patient, a mare, he says,
“she had voided thousands of these parasites, and was in a frightfully
emaciated condition, but beyond a craving appetite there was little else
to be noticed.” Notwithstanding the few diagnostic indications afforded,
Mr Lloyd, being led by the history of the case to suspect worms, at
once examined the fæces, when he discovered thousands of these minute
nematodes. Clinically, these facts ought not to be lost sight of. In
addition to Mr Lloyd’s cases I have received valuable particulars of
others at the hands of Prof. Williams, Messrs Cawthron, A. Clarke, T.
Gerrard, D. M. Storrar, and J. W. Whitney.

Practically, it is important to inform the persons most interested that
an active “drench” may be serviceable in dislodging the free intestinal
worms, but the administration of purgatives must not be persevered in.
As in the somewhat parallel case of Trichinosis in the human subject,
the fatality of the disorder depends not upon the free and mature worms,
but upon the migrating and sexually-immature forms. All attempts by
means of active drugs to poison the entozoa, when once they have gained
access to the tissues (whether actually capsuled or not), are worse
than useless. By all means let the animals have a dose of aloes in the
first instance, followed by warm bran mashes; but thereafter let every
care be taken to support the patient’s strength. Especially should the
exhibition of turpentine be avoided. Without doubt the cause of this,
as of other similar epidemics, is primarily referable to atmospheric
conditions which favor the multiplication of parasites. As the practical
man cannot alter these climatal changes, he must do his best to check
the disorder by removing the victims to new localities; or, if the
animals must remain in infected districts, by supplying them with
various kinds of artificially prepared fodder, supplemented by carefully
filtered water. In this way, I believe, epidemics may be arrested,
but they cannot be stamped out altogether, except by the adoption of
measures which would be alike impracticable and unwarrantable.

Passing to the consideration of other intestinal nematodes, the next in
importance is the large lumbricoid (_Ascaris megalocephala_) found in
all solipeds, including the zebra. Whilst the male worms rarely exceed
seven inches in length, the females sometimes reach seventeen inches.
Science is indebted to Schneider for setting at rest all doubt as to
the specific distinctness of this worm. The far larger number of caudal
papillæ at once distinguishes it from the lumbricoid of man and the
hog. The equine Ascaris may occur in any part of the alimentary canal,
but the small gut forms its proper head-quarters. The entire course of
development of this worm has not been traced; nevertheless, Heller found
human lumbricoids measuring less than the eighth of an inch. It is not
likely that any intermediate host is necessary for the growth of the
larvæ, prior to their access to the definitive host. I have reared the
larvæ in impure water and in moist horse-dung, up to the size of 1/30
of an inch. They were then furnished with a completely-formed digestive
apparatus. Davaine kept the intra-chorional embryos alive in water for
five or six years. His experiments on rats, dogs, and on a cow, led
to no decisive results; but it is important to know that the eggs of
lumbricoids effectually resist dryness. According to Davaine, however,
embryonal development is thus arrested (except in _Ascaris tetraptera_
of the mouse).

Seeing how readily the most ordinary attention to cleanliness must
suffice to prevent lumbricoid helminthism, it is scandalous that so
many severe cases of disease from this source should ever and anon turn
up and be reported. In no properly conducted stable are these large
entozoa ever to be seen in any considerable numbers; for so long as
the water-supply is good and the fodder clean there is no possibility
of infection. A fertile source of infection, however, results from
allowing horses to drink at foul road-side ponds and from open waters
in the vicinity of stables and paddocks where foals are reared. Into
the clinical bearings of the subject I do not enter, but a host of
interesting records of lumbricoid disease may be found in veterinary
journals, both home and foreign. These have their counterpart in the
very similar cases recorded in the medical journals, and quoted by me in
the 34th bibliography of this work. From Sonsino’s report these worms
do not appear very common in Egypt, but the veterinary inspector, Dr
Zunhinett, had occasionally met with them. From Messrs W. Awde, J. B.
Wolstenholme, and other English veterinary surgeons, I have received
notes of interesting cases, but in this connection I can only further
refer to the published cases of Messrs Anderson, Boddington, Cartwright,
Harrison, Moir, and Wallis. The French cases, by M. Cambron and by
M. Véret, are particularly instructive. Many of the cases give fatal
results. In one fatal instance a pupil of mine counted over 1200 of
these worms, and in a similar fatal case Mr Lewis reports that he found
the small intestine literally crammed, some thousands of worms being
huddled together in large masses.

[Illustration: FIG. 65.--Head of _Oxyuris curvula_. Highly magnified.
After Busk.]

The next nematode of general interest is the pinworm (_Oxyuris
curvula_). Professional men often confound it with the palisade worm,
and it has even been mistaken for the rat-tail maggot (_Helophilus_).
The longest males measure 1-3/4″, and the females often beyond 4
inches. This worm infests the colon in great numbers, the species being
easily recognised by its long subulate tail. Like its much smaller
congener infesting man, this worm occasions severe local irritation,
clusters of the eggs often accumulating to form yellow incrustations
at the verge of the anus. Equine pinworms are vegetable feeders, and,
like human Oxyurides, are conveyed to the bearer in a direct manner.
No horse properly looked after can be infested by these worms. Local
washings and stable cleanliness being secured by an attentive groom, the
animals are safe. Prophylactic measures of this kind are all-powerful
against infection. Notwithstanding the ease, however, with which the
oxyuris disorder may both be prevented and cured, we find it prevails
extensively everywhere, alike in mankind and in solipeds. Dr Sonsino
found these parasites abundant in Egypt, some of the worms reaching
a length of nearly five inches (120 mm.). Mr Emmerson has given an
interesting account of the prejudicial effects of these entozoa in the
horses of Singapore.

One of the most remarkable equine parasites is that which I am in the
habit of calling the large-mouthed maw-worm (_Spiroptera megastoma_),
in contra-distinction to the small-mouthed species (_S. microstoma_).
In this country the worm has attracted little notice, but through the
kindness of Mr Spooner Hart, of Calcutta, and of Mr Percivall, of the
11th Hussars, stationed at Umballa, I have had abundant opportunities
of examining this entozoon and the singular pathological appearances
which it occasions. This parasite was first described by Rudolphi,
who says:--“Spiroptera capitis discreti ore magno nudo, cauda feminæ
rectiuscula acuta, mavis simpliciter spirali, corpusculis rotundis ad
basim penis styliformis.” The worm was afterwards observed by Schultze,
Chabert, and frequently also by Andral, but the best accounts of it are
those given by Gurlt, Valenciennes, and Dujardin. Schneider has likewise
done much to set at rest disputed points. Respecting the _Spiroptère du
Cheval_, Dujardin, writing in 1844, observes that “Rudolphi at first
studied this helminth from examples found in great number by Reckleben,
at Berlin, in tubercles of the stomach of two horses. Quite recently,
M. Valenciennes, at Paris, has found it frequently in tumours, from
twenty to forty millimètres in size, in the stomach of eleven horses
out of twenty-five that he had subjected to this kind of research.
These tumours, lodged between the mucous and muscular layers of the
digestive canal, are perforated by several holes traversing the mucous
membrane. They are divided internally by a number of folds into numerous
intercommunicating cavities, and sometimes filled with solid mucus and
very many spiropteras. It is from examples collected by M. Valenciennes
that I have been able to study the parasite.”

As regards the description of the worm, it is almost needless to say
that Dujardin’s account is minute and admirable in all respects. In
fact, no naturalist ever exceeded the Rennes _savant_ in carefulness
and accuracy of detail. An interesting point connected with these
stomach-worms lies in the circumstance that Gurlt recognised two
varieties, one of which he termed _Sp. meg._, var. _major_. It remained
for Schneider to show that the larger worms formed an altogether
distinct species, which he termed _Filaria microstoma_ (‘Monogr.,’ l.
c., 1866, s. 98). It was not unnatural that Rudolphi and his successors
should confound these two forms together, and it is also not a little
curious that the smaller of the two species has the larger mouth.
Practically, veterinarians will probably rest content to know that
whilst the _Spiroptera megastoma_ occupies tumours in the walls of the
stomach, the _S. microstoma_ is always to be found free in the cavity
of that organ. Any helminthologist who may chance to have read the
Ceylon Company’s report on the fatal epidemic affecting the mules
of the Mauritius in 1876 can scarcely fail to have observed that the
worm called _Ascaris vermicularis_ by Mr Bradshaw is none other than
our _Sp. megastoma_. The description of the tumours as “reticulated”
sufficiently explains their honeycomb-like appearance, but I think that
the expression “alveolar” would better convey their true pathological
character. Mr Spooner Hart compared these structures, which he terms
“abodes,” to mole-hills, but there is no good ground for supposing that
the wanderings of the parasites are in any sense comparable to the
burrowings of the mole. In like manner the expression “nidus,” employed
by Mr Bradshaw, though suggestive of their nest-like appearance, is
to some extent misleading, as it implies that the worms form a nide
or brood. Possibly, it may turn out that all the nematodes in each
tumour have been bred in the spot where they are found, but hitherto
they have only been seen in the adult state. Earlier stages of growth
should be diligently sought for. Widely dissimilar as the two maw-worms
are, it would not greatly surprise me to learn that _Sp. megastoma_
and _S. microstoma_ are dimorphic conditions of one and the same
entozoon. At all events, Ercolani’s determination of the relations
subsisting between _Ascaris inflexa_ and _A. vesicularis_ suggests a
possible analogy of this kind. I may mention that the male _Spiroptera
megastoma_ reaches nearly one third and the female one half of an inch
in length. A constriction separates the head from the body. The mouth is
surrounded by four thick horny lips, the dorso-ventral pair being the
larger. The tail of the male is spirally twisted, and furnished with
lateral bands supported by three or four ribs. It carries two curved
spicules of unequal size. There are five pairs of caudal papillæ, the
tail being bluntly pointed in both sexes. The vulva of the female is
placed about 1/7″ below the head. The eggs are linear or very narrow,
and furnished with thick shells. According to Sonsino, who found _Sp.
megastoma_ in five out of sixteen Egyptian horses, the verminiferous
growths are usually seated near the pyloric end of the stomach, as many
as four tumours occurring at one time. Neither Sonsino nor any other
observers already quoted appear to think that these morbid changes in
any way interfere with the healthy performance of the gastric functions.
However, I am of opinion that at least one recorded fatal case of
parasitism, producing rupture of the stomach, affords an instance,
however rare, of the injurious action of this entozoon. It is reported
under the signature of “Argus,” quoted below.

In this connection I may mention that in 1864 Prof. Axe observed some
small worms, scarcely visible to the naked eye, in the mucous membrane
of the stomach of a donkey, the same worms being subsequently observed
in three other donkeys brought to the dissecting room of the Royal
Veterinary College. From the examination of a drawing of one of the male
worms, executed by Prof. Simonds, I am led to believe that the parasites
are entirely new to science. The hood being well marked there can be no
doubt as to the strongyloid affinities of the worm. I therefore propose
to call the worm after its discoverer (_Strongylus Axei_).

In regard to _Sp. microstoma_, the males measure up to 2/3″, whilst
the females have a long diameter of 3/4″ or rather more (10‴). The
small-mouthed maw-worm lives free in the stomach, and, as Krabbe
observes, not unfrequently in very considerable numbers. It does not
appear to be capable of injuring the host.

One of the most interesting equine nematodes is the eye-worm. Most
veterinary writers speak of it as the _Filaria oculi_, but to
helminthologists it is better known by the more correct designation, _F.
papillosa_. Though commonly obtained from the eyeball and its tunics,
the worm infests various tissues and organs of the body, being found
in the thorax, abdomen, membranes of the brain, muscles, and cellular
tissues. It infests the ass and mule, and also horned ruminants. The
males attain a length of three inches and the females seven inches. The
head is broad, with a gaping mouth armed with a ring of chitine and two
prominent denticles. There are also two papillæ on the neck near the
middle line, besides sixteen caudal papillæ, eight on either side. The
tail of the male is spirally twisted, that of the female only slightly
curved. Notwithstanding the many opportunities afforded of examining
this parasite in the fresh state, very little is known respecting its
origin and course of development. Dr Manson, who found that the mouth
was armed with a five- or six-toothed oral saw, considers that the eye
is not a proper resting place for the parasite, and that when one
wandering worm comes across the track of another it follows it up from
sexual instinct, and thus several may be found together in one place.
The tracks are readily seen by the naked eye. Dr Sonsino speaks of it
as a “yellow line.” This Italian observer found the worm in twelve
out of the sixteen solipeds he examined during the plague. Each horse
showed from two to a dozen worms “in the peritoneal cavity, wandering
free on the serous lining, without causing any apparent mischief to
the membrane.” On one occasion Sonsino found the worm in the liver.
From the similarity of habit there can be little doubt that the cases
of guinea-worm (_F. medinensis_) recorded by Clarkson and others, as
occurring in the horse, were merely examples of _F. papillosa_. I think
so all the more because the lamented Fedschenko verbally expressed to me
his astonishment that I had in my introductory treatise (p. 387) spoken
of the Dracunculus as an equine parasite. I did so on the authority of
others. To the Rev. Horace Waller I am indebted for specimens of the
eye-worm brought from Assam, and to Mr Spooner Hart for others sent from
India. For examples occurring in England I am indebted to Mr Haydon
Leggett, who, in 1875, sent me three specimens extracted from the eye
of a five-year-old mare. Mr Steel has also given me an example of _F.
papillosa_ taken from the peritoneum of a donkey. Similar cases are
constantly occurring in the practice of veterinarians in Hindostan.
Highly interesting Indian cases are recorded by Kennedy, Molyneux,
Twining, and Breton, and in addition to these I may also particularise
those of Macnamara, C. Percivall, Hickman, Clarkson, Skeavington, and
Jeaffreson. The cases by Lee and Grellier also deserve attention.

Another species of thread-worm (_Filaria lacrymalis_) is occasionally
found in the horse between the lids and eyeball. It is a comparatively
small and harmless parasite, the males measuring 1/2″ in length and the
females 2/3″. It also infests the ox. Both the large and small eye-worms
are viviparous, and, not improbably, both of them are the means of
conveying embryonic Filariæ into the circulation. Be this as it may, we
owe to Dr Sonsino the discovery of hæmatozoa in an Egyptian horse. The
larval worm was provisionally named by him _Filaria sanguinis equi_.
The microscopic nematodes closely resemble the larvæ of _F. sanguinis
hominis_, but they are smaller. The horse from whose blood Dr Sonsino
obtained the minute worms was also found, by post-mortem examination,
to have been infested by _Filaria papillosa_, a circumstance which
naturally suggested a genetic relation between the larval and adult
parasites. Similar, if not the same, microscopic worms had been
previously discovered by Wedl, who primarily and independently regarded
them as embryos of _F. papillosa_. Another curious filaria-like entozoon
is the reticulated threadworm (_Onchocerca reticulata_). In England we
have no acquaintance with this singular parasite, but it appears to be
tolerably common in Italy. Excellent figures of it have been given by
Diesing. Both males and females are in the habit of coiling themselves
within the muscles, where they are found invested by a capsule of
connective tissue. When unrolled the sexes are found of equal size,
acquiring a length of 1-1/2″. The worm has a simple unarmed mouth, its
body being marked by a series of annulations formed of incompletely
anastomosing rings. It does not appear to possess any clinical
importance.

In connection with the equine nematodes I need only mention the
lung-worm (_Strongylus micrurus_). Its importance in relation to the
production of husk or parasitic bronchitis in calves has already been
considered. The worm is rarely productive of mischief amongst solipeds,
nevertheless, in the dissecting-room subjects at the Royal Veterinary
College, the presence of these parasites in the lungs is frequently
noticed. Lastly, it only remains for me to observe that the renal
strongyle (_S. gigas_) is occasionally seen in the horse. In 1792 M.
Chabert found one in the left kidney, and similar cases have since
either been witnessed or reported by Rudolphi and Leblanc.

Of the numerous insect parasites and tormentors of solipeds the gadflies
(_Œstridæ_) demand chief attention. For special description of the
forms, Brauer’s monograph is the most, and, in fact, the only reliable
authority. Here it is not possible to give the characters of the various
equine species, of which at least half a dozen are known to science. As
remarked by me in the special chapter contributed to Prof. Williams’
well-known veterinary treatise, the common gad-fly (_Gastrophilus equi_)
attacks the animal whilst grazing late in the summer, its object being,
not to derive sustenance, but to deposit its eggs. This it accomplishes
by means of a glutinous excretion, causing the ova to adhere to the
hairs. The parts selected are chiefly those of the shoulder, base of the
neck, and inner part of the fore legs, especially about the knees, for
in these situations the horse will have no difficulty in reaching the
ova with its tongue. When the animal licks those parts of the coat where
the eggs have been placed, the moisture of the tongue, aided by warmth,
hatches the ova, and in something less than three weeks from the time
of the deposition of the eggs, the larvæ make their escape. As maggots
they are next transferred to the mouth, and ultimately to the stomach
along with food and drink. A great many larvæ perish during this passive
mode of immigration, some being dropped from the mouth, and others being
crushed in the fodder during mastication. It has been calculated that
out of the many hundreds of eggs deposited on a single horse, scarcely
one out of fifty of the larvæ arrive within the stomach. Notwithstanding
this waste the interior of the stomach may become completely covered
with “bots.” Whether there be few or many, they are anchored in this
situation chiefly by means of two large cephalic hooks. After the bots
have attained perfect growth they voluntarily loosen their hold, and
allow themselves to be carried along the alimentary canal until they
escape with the fæces. Many persons suppose that during their passage
through the intestinal canal they re-attach themselves to the mucous
membrane, thereby occasioning severe intestinal irritation. This is an
error. In all cases they sooner or later fall to the ground, and when
transferred to the soil they bury themselves beneath the surface, in
order to undergo transformation into the pupa condition. Having remained
in the earth for a period of six or seven weeks they finally emerge
from their pupal-cocoons as perfect dipterous insects. It thus appears
that bots ordinarily pass about eight months of their lifetime in the
digestive organs of the horse.

That they are capable of giving rise to severe disease there can be no
doubt, but it is not often that the disorder is correctly diagnosed,
since it is only by the passage of the larvæ that the practitioner can
be made aware of their presence. Mr J. S. Wood has published a case of
tetanus in a mare, associated with the larvæ of _Œstrus equi_, and Mr
J. T. Brewer has also given a case where the duodenum was perforated
by bots. Mr Goodworth records an instance of pyloric obstruction from
the same cause, and Mr W. Coupe informed me in 1876 that he had a drove
of foreign ponies under his care, all of which suffered irritation
from hæmorrhoidal bots. He removed them with a pair of forceps.
Although frequently said to do so, the common bot does not attach
itself to the rectum before finally escaping the host. The larvæ of _G.
hæmorrhoidalis_ normally reside there. In this situation they seriously
inconvenience the bearer. The bots of _G. nasalis_ are often confounded
with those which ordinarily occupy the stomach of the bearer. The larvæ
of _G. nasalis_ commonly reside in the duodenum near the pylorus.
According to Schwab and Brauer, they rarely occupy the stomach. As
occurs in the common species, this bot passes away with the fæces, and
does not attach itself to the lower bowel. The bots of Brauer’s _G.
inermis_ much resemble those of _G. equi_, but they are much smaller
and attach themselves to the wall of the small intestine. The bots of
_G. pecorum_, which dwell in the rectum, are readily recognised by
their peculiar form and scanty spination. They are pointed in front
and truncated posteriorly. An assinine variety of _G. equi_ has been
described by Bilharz, whilst another distinct species (_G. flavipes_)
attacks the ass and mule. The bot-larvæ of the latter host require
recognition and description. A great variety of other equine bot-flies
have been described, but all, or nearly all, of them are mere synonyms
of the above-mentioned forms. For the limitation of the species I accept
Brauer’s authority, and likewise his nomenclature. A great deal of
nonsense has been written respecting bots. It is a relief to believe
that _G._ (Œstrus) _veterinus_, _G. ferruginatus_, _G. jubarum_, _G._
(Œ.) _Clarkii_, _G. salutiferus_, _G. subjacens_, and many others, are
not good species, at least that they are mere synonyms. In regard to
the occurrence of subcutaneous bot-like maggots in the horse and ass,
no doubt need exist on this point. I am indebted to Mr Percy Gregory
for characteristic specimens taken from the back, neck, and withers of
a four-year-old gelding. They appear to correspond with the _Hypoderma
Loiseti_ of Joly. Similar maggots have been found in the ass by Herr
Erber, but Brauer refers these to _H. silenus_. Prof. Brückmüller
published a case where the brain was infested by larvæ; and Mr Shipley
has sent me an example of _H. equi_, which he states he removed from
the choroid plexus of the brain. In addition to the cases by Woods,
Goodworth, and Brewer, already quoted, others have been published by
Tyndal and Cartwright.

Amongst the numerous other parasitic dipterous larvæ one must notice the
rat-tailed maggots (_Helophilus_). A genuine instance of this kind has
been brought under my observation, but the example recorded by Professor
Axe was spurious. Professor Simonds and myself saw this supposed maggot,
which was merely a very stout and pregnant _Oxyuris curvula_. Another
genuine case was published by Mr. Stanley. This is quoted by A. Numan in
his essay on _Cœnurus_. I have previously mentioned my having received
an Helophilus-larva that had passed from the human body. One of the
most troublesome external parasites is the so-called horse-tick or
forest-fly (_Hippobosca equina_). They attack the abdomen, flanks, and
inner part of the thighs in great numbers, occasioning great distress
to the bearer. Being of leathery toughness their bodies are not easily
crushed, and they are removed only with great difficulty. There is
an equine disease in Sweden called _Stackra_, which is erroneously
attributed to injuries produced by a species of fly-maggot (_Lixus_)
which lives on the fine-leaved water-drop wort (_Phellandrium_). As
regards the so-called free parasites, or rather non-parasitic obnoxious
insects, which torment solipeds, it is impossible even to enumerate
them. The tsetse of South Africa (_Glossina morsitans_) is terribly
fatal to the horse, but it is said that the mule, ass, and zebra
do not suffer from its bites--an immunity shared by swine, goats,
antelopes, and man himself. Major Vardon’s rash experiment (based on
the supposition that horses deprived of fresh green food would not
suffer from the attacks of the fly) proved fatal to an animal which he
purposely exposed on a much infested hill-top. The horse died ten days
after it was bitten. According to Chapman, the bites of four tsetse
flies are sufficient to kill an ox, but in man the irritation produced
is very slight. Amongst other insects proving troublesome to solipeds
may be mentioned the leg-sticker (_Stomoxys calcitrans_), the clegg
(_Hæmatopota pluvialis_) which is very abundant in the West Highlands,
various species of _Tabanidæ_ and _Asilidæ_ (_Tabanus autumnalis_, _T.
bovinus_, _Chrysops cæcutiens_, _Asilus crabroniformis_), and also a
host of ordinary flies and gnats (_Muscidæ_ and _Tipulidæ_), as, for
example, _Anthomyia meteorica_ and _Culex equinus_. In India the bite
of a species of _Simulia_ gives rise to the formation of open sores of
the most intractable character. As regards hemipterous insects it may
be said that many species of lice (_Anoplura_) produce what is called
phthiriasis or lousiness in the horse, some of them being derived
from poultry. The best known species are _Trichodectes equi_, _T.
scalaris_, _Hæmatopinus equi_, _H. vituli_, _H. eurysternus_, and the
ass-louse (_H. asini_). Of the half dozen or more species infesting the
hen (belonging to the genera _Goniocotes_, _Liotheum_, &c.) it is not
probable that more than one or, at most, two of them are concerned in
the production of poultry-lousiness in the horse. As an equine disorder
this kind of phthiriasis was first described by Bouley. Cases in England
have been observed by Messrs. Henderson, Moore, and Woodger. For some
account of cases of lousiness due to _Hæmatopinus_ I am indebted to
Mr S. Butters. As regards the scab, itch, and mange insects or mites
(_Acaridæ_), three perfectly distinct forms are known. Adopting M.
Mégnin’s classification they are _Sarcoptes scabiei_, var. _equi_,
_Psoroptes longirostris_, var. _equi_ (being the _Dermatodectes equi_
of Gerlach), and _Chorioptes spathiferus_, var. _equi_, which is the
_Symbiotes equi_ of Gerlach. All the species have been beautifully
illustrated by M. Mégnin, whose memoir has dispersed many of the
clouds of error and misrepresentation which have hitherto surrounded
the subject. Whilst _Psoroptes_ forms the true horse-mite, and attacks
various parts of the body, _Chorioptes_ confines its attacks to the
posterior regions. Messrs South and Day and myself have verified some
of the facts recorded by Mégnin in respect of the structure and habits
of this last species. Another kind of mite (_Glyciphagus hippopodos_)
is stated to infest the ulcerated feet of horses. It would appear that
no true ticks properly belong to solipeds; nevertheless, the common
cattle-tick (_Ixodes bovis_) occasionally attacks horses. Probably
several other species of Ixodidæ, known to infest other animals, behave
in the same way. The Arachnidan called _Pentastoma tænioides_, though
properly belonging to the dog, has on several occasions been detected in
the nasal or frontal sinuses of the horse. Such instances are recorded
by Chabert and Greve. The largest example of this singular entozoon seen
by myself was obtained from the same situation, and presented to me
by the late Mr C. B. Rose, whose writings I have frequently quoted in
connection with the _Cœnuri_ of rabbits.

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‘Veterinarian,’ 1866, p. 265.--_Woodger_, “Hydatid in the Brain of a
Horse,” ‘Veterinarian,’ 1863, p. 75.--_Woods, J. S._, “Tetanus in a
Mare, associated with the Larvæ of _Œstrus equi_ within the Stomach
and Duodenum,” ‘Veterinarian,’ 1859, p. 693.--_Wright_, “Strongyli in
the Scrotum of a Colt,” ‘Veterinary Record,’ 1849, p. 385.--_Youatt_,
“Worms between the Tunics of the Stomach,” ‘Veterinarian,’ 1835, p.
571.--_Idem_, “Tetanus, Worms in the Trachea, and Dilatation of the
Heart, in a Zebra,” _ibid._, p. 504, 1836.--_Idem_, “Worms in the Nasal
Cavity of the Horse,” _ibid._, p. 329, 1832.--_Zangger_, “Remarks on
Entozoa,” from the French, ‘Veterinarian,’ 1855, p. 463.


PART X (PACHYDERMATA)

Concerning the parasites and parasitic diseases of this miscellaneous
assemblage of large mammals, I shall first speak of those of the
proboscideans (Elephantidæ). Except by myself, they have been but
little studied, and I am yet waiting for an opportunity to give further
time to their consideration. When Diesing published his ‘Systema’ only
two helminths were referred to the Indian elephant, namely, _Ascaris
lonchoptera_ and an undescribed fluke supposed to be a distome. The
whole subject requires revision, but I think the following species must,
for the present at least, be allowed recognition:--_Fasciola Jacksoni_
(mihi), _Amphistoma Hawkesii_ (mihi), _Ascaris lonchoptera_ (Diesing),
_Sclerostoma Spinuliferum_ (Baird), and _Dochmius Sangeri_ (mihi).
Either the _Ascaris_ or the _Sclerostoma_ is probably identical with
Rudolphi’s _Strongylus elephantis_.

At the Norwich Meeting of the British Association, in 1868, I exhibited
two flukes received from J. S. Thacker, V.S., of the Madras Army. They
were handed to me by the late Dr Baird, and were labelled “Distoma
taken from liver of elephant and forwarded for classification.” I
stated at the time that these entozoa were identical with certain
flukes previously obtained from the duodenum and biliary ducts of an
Indian elephant, and which, though carefully preserved in the Boston
Museum, U.S., had never been properly described. They were only briefly
noticed by Dr Jackson in his ‘Descriptive Catalogue’ of the Museum. In
the summer of 1868 fifteen specimens of fluke, removed from Burmese
elephants, had been forwarded to and received by Professor Huxley
from Rangoon, accompanied by a statement to the effect that they were
the cause of an extensive and fatal disease in Burmah. Through the
kindness of Prof. Huxley I was allowed to make use of his specimens
for the purpose of comparison and identification, and thus it became
evident that our specimens were of the same species. It was also evident
that the species could be none other than that represented by the
Boston specimens. Further examination having made it clear that the
organisation of these flukes departed from the ordinary distome type, I
named the parasite _Fasciola Jacksoni_, at the same time offering the
following description (‘Entozoa,’ Supp., 1869, p. 80):--“Body armed
throughout with minute spines, orbicular, usually folded at either end
towards the ventral aspect, thus presenting a concavo-convex form; oral
sucker terminal, with reproductive papillæ about midway between it and
the ventral acetabulum; intromittent organ 1/4″ in length; digestive
apparatus with two main zigzag-shaped canals, giving off alternating
branches at the angles thus formed, the ultimate cæcal ramifications
occupying the whole extent of the body; length, when unrolled, from
1/2″ to 5/8″, breadth 1/3″ to 1/2″.” Now, if reference be made to the
appendix of the late C. M. Diesing’s ‘Systema Helminthum,’ it will be
found that Jackson’s statement had not escaped that helminthologist’s
notice, though, not having seen any specimens, he was not unnaturally
led to place the species amongst the distomes proper. In Diesing’s
subsequently published ‘Revision der Myzelminthen,’ the species
is formally characterised as the _Distomum elephantis_ of Jackson
(‘Sitzungsberichte d. Math.-nat. Cl. d. k. Akad. d. Wissenchaften,’ Bd.
xxxii, 1858). In my “Synopsis of the Distomidæ,” which appeared in the
‘Journal of the Linnean Society’ for 1861, I had also placed it amongst
the distomes, not considering it to be a doubtful form (‘Proceed.
Linn. Soc.,’ “Zoology,” vol. v, p. 9). These references exhausted the
literature of the subject up to the time of the issue of my ‘Manual’
in 1873, where this fluke is again briefly noticed (p. 13). Several
of Prof. Huxley’s specimens have been added to the entozoological
department of the Hunterian Museum. It is clear that all these notices
and descriptions point to the same parasite. The worm has since been
more carefully described by Dr R. H. Fitz, from a series of dissections
and preparations made by Dr H. P. Quincy, and deposited in the Warren
Museum, Boston, U.S.

About the middle of June, 1875, I received a letter from General Hawkes,
of the Madras Staff Corps, dated Secunderabad, May 12th, 1875, and in
reference to the subject before us he writes as follows:--“My attention
has been recently directed to a very unusual mortality of elephants
at this station. Out of twenty-eight elephants under my charge, no
less than twelve have died within the last sixteen months, whereas the
average annual mortality has been hitherto only two per annum out of
thirty-eight in our establishment. In every case of death there appeared
to exist serious organic disease quite sufficient to account for such
death, but as the mortality increased I had a post-mortem examination
made in each case; and although here also organic disease sufficient
to account for death was present in each case, yet in every one of
these elephants we found the liver-fluke in greater or less abundance.”
General Hawkes adds:--“Meanwhile I have sent you a small box containing
three bottles, one containing the liver-fluke (_Fasciola Jacksoni_)
referred to in your work on the parasites of domesticated animals. It
seems possible that the other two species of parasites may not have
been brought to your notice. Both of these, namely, the “masuri” and
the “soorti,” are very common in elephants. They are both found in the
intestines only. The “masuri,” when present in any quantity, cause
considerable disturbance, and the animal instinctively resorts to the
_eating of earth_, which it consumes in large quantities until the
bowels are acted on and the worm expelled. The soorti is more common
than masuri, and does not seem to inconvenience the animal very much.
When expelled from the animal the soorti is a round white worm, like
most of the threadworms; the masuri, on the other hand, is of a delicate
flesh color.” Shortly after the receipt of this letter I obtained the
entozoa in a good state of preservation. Accordingly I wrote to General
Hawkes, stating that the flukes were clearly referable to _Fasciola
Jacksoni_; that the parasites to which the natives of Hindostan apply
the term “soorti” were evidently examples of _Ascaris lonchoptera_
(Diesing), previously called strongyles by Rudolphi; and that the
worms which he called “masuri” were trematodes new to science. I named
the species _Amphistoma Hawkesii_, in honor of the donor. The bottle
contained as many as forty-nine specimens. I may here remark that I
have made inquiries of the keepers of the elephants at the Zoological
Gardens as to whether they have ever seen entozoa that were passed by
the animals under their care. They replied in the negative, the keeper
of the African elephants (Scott) having made frequent inspection of the
fæces. I was the more anxious to secure information on this point since,
during my frequent visits to the menagerie, I had observed that the
African elephants were in the habit of swallowing large quantities of
mud and dirt from small hollows in the ground near the great water-tanks
in which they bathe. Prof. Garrod (who had dissected three elephants)
also assures me that there has been no trace of an entozoon in any of
the Indian elephants examined by him. In one dissected at Edinburgh
the same negative result was obtained. From the facts at present in
my possession, I conclude that the habit of earth-eating, displayed
alike by Indian and African elephants (and, as stated in my account of
the equine parasites, shared by horses), is not necessarily due to the
presence of parasites. I apprehend rather, that it is resorted to by
these animals under any circumstances of intestinal irritation, whether
created by entozoa or other foreign agents. The notion of the elephant’s
intelligent self-cure by eating earth is a very old fable. Captain
Forsyth, as quoted by Mr Fleming, alludes to it in his ‘Highlands of
Central India,’ and I find the same ideas recorded by Williamson and
Howitt. Forsyth says:--“Elephants are very liable to intestinal worms.
They generally cure themselves by swallowing from ten to twenty pounds
of earth.” Captain Williamson says:--“They are much troubled with
worms, for the cure of which the elephant eats earth. If the dung be
inspected there will be seen an amazing number of moving objects, which
much resemble pieces of chewed sugar-cane.” Some excellent practical
remarks are added, testifying to the value of the native remedy called
_Kallah-nimok_, or _bit-noben_, which is a saline purgative. In Lieut.
Ouchterlony’s essay (quoted below) no allusion is made to the subject of
worms.

General Hawkes afterwards supplied me with further information. In a
letter from Secunderabad, dated July 30th, 1875, he says:--“As regards
the liver-fluke (_F. Jacksoni_), it appears from your treatise to
have been first observed in 1847. The only other published notice
that I have been able to find of it is contained in a letter to a
newspaper, dated ‘Rangoon, 16th July, 1867,’ and is signed ‘R. B.’
In this letter the unusual mortality of seven elephants in about
fifteen days is attributed to the presence of this liver-fluke, the
two other parasites (_Amphistoma_ and _Ascaris lonchoptera_) being
also present in the intestines.” “Now (continues General Hawkes), in
every case at which I was present _flukes were found in greater or
less numbers_ in the gall-ducts of the liver, and the _Amphistoma_ was
also as constantly present in the intestines, the soorti (_Ascaris
lonchoptera_), contrary to the general experience of the elephant
attendants, being less frequently met with, though from its color and
slender shape it is not so easily detected among the huge mass of
fæces as the larger _Amphistoma_.” Speaking of the amphistoma General
Hawkes says:--“This internal parasite is well known to all who
possess elephants. It is alluded to by Dr Gilchrist in his treatise on
the ‘Diseases of Elephants,’ first published in 1841, but he merely
mentioned it under its local name, _masuri_, and made no attempt
either to describe it scientifically or to ascertain its place in the
natural system. As far as my experience goes it is only found in the
intestines. These parasites appear to be very generally present in the
elephant. When their numbers are few the ‘host’ is probably not much
inconvenienced, but when present in any great quantity they undoubtedly
cause much irritation. When this is felt, the animal, as before
remarked, instinctively resorts to a simple and effectual remedy. He
eats a quantity of earth, which purges him thoroughly and expels the
amphistoma. The mahawats are of opinion that whilst the elephant is
eating earth to relieve himself of the pests the daily allowance of rice
should be scrupulously withheld; and they say that if the rice, which
is given uncooked, is eaten by the animal under these circumstances,
excessive purgation is induced, which frequently results in death.
How far this opinion is founded on fact I am unable to say, but the
mahawat’s name for this disease means ‘fasting,’ and bears testimony to
the generally received notion of the necessity of withholding the rice
when the animal is eating earth.”

When describing the parasites of the horse (p. 358), I spoke of
Collins’ amphistome from that animal, but in the letter addressed to
me from Simla, 22nd March, 1875, Mr. Collins made no allusion to the
earth-eating habit. He wrote:--“I forward you by this mail parasites
found in the colon of a horse that died, a subject of fever peculiar to
this country. There were _about a thousand_ of the parasites, and nearly
the whole of them were situated close to the cæcum, and were loose in
the gut. Not having seen parasites at all similar to these, I have
forwarded them for identification. They were of a brick-red color when
first obtained.” These explicit statements by Mr Collins are interesting
from many points of view. One has only to place his specimens side
by side with those from the elephant in order to satisfy one’s self
that the two forms are distinct. For the reasons already stated I
provisionally called the worm _Amphistoma Collinsii_. It is probable
that other veterinary surgeons have encountered this entozoon in India;
but, unless they can point to some published account of the fact, Mr
Collins is entitled to be considered as its discoverer. Doubtless many
other European residents in India, Ceylon, and Burmah, must, like Dr
Gilchrist, be well acquainted with the _masuri_ as such, though unaware
of their zoological position.

In a record of the post-mortem examination of one of the victims of the
Secunderabad epizoöty, the veterinary surgeon said:--“No doubt disease
of the lungs and subacute inflammation of the bowels were the immediate
cause of death, but the large number of flukes in the liver and the
intestinal parasites (_i. e._ the amphistomes) account in a great
measure for some of the symptoms shown, and these symptoms accord in
many respects with those shown in elephants that died in Burmah during
the epizoöty (rot) in 1867, as recorded by R. B., notably, refusal of
food, standing with mouth open, restlessness, and puffiness about the
head and shoulders. The liver parasite is no doubt the same referred
to by R. B., and is that termed by Dr Cobbold _Fasciola Jacksoni_.” In
reference to a later case the same officer remarks:--“I carried out
the post-mortem examination with special reference to inquiry as to the
probability of the mortality amongst elephants at this station being
of parasitic origin. This was suggested to me by the former case. The
post-mortem appearances differed in every respect. There were flukes in
the liver, but in no great quantity, and the structure of the liver was
sound. Although not assisted by this case in attributing the mortality
to parasitic origin, I am strengthened in my opinion that the death
of the previous elephant was due to disease caused by the presence of
the liver fluke.” This report, by Mr W. S. Adams, is to some extent in
harmony with later information. An epizoötic outbreak amongst elephants
has occurred in England, at Sanger’s Circus, and I had opportunity to
examine one of the dead animals. In my own opinion, and in that of Mr F.
Smith, the veterinary surgeon who attended the animals professionally,
the disease was due to parasites. I obtained large quantities of
_Amphistoma Hawkesii_ from the intestinal canal, and also other worms.
The death of one of the elephants was made the subject of litigation,
when, as might be expected, great diversity of opinion as to the cause
of the fatal issue prevailed.

Mr Smith, an old pupil of mine, regarding the amphistomes and strongyles
as the cause of death, wrote to the effect that “some of the worms were
found between the coats of the intestine, and others on the free surface
of the gut, whilst the excretory ducts of some of the glands were found
blocked with them.” The animal examined by myself on the 24th of August,
1876, yielded numerous examples of _Amphistoma Hawkesii_, _Ascaris
lonchoptera_, and _Dochmius Sangeri_, the last species being so named
by me after the owner of the circus who lost the herd of elephants by
the epizoöty. The male _Dochmii_ measured 5/8 and the females 3/4 of an
inch in length. Here I must reluctantly quit the helminths of elephants,
adding only an expression of surprise that Dr Max Schmidt should have
had so little to say concerning them in his otherwise instructive memoir
on ‘The Diseases of Pachyderms’ (quoted below).

I have but a few words to offer respecting the ectozoa. A species of
mite has been described whose generic position appears doubtful. I
allude to _Homopus elephantis_ of Fürstenberg, or _Symbiotes elephantis_
of Gerlach. According to Mégnin it is a _nymphe adventive_ or _hypope_
of a variety of _Tyroglyphus siro_. This acarus is abundant in old
forage. Another ectozoon is _Hæmatomyzus elephantis_. It differs
from the lice proper in many respects, but, according to Piaget, the
reproductive organs resemble those of _Hæmatopinus_. In ‘Science Gossip’
for June, 1871, Mr H. C. Richter describes “a new form of parasite,”
which is called _Idolocoris elephantis_. The insect, which was one line
in length, was found upon an elephant in Ceylon. According to Walker it
not only constituted the type of a new genus, but of an altogether new
family of the Hemiptera Heteroptera, coming very near to the bed-bugs
(_Acanthidæ_). It is a huge sucking louse. From the discussion which
followed, it seems that the parasite had several times been seen before,
and was none other than E. Piaget’s _Hæmatomyzus elephantis_. Excellent
figures accompany Richter’s and Piaget’s descriptions. Notwithstanding
Piaget’s explanation, I think the specific name, _longirostris_, would
have been a more appropriate appellation.

BIBLIOGRAPHY (No. 51).--(Anonymous), “Diseased Elephants,” see ‘Lancet,’
Sept. 2, 1876; also “Report of the Case at Law (Jamrach _v._ Sanger),”
given in the ‘Veterinarian,’ Dec., 1877, p. 886.--_Cobbold, T. S._,
“Description of a species of Trematode from the Indian Elephant, with
remarks on its Affinities,” ‘Quart. Micros. Journ.,’ Jan., 1869; see
also ‘Entozoa,’ supp., 1869, p. 80.--_Idem_, “On the Destruction of
Elephants by Parasites, with remarks on two new species of Entozoa and
on the so-called Earth-eating habits of Elephants and Horses in India,”
‘Veterinarian,’ Oct., 1875.--_Idem_, “Further Remarks on Parasites
from the Horse and Elephant, with a notice of new Amphistomes from the
Ox,” _ibid._, Nov., 1875.--_Diesing_ (l. c., in text).--_Fitz, R. H._,
“Anatomy of _Fasciola Jacksoni_,” ‘Rep. of Boston Soc. Med. Sci.,’ in
the ‘New York Med. Journ.,’ Nov., 1876.--_Fleming, G._, “The Diseases
of Elephants” (chiefly from Captain Forsyth’s work on the ‘Highlands of
Central India’), ‘Veterinarian,’ March, 1873, p. 181.--_Mégnin_, “Mém.
sur les Hypopes,” in Robin’s ‘Journ. de l’Anat. et de la Physiol.,’
1874 (_H. elephantis_), p. 248.--_Ouchterlony, J. W._, “An Essay on the
Management of the Elephant, and its Treatment in ordinary Diseases,”
‘Rep. of Vet. Med. Assoc.,’ Nov., 1872, and pub. in ‘Veterinarian,’
Jan., 1873, p. 65.--_Piaget, E._, “Description d’un parasite de
l’éléphant,” ‘Tijschrift voor Entomologie,’ 1869, p. 249.--_Richter,
H. C._, “A new form of Parasite (_Idolocoris elephantis_),” ‘Science
Gossip,’ 1871, pp. 131, 185, 211, 278.--_Schmidt, Max_, “Die Krankheiten
der Dickhäuter,” ‘Deutsche Zeitschrift f. Thiermed. und vergleichende
Pathologie,’ f. Nov., 1878, s. 360.--_Williamson, T._, ‘Oriental Field
Sports,’ London, 1807, vol. i, p. 138.

The parasites of the _Rhinoceridæ_ have been even less studied than
those of elephants. In 1856 Prof. Peters described a tapeworm from
Bruce’s rhinoceros (_R. Africanus_), which he named _Tænia gigantea_.
In 1870 Dr Murie, under the provisional name of _T. magna_, published
a description of the strobile of the same cestode from an Indian
rhinoceros (_R. unicornis_). From a total misconception of the character
of the proglottides, Murie was led to suppose that the segments of
the strobile were very deep as well as broad; whereas the proglottids
are remarkably narrow, thus partaking of the characters of the Tæniæ
of the larger herbivora in general. In a subsequent paper Peters
pointed out these errors. Murie had, in fact, rolled several segments
into one. In 1877 Professor Garrod encountered the same cestode in
_Rhinoceros sondaicus_, and, following Peters’ example, separated it
from the Tæniæ proper (_Plagiotænia gigantea_). The idea of generically
separating tapeworms possessing a more or less striking breadth of
strobile is not one which commends itself to my view, seeing that
many of the tapeworms of herbivora closely resemble the rhinoscerine
cestodes in this respect. As Diesing hints, this tapeworm comes near
to _T. perfoliata_, but Garrod’s and Peters’ figures both show that
_Plagiotænia_ wants the neck-lobes. The presence of cephalic appendages
may be regarded as generically distinctive, but it does not appear
that Blanchard separated the perfoliate tapeworm of the horse from the
Tæniæ proper on this ground. Therefore, in my account of the equine
tapeworms, I have not adopted his genus _Anoplocephala_. I may remark,
in passing, that if the distinctions, as between armed and unarmed, or
between proboscis-bearing (_Rhynchotæniada_) and non-proboscis-bearing
tapeworms (_Arhynchotæniada_), are to be maintained, they should
be expressive of divisional or subordinate value. Dr Weinland’s
arrangement, having reference to the thick- and thin-shelled ova
(Sclero- and Malaco-leptidota), is, perhaps, preferable. The whole
subject of classification requires revision, but it should be undertaken
by some helminthologists practically acquainted with a large number of
cestode types. As Garrod has well observed, _Plagiotænia_ enjoys a wide
geographical distribution, infesting alike Indian and African hosts.
Prof. Garrod, I observe, speaks of the _head_ of the mature tapeworm
as the _scolex_--an extension of the meaning of a term not usually
recognised. In this, however, he only follows Peters’ unfortunate
example.

The wide distribution enjoyed by Peters’ Plagiotænia is probably
equalled by that of the rhinocerine stomach-bot (_Gastrophilus
rhinocerontis_, Owen). This parasite was originally described in 1840,
and since that time it has been frequently encountered both in India
and Africa. To Mr Spooner Hart, of Calcutta, I am indebted for a large
number of specimens; their size exceeding that of any other bots that
have come under my notice. Probably this parasite infests the stomach of
rhinoceroses generally; at all events, it occurs in _R. unicornis_, _R.
bicornis_, and _R. simus_. At present the imago is unknown. The longest
larvæ in my possession measure 1-1/8″, but Brauer records specimens
up to 35 mm. in length by 10 mm. in thickness. In African hosts M.
Delegorgue found these parasites in prodigious numbers.

BIBLIOGRAPHY (No. 52).--_Brauer_, “Bot of the Rhinoceros,” ‘Monogr.
der Œstr.,’ 1863, s. 92.--_Cobbold_, “Note on Parasites presented
by Messrs Danford, Hart, and others,” ‘Veterinarian,’ 1875, p.
513.--_Coquerel_ and _Sallé_, in ‘Ann. Soc. Entom. de France,’ 1862
(quoted by Brauer).--_Delegorgue_, ‘Voyage dans l’Afrique’ (quoted by
Brauer).--_Garrod_, “On the Tænia of the Rhinoceros of the Sunderbunds
(_Plag. gig._, Peters),” ‘Proc. Zool. Soc.,’ Nov. 20, 1877, p.
788.--_Hope_, in ‘Trans. Entom. Soc.,’ 1840, p. 259.--_Joly, M. N._,
“Recherches Zool. (&c.) sur les Œstrides (&c.),” in ‘Ann. des Sciences
(&c.) de Lyon,’ 1846 (quoted by Brauer).--_Murie, J._, “On a probably
new species of Tænia (_T. magna?_) from the Rhinoceros,” ‘Proc. Zool.
Soc.,’ 1870, p. 608.--_Peters, W._, “Note on the Tænia from the
Rhinoceros, lately described by Dr J. Murie,” ‘Proc. Zool. Soc.,’ 1871,
p. 146.

Very little has been written respecting the parasites of the
_Hippopotamidæ_ and _Tapiridæ_. I think it was Livingstone who first
drew attention to the fact that the river-horse or sea-cow is much
infested by tapeworms, but I have not seen any published description of
the worm. Dr. Murie, during his sojourn in Egypt, found a solitary bot
embedded in the soft parts surrounding the eye, and judging from his
figure the species is new to science. Provisionally I speak of it as the
_Hypoderma Muriei_. In the paper (quoted below) Murie appends a list of
all the animals in which bots have been found. Though chiefly taken from
Brauer, it is useful and tolerably complete. So far as I am aware no
cestodes have been described as infesting tapirs; nevertheless, at least
five other kinds of helminth have been found in _Tapirus Americanus_.
Of these, two are flukes (_Amphistoma asperum_ and _A. pyriforme_),
and three are nematodes (_Sclerostoma monostechum_, _Spiroptera
mediospiralis_, and _Sp. chrysoptera_). The three species first named
occupy the cæcum, whilst the others are found in the stomach. According
to Molin’s description, both species occupy tuberous excrescences of
the mucous membrane, thus reminding us of the similar habit enjoyed by
_Sp. megastoma_ in the horse. The _Sp. chrysoptera_ is a comparatively
large species, the males measuring an inch, and the females as much as
an inch and a half in length. Both of the spiropteras were obtained from
tapirs by the indefatigable Natterer, _Sp. mediospiralis_ being also
procured by him from the aguti. If I have read Molin correctly, as many
as thirty-four examples of _S. mediospiralis_ were taken from a single
excrescence in the stomach of the tapir. Upwards of a hundred specimens
were procured, collectively, from three similar stomach-excrescences
in _Dasyprocta aguti_. These, and the other tapirine parasites above
mentioned, were originally discovered in Brazil.

BIBLIOGRAPHY (No. 53).--_Diesing_, “Neue Gattungen von Binnenwürmen
nebst einem Nachtrage zur Monographie der Amphistomen,” in ‘Annalen
d. Wien. Museums,’ Feb., 1839, s. 236.--_Idem_, ‘Systema,’ Bd. ii, s.
306.--_Molin_, “Una monografia del genere Spiroptera,” in ‘Sitzungsb.
der math.-naturw. Cl. d. k. Akad. d. Wissensch.,’ Bd. xxxviii, s. 1001,
1859.--_Murie_, “On a larval Œstrus found in the Hippopotamus,” ‘Proc.
Zool. Soc.,’ 1870, p. 78.

The osculant position of the anisodactyle pachyderms (_Hyracidæ_),
formerly classed as rodents, renders it desirable that their parasites
should be briefly noticed in this place. Probably these animals,
zoologically speaking, come nearest to the rhinoceroses, but Prof.
Owen showed that, anatomically, they possessed marked affinities with
the sloths. The klipdas or dasse (_Hyrax capensis_) is infested by a
tapeworm, of which hitherto the proglottides only appear to have been
seen (_Tænia hyracis_, Pallas). Under the name of _Cœnurus serialis_ a
larval cestode has been described by Gervais, the same parasite being
called _Arhynchotænia critica_ by Pagenstecher (“Zur Naturgeschichte
der Cestoden,” in ‘Sieb. u. Köll. Zeitschrift’). A variety of
nematodes have also been observed in the Cape hyrax. Of these, the
so-called _Physaloptera spirula_ is classed as doubtful by Molin and
Diesing. Hemprich and Ehrenberg furnished brief descriptions of four
other nematodes. Two of these worms were placed in the genus Oxyuris
(_O. pugio_ and _O. flavellum_), and the other two in the new genus
Crossophorus, which they formed for their reception (_C. collaris_ and
_C. tentaculatus_). The whole of these nematoids were obtained either
from the cæcum or large intestine.

An able article in the ‘Natural History Review’ for July 1865,
attributed to Professor Huxley, expressed very clearly the popular
notion as to the great danger of the flesh of swine considered as a
source of human parasites. No doubt the filthy pachyderms in question
(_Suidæ_) are much infested by helminths, some of which gain access to
man, but swine are neither attacked by a greater variety of entozoa
than other domesticated animals, nor are they so frequently a source of
human tapeworms as cattle. In the article above quoted the following
passage occurs:--“Of all animals, feral or domestic, the common pig is
beyond all doubt the most fertile source of human entozoa; at least, of
important parasites, _Trichina spiralis_ and the tapeworm would, there
is good reason to believe, cease to infest us, did not this favorite
quadruped act the part of a communicating medium.” This paragraph was
evidently written under the impression that “the tapeworm” most commonly
found in man was derived from the hog. So far back as 1864 I showed that
this was an entire mistake.

[Illustration: FIG. 66.--Head and neck of _Cysticercus_ from the Red
River hog. Magnified 60 diameters. Original.]

Flukes are rare in swine; nevertheless, _Fasciola hepatica_ and
_Distoma lanceolatum_ are occasionally present in the domestic hog,
and the peccaries (_Dicotyles_) are infested by an Amphistome (_A.
giganteum_). This large species, 3/4″ in length, formed the basis
of an admirable account of the anatomy of this genus of worms which
the learned Vienna helminthologist, Diesing, wrote before he was
deprived of his eyesight. The merits of that respected systematist’s
investigations have, I think, been much underrated, in consequence, no
doubt, of the artificial character of his system of classification.
For all that, his writings remain invaluable. Turning to the cestodes
of swine, there is not, so far as I am aware, any evidence of the
occurrence of sexually-mature tapeworms either in the hog or its allies;
but the frequency of larval cestodes, known as measles (_Cysticercus
telæ cellulosæ_), was well known to the early Jewish writers. In the
first part of this work I devoted as much space as I could spare to
the consideration of Cysticerci in general, and the pork-measle in
particular; but an exhaustive knowledge of the subject in relation
to hygiene can only be acquired by consulting the principal original
memoirs (quoted in the Bibliographies Nos. 13 and 14). In a Westphalian
ham, part of which was sent to me for examination, I calculated that
each pound of the flesh must have contained upwards of 600 Cysticerci.
I was informed by the donor, Dr Prior, that in spite of the disgusting
state of the meat much of it had been eaten by the well-to-do family
who purchased the ham. Cysticerci occasionally occupy the brain of the
pig in considerable numbers. Florman recorded a case of this kind where
their presence gave rise to vertigo in all respects resembling the gid
ordinarily produced by _Cœnurus_ in the sheep. As regards the larger
cestode larvæ, _Cysticercus tenuicollis_ and _Echinococcus veterinorum_
are of frequent occurrence. One not unfrequently encounters the former
in the mesentery, whilst the liver of the hog is sometimes so crowded
with hydatids that scarcely any of the glandular substance of the organ
remains visible. It is surprising how little the infested bearers
appear to be inconvenienced in such cases. In the winter of 1859, and
in the autumn of 1860, I found large cystic entozoa in an African
Wart-hog and in a Red River hog. These animals had died at the London
Zoological Society’s Menagerie; and as the worms appeared to me at the
time to be quite distinct from the ordinary slender-necked hydatid, they
were named, respectively, _Cysticercus phacochæri æthiopici_ and _C.
potamochæri penicillati_. The solitary example from the wart-hog was
found in a cyst near the colon; whilst of the five large bladder-worms
obtained from the Red River hog, one infested the liver and the other
four were lodged in the folds of the mesentery. The caudal vesicle of
the worm from the wart-hog measured 3-1/2″ in diameter, the vesicle of
the other bladder-worm being much longer. A reference to the original
figures will show that these forms are distinct. Swine are largely
infested by nematodes. The best-known form is _Ascaris lumbricoides_,
which Dujardin regarded as distinct (_A. suilla_). The hitherto disputed
identity of this worm with the human lumbricoid being no longer
questionable, the importance of the entozoon in relation to lumbricoid
endemics must at once be obvious; I have already, however, dwelt upon
this subject when treating of the human parasites. In like manner, the
subject of the flesh-worm disease, which is due to _Trichina spiralis_,
cannot be discussed in this place, as I have fully entered upon it
in connection with trichinosis in the human subject. What may be the
nature of the small threadworms found by Leidy in the extensor muscles
of the hog I cannot say, but Diesing inferred that they might represent
a distinct species (_Trichina affinis_). As regards the allied genus
_Trichocephalus_, the common species infesting swine (_T. crenatus_),
appears to be rarely absent. It not only infests the common domestic and
wild hog, but the peccaries and wart-hogs. These entozoa are probably
harmless to their bearers. In reference to them Krabbe says:--“When
the eggs are expelled with the excrement and pass into water, then the
embryos, after several months’ furlough, and there undergoing further
development, are transferred to the swine’s intestinal canal.” If I
rightly understand the paragraph (‘Husdyrenes Indvoldsorme,’ p. 28),
Krabbe states that the embryos are still within their egg-coverings when
infection takes place. The maw-worm of the hog is known as _Spiroptera
strongylina_. It was described and figured by Gurlt. The males measure
1/2″ and the females 3/4″ in length. Specimens of this worm were
supposed to have been found by Natterer in _Dicotyles albirostris_; but
it seems that the worms in question represent a distinct species, if
not an altogether new genus. In the year 1864 Professor Simonds placed
in my hands a very singular nematode, to which I gave the binomial
term _Simondsia paradoxa_. Numerous examples of this worm were found
by Prof. Simonds occupying cysts within the walls of the stomach of a
hog which had died at the London Zoological Society’s Menagerie. In my
introductory treatise I wrote of it as follows:--“The worm in question
has been regarded by Mr Simonds as a species of _Strongylus_, but I am
inclined to think that its affinities will place it nearer to the genus
_Spiroptera_. At present I have only examined the female, which is
characterised by the possession of a multitude of large tentacle-like
appendages surrounding the neck. These processes, by their aspect,
remind one of the so-called branchial projections on the back of
_Eolis_, but in this worm I believe them to be special folds formed for
the lodgment of unusually developed uterine organs. The female worm is
about 3/4″ in length.”

In the interval that has elapsed I have been unable to supply further
particulars, and unfortunately the original drawings of the worm
have been lost. The habits of the parasite remind us of _Spiroptera
megastoma_ infesting the walls of the stomach of the horse. Not
improbably this singular entozoon may turn out to be identical with
Molin’s _Spiroptera sexalata_, and if so, it may correspond with
_Spiroptera strongylina_. However, Diesing afterwards recognising, as
I had done, the desirability of separating this last-named worm from
the Spiropteræ proper, formed for it his new genus _Physocephalus_. He
then called the worm _Physocephalus sexalatus_. If, as is probable,
my _Simondsia_ and Diesing’s _Physocephalus_ are identical, the
species found by Simonds ought to be recognised by the generic title
which Diesing proposed. His genus was established about four years
before I described my _Simondsia_. Diesing was evidently led up to
the recognition of the generic distinction of the worm by Molin’s
examination and description of the worm. As, in my original account
of the worm found by Simonds, I spoke of numerous appendages to the
neck, it is evident that further investigation is necessary to clear
up the question of identity. According to Molin and Diesing the male
_Spiroptera sexalata_ measures rather beyond 1/4″ and the female beyond
1/2″ in length. Neither Diesing nor Molin speak of Natterer’s worms as
being found encysted. In fact they were free. Molin simply remarks:--“Io
ne esaminai in oltre 6 esemplari maschi e 77 femine raccolti in parte
dal muco che revestiva le pareti dello stomaco, ed in parte dal pasto
contenuto nello stesso organo di un _Dicotyles albirostris_ femina ai 24
Aprile, 1826.” After all that has been said it may be that my _Simondsia
paradoxa_ and Diesing’s _Physocephalus sexalata_ are quite distinct,
and that like the large- and small-mouthed maw-worms of the horse
(_Spiroptera megastoma_ and _S. microstoma_) they play a corresponding
rôle. Before very long I hope to set this question definitively at rest.

Passing to the strongyloid nematodes one of the most remarkable and
important species is _Stephanurus dentatus_. In the ‘Annalen des Wiener
Museums’ for 1839 (s. 232) this worm was first described by Diesing,
who employed the generic title as expressive of the crown-like figure
of the tail of the male worm. Diesing wrote as follows:--“At Barra do
Rio Negro, on the 24th of March, 1834, Natterer discovered this peculiar
genus of worms occurring singly or several together in capsules situated
amongst the layers of fat in a Chinese race of _Sus scrofa domestica_.
The males measure from ten to thirteen lines long, the females from
fifteen to eighteen lines, the former being scarcely a line in breadth
at the middle of the body, whilst the latter are almost a line and
a half in thickness. The curved body thickens towards the tail, is
transversely annulated, and viewed with a penetrating lens is seen to be
furnished with integumentary pores. The oral aperture opens widely. It
is almost circular, and is supplied with six teeth at the margin. Two of
these standing opposed to one another are larger and stronger than the
rest. The tail of the male, when spread out evenly, is surrounded by a
coronet of five lancet-shaped flaps; the combined flaps being connected
together from base to apex by means of a delicate transparent membrane.
The single spiculum situated at the extreme end of the tail projects
slightly forward and is surrounded by three skittle-shaped bodies. The
tail of the female is curved upon itself, rounded off, and drawn out at
the extreme end into a straight beak-shaped point; whilst to both sides
of the stumpy caudal extremity of the body short vesicular prominences
are attached. The female reproductive outlet occurs at the commencement
of the second half of the body. Thus, judging by its external characters
this genus is most closely allied to _Strongylus_.” In reproducing
Diesing’s description I have here rendered the translation somewhat more
freely than in my previous record of the discovery given in ‘Nature’
(1871). The original description is supplemented by a brief account of
the internal anatomy of the worm.

So far as I am aware no subsequent notice of this entozoon appeared
until the year 1858, when Dr J. C. White gave some account of a “find”
made in the United States. This re-discovery was reported in the sixth
volume of the ‘Proceedings of the Boston Natural History Society.’ Dr
White says:--“The worms were found in the leaf-yard of an apparently
healthy hog, in the adipose tissue near the kidney. They occupied a
space of the same about the size of a man’s fist and had burrowed
through the mass in every direction, forming canals three or four
millimètres in diameter, which terminated in cysts. On cutting open
these cavities, which did not communicate with each other, they were
found filled with pus, and in each were two worms, male and female.” Dr
White expresses his opinion that the worms gained access to the tissues
“by boring through the circulatory system while in the embryonic
condition.” I think that Dr White deserves great credit for his correct
diagnosis of the species, and all the more so because he was evidently
not acquainted with Diesing’s original memoir. He expressly speaks
of the “scanty descriptions” hitherto given of the worm. As Dr White
had accurately determined the species in the presence of an American
Scientific Society, it is remarkable that neither Verrill nor Fletcher
should have identified the worm.

On the 10th of January, 1871, I received a letter from Prof. W. B.
Fletcher, of Indianapolis, Indiana, U.S.A., and in it he announced that
he had “found a worm” infesting the hog. The parasite was so abundant
in swine that he obtained it in “nine out of ten hogs” which he had
examined. Dr Fletcher sent me specimens of the worm for description
and identification, when I at once recognised them as examples of
Diesing’s _Stephanurus dentatus_. As Dr Fletcher’s first communication
to myself was undated I do not know precisely when he first encountered
the worm, but it was in 1870. In that same year Prof. Verrill received
specimens of the worm. He says that they were received from Dr J. C.
White. Failing to identify the parasites as _Stephanuri_, Verrill
(making no allusion to the ‘Proceedings of the Boston Society’) not
unnaturally supposed he had to deal with an entozoon that was new to
science. Accordingly he immediately described and figured the worm
under the combined title of _Sclerostoma pinguicola_. If these data
are correctly given, the re-discovery of the worm in America was due
to Dr J. C. White; its identity with _Stephanurus_ being subsequently
acknowledged by Diesing, and afterwards, quite independently, by
myself. I gather this partly from Diesing’s ‘Kleine helminthologische
Mittheilungen’ (s. 281), published as a supplement to his ‘Revision
der Nematoden’ (1860-61). Until quite recently Diesing’s recognition
of the identity of White’s parasites with Stephanuri was unknown
in America. My conclusions arose from an examination of the actual
specimens, whereas Diesing was entirely guided by White’s description.
In this connection, moreover, a still more interesting re-discovery
remained to be recorded. The original announcement which I made in
the ‘British Medical Journal’ for January 14th, 1871, was followed
by another in the same periodical for September, 1871. As stated in
my second letter and repeated in my notice of Krabbe’s memoir on
“Parasites” (‘London Medical Record,’ April 2, 1873), the President
of the London Microscopical Society (through Mr Slack, who was at
that time the secretary) forwarded to me a box of microscopic slides
received by the Society from Australia. The slides displayed parasites
of various kinds. Having been requested to identify the parasites I had
the good fortune to recognise amongst them characteristic examples of
_Stephanurus dentatus_. Thus was first made known the fact that this
singular genus was not confined in its geographical distribution to the
two American continents, but that it extended to Australia. The order of
the principal “finds” and descriptions may therefore be thus restated.
Natterer discovered the worm in Brazil in 1834. Diesing described it in
1839. Dr J. C. White re-discovered and identified the worm in 1858. It
was subsequently found by Dr N. Cressy and by Dr Fletcher. These three
observers all encountered the parasite in the United States (1858-70).
Prof. Verrill re-described the worm as new to science in September,
1870. Diesing confirmed White’s diagnosis in 1860. I identified the worm
from Fletcher’s “find” in 1871. Dr Morris supposed he had discovered
a new entozoon in Australia in July, 1871. The Australian worms were
identified by me as examples of _Stephanurus dentatus_ in October, 1871.

The importance of _Stephanurus_ in relation to porcine epizoöty and the
supply of animal food cannot be ignored. As remarked in my communication
to ‘Nature,’ it must be quite obvious that so large a parasite, when
present in the hog in any considerable numbers, would give rise to
serious disease, even if it were not productive of fatal results to
the bearer. In one of his numerous communications to myself, Prof. W.
B. Fletcher writes as follows:--“It is my opinion that this parasite
is the cause, in some way, of the hog cholera, which has created such
sad havoc within the past ten years over the pork-producing parts of
America. One farmer told me, a few days ago, that within a month his
loss alone from this cause was over one hundred head; and sometimes,
in one neighbourhood, in a few days’ time, thousands have perished,
although this season is not a cholera year, as our farmers say. I
advised one farmer to burn or bury the dead animals, but he informed
me that he believed that fewer hogs die of the disease after eating
the