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Title: The Kingdom of Man
Author: Lankester, Sir E. Ray (Edwin Ray)
Language: English
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[Illustration: Cranial Dome of _Pithecanthropus erectus_ from river
gravel in Java.
Skull of a Greek from an ancient Cemetery.]
THE KINGDOM OF MAN
by
E. RAY LANKESTER
M.A. D.Sc. LL.D. F.R.S.
Honorary Fellow of Exeter College, Oxford; Correspondent
of the Institute of France; Emeritus Professor
of University College, London; President
of the British Association for the
Advancement of Science
Director of the Natural History Departments of the
British Museum
London
Archibald Constable & Co Ltd
10 Orange Street, Leicester Square
1907
* * * * * *
EXTINCT ANIMALS
BY
Prof. E. RAY LANKESTER, F.R.S.
With a Portrait of the Author, and 218 other Illustrations
_Demy 8vo._ _Price 7s. 6d. net_
DESCRIPTIVE NOTE.
The author gives us here a peep at the wonderful history of the
kinds of animals which no longer exist on the surface of the globe
in a living state, though once they flourished and held their own.
Young and old readers will alike enjoy Prof. Lankester’s interesting
narrative of these strange creatures, some of which became extinct
millions of years ago, others within our own memory. The author’s
account of the finding of their extant remains, their probable habits
and functions of life, and their places in the world’s long history,
is illustrated profusely from point to point, adding greatly to the
entertainment of the story.
_=Nature=_: “ ... We give the book a hearty welcome, feeling sure
that its perusal will draw many young recruits to the army of
naturalists, and many readers to its pages.”
_=The Times=_: “There has been published no book on this
subject combining so successfully the virtues of accuracy and
attractiveness.... Dr. Lankester’s methods as an expositor are
well known, but they have never been more pleasantly exemplified
than in the present book.”
_=The Athenæum=_: “Examples of Extinct Animals and their living
representatives Professor Lankester has described with a masterly
hand in these present pages.”
LONDON
ARCHIBALD CONSTABLE & CO LTD
10 ORANGE STREET, LEICESTER SQUARE
* * * * * *
Eyre & Spottiswoode, H.M. Printers, London
DESCRIPTION OF THE FRONTISPIECE
The upper figure is from a cast of the celebrated specimen found in
a river gravel in Java, probably of as great age as the palæolithic
gravels of Europe. Though rightly to be regarded as a ‘man’--the
creature which possessed this skull has been given the name
‘_Pithecanthropus_.’ The shape of the cranial dome differs from
that of a well-developed European human skull (shewn in the lower
photograph, that of a Greek skull) in the same features as do the
very ancient prehistoric skulls from the Belgian caves of Spey,
and from the Neanderthal of the Rhineland. These differences are,
however, measurably greater in the Javanese skull.
The three great features of difference are: (1) the great size of the
eye-brow ridges (the part below and in front of A in the figures) in
the Java skull; (2) the much greater relative height of the middle
and back part of the cranial dome (lines _e_ and _f_) in the Greek
skull; (3) the much greater prominence in the Greek skull of the
front part of the cranial dome--the prefrontal area or frontal ‘boss’
(the part in front of the line A C, the depth of which is shewn by
the line _d_).
The parts of the cranial cavity thus obviously more capacious in
the Greek skull are precisely those which are small in the Apes and
overlie those convolutions of the brain which have been specially
developed in Man as compared with the highest Apes.
The line A B in both the figures is the ophryo-tentorial line. It is
drawn from the ophryon (the mid-point in the line drawn across the
narrowest part of the frontal bone just above the eye-brow ridges),
which corresponds externally to the most anterior limit of the brain,
to the extra-tentorial point (between the occipital ridges) and is
practically the base line of the cerebrum. The lines _e_ and _f_ are
perpendiculars on this base line, the first half-way between A and B,
the second half-way between the first and the extra-tentorial point.
C is the point known to craniologists as ‘bregma,’ the meeting point
of the frontal and the two parietal bones.
The line A C is drawn as a straight line joining A and C--but if the
skull is accurately posed it corresponds to the edge of the plane at
right angles to the sagittal plane of the skull--which traverses both
bregma (C) and ophryon (A)--and where it ‘cuts’ the skull marks off
the prefrontal area or boss. (See for the full-face view of this area
in the two skulls--Figs. 1 and 2.) The line _d_ is a perpendicular
let fall from the point of greatest prominence of the prefrontal area
on to the prefrontal plane. It indicates the depth of the prefrontal
cerebral region. Drawn on both sides on the surface of the bone and
looked at from in front (the white dotted line in Figs. 1 and 2) it
gives the maximum breadth of the prefrontal area.
By dividing the ophryo-tentorial line into 100 units, and using those
units as measures, the depths of the brain cavity in the regions
plumbed by the lines _d_, _e_, and _f_, can be expressed numerically
and their differences in a series of skulls stated in percentage of
the ophryo-tentorial length.
CONTENTS
PAGE
CHAPTER I.--NATURE’S INSURGENT SON 1
CHAPTER II.--THE ADVANCE OF SCIENCE, 1881-1906 66
CHAPTER III.--NATURE’S REVENGES: THE SLEEPING SICKNESS 159
LIST OF ILLUSTRATIONS
FRONTISPIECE:--Profile views of the Cranial Dome of
_Pithecanthropus erectus_, the ape-like man from
an ancient river gravel in Java, and of a Greek skull.
FIG. 1.--Frontal view of the Cranial Dome of
_Pithecanthropus_ 16
FIG. 2.--Frontal view of the same Greek skull as that shown
in the frontispiece 16
FIG. 3.--Eoliths, of ‘borer’ shape, from Ightham, Kent 18
FIG. 4.--Eoliths of trinacrial shape, from Ightham, Kent 20
FIG. 5.--Brain casts of four large Mammals 23
FIG. 6.--_Spironema pallidum_, the microbe of Syphilis
discovered by Fritz Schaudinn 37
FIG. 7.--The Canals in Mars 43
FIG. 8.--The Canals in Mars 44
FIG. 9.--Becquerel’s shadow-print obtained by rays from
Uranium Salt 73
FIG. 10.--Diagrams of the visible lines of the Spectrum
given by incandescent Helium and Radium 76
FIG. 11.--The transformation of Radium Emanation into
Helium (spectra) 83
FIG. 12.--Dry-plate photograph of a Nebula and surrounding
stars 90
FIG. 13.--The Freshwater Jelly fish, _Limnocodium_ 97
FIG. 14.--Polyp of _Limnocodium_ 97
FIG. 15.--Sense-organ of _Limnocodium_ 97
FIG. 16.--The Freshwater Jelly-fish of Lake Tanganyika 98
FIG. 17.--Sir Harry Johnston’s specimen of the Okapi 99
FIG. 18.--Bandoliers cut from the striped skin of the Okapi 99
FIG. 19.--Skull of the horned male of the Okapi 100
FIG. 20.--The metamorphosis of the young of the common Eel 101
FIG. 21.--A unicellular parasite of the common Octopus,
producing spermatozoa 102
FIG. 22.--The _Coccidium_, a microscopic parasite of
the Rabbit, producing spermatozoa 102
FIG. 23.--Spermatozoa of a unicellular parasite inhabiting
a Centipede 103
FIG. 24.--The motile fertilizing elements (antherozoids or
spermatozoa) of a peculiar cone-bearing tree, the
_Cycas revoluta_ 104
FIG. 25.--The gigantic extinct Reptile, _Triceratops_ 106
FIG. 26.--A large carnivorous Reptile from the Triassic
rocks of North Russia 107
FIG. 27.--The curious fish _Drepanaspis_, from the
Old Red Sandstone of Germany 107
FIG. 28.--The oldest Fossil Fish known 108
FIG. 29.--The skull and lower jaw of the ancestral Elephant,
_Palæomastodon_, from Egypt 109
FIG. 30.--The latest discovered skull of _Palæomastodon_ 110
FIG. 31.--Skulls of _Meritherium_, an Elephant ancestor,
from the Upper Eocene of Egypt 111
FIG. 32.--The nodules on the roots of bean-plants and the
nitrogen-fixing microbe, _Bacillus radicola_,
which produces them 114
FIG. 33.--The continuity of the protoplasm of vegetable
cells 116
FIG. 34.--Diagram of the structures present in a typical
organic ‘cell’ 117
FIG. 35.--The Number of the Chromosomes 119
FIG. 36.--The Number of the Chromosomes 120
FIGS. 37 to 42.--Phagocytes engulphing disease germs--drawn
by Metschnikoff 136-7
FIG. 43.--A Phagocyte containing three Spirilla, the germs
of relapsing fever, which it has engulphed 137
FIG. 44.--The life-history of the Malaria Parasite 142
FIG. 45.--The first blood-cell parasite described, the
_Lankesterella_ of Frog’s blood 144
FIG. 46.--Various kinds of Trypanosomes 145
FIG. 47.--The Laboratory of the Marine Biological Association
on the Citadel Hill, Plymouth 155
FIG. 48.--The Tsetze fly, _Glossina morsitans_ 172
FIG. 49.--The Trypanosome of Frog’s blood 173
FIG. 50.--The Trypanosome which causes the Sleeping
Sickness 176
FIG. 51.--The Trypanosome of the disease called “Dourine” 177
FIGS. 52 to 56.--Stages in the growth and multiplication of
a Trypanosome which lives for part of its life in
the blood of the little owl, _Athene noctua_,
and for the other part in the gut of the common
Gnat (_Culex_) 180-3
PREFACE
_This little volume is founded on three discourses which I have
slightly modified for the present purpose, and have endeavoured
to render interesting by the introduction of illustrative process
blocks, which are described sufficiently fully to form a large
extension of the original text._
_The first, entitled ‘Nature’s Insurgent Son,’ formed, under another
title, the Romanes lecture at Oxford in 1905. Its object is to
exhibit in brief the ‘Kingdom of Man,’ to shew that there is undue
neglect in the taking over of that possession by mankind, and to urge
upon our Universities the duty of acting the leading part in removing
that neglect._
_The second is an account, which served as the presidential address
to the British Association at York in 1906, of the progress made in
the last quarter of a century towards the assumption of his kingship
by slowly-moving Man._
_The third, reprinted from the_ Quarterly Review, _is a more detailed
account of recent attempts to deal with a terrible disease--the
Sleeping Sickness of tropical Africa--and furnishes an example of
one of the innumerable directions in which Man brings down disaster
on his head by resisting the old rule of selection of the fit and
destruction of the unfit, and is painfully forced to the conclusion
that knowledge of Nature must be sought and control of her processes
eventually obtained. I am glad to be able to state that as a result
of the representations of the Tropical Diseases Committee of the
Royal Society, and, as I am told, in some measure in consequence of
the explanation of the state of things given in this essay, funds
have been provided by the Colonial Office for the support of a
professorship of Protozoology in the University of London, to which
Mr. E. A. Minchin has been appointed. It is recognized that the only
way in which we can hope to deal effectually with such diseases as
the Sleeping Sickness is by a greatly increased knowledge of the
nature and life-history of the parasitic Protozoa which produce those
diseases._
_I have to thank Mr. John Murray for permission to reprint the
article on Sleeping Sickness, and I am also greatly indebted to
scientific colleagues for assistance in the survey of progress given
in the second discourse. Amongst these I desire especially to mention
Mr. Frederick Soddy, F.R.S., Prof. H. H. Turner, F.R.S., Prof. Sydney
Vines, F.R.S., Mr. MacDougal of Oxford, and Prof. Sherrington, F.R.S.
To Mr. Perceval Lowell I owe my thanks for permission to copy two of
his drawings of Mars, and to the Royal Astronomical Society for the
loan of the star-picture on p. 90._
E. RAY LANKESTER,
_January, 1907_.
ERRATUM.
Page 98: first line of description beneath Fig. 16., _for_
Limnocodium _read_ Limnocnida.
THE KINGDOM OF MAN
CHAPTER I
_NATURE’S INSURGENT SON_
1. THE OUTLOOK.
It has become more and more a matter of conviction to me--and I
believe that I share that conviction with a large body of fellow
students both in this country and other civilized states--that
the time has arrived when the true relation of Nature to Man has
been so clearly ascertained that it should be more generally known
than is at present the case, and that this knowledge should form
far more largely than it does at this moment, the object of human
activity and endeavour,--that it should be, in fact, the guide of
state-government, the trusted basis of the development of human
communities. That it is not so already, that men should still allow
their energies to run in other directions, appears to some of us a
thing so monstrous, so injurious to the prosperity of our fellow
men, that we must do what lies within our power to draw attention
to the conditions and circumstances which attend this neglect, the
evils arising from it, and the benefits which must follow from its
abatement.
2. THE WORD ‘NATURE.’
The signification attached to the word ‘Nature’ is by no means the
same at the present day as it has been in the past: as commonly
used it is a word of varied meanings and limitations, so that
misconception and confusion is liable to be associated with it. By
the professed student of modern sciences it is usually understood
as a name for the entire mechanism of the universe, the kosmos in
all its parts; and it is in this sense that I use it. But many still
identify ‘Nature’ with a limited portion of that great system, and
even retain for it a special application to the animals and plants
of this earth and their immediate surroundings. Thus we have the
term ‘natural history’ and the French term ‘les sciences naturelles’
limited to the study of the more immediate and concrete forms of
animals, plants, and crystals. There is some justification for
separating the conception of Nature as specially concerned in the
production and maintenance of living things from that larger Nature
which embraces, together with this small but deeply significant area,
the whole expanse of the heavens in the one direction and Man himself
in the other. Giordano Bruno, who a little more than 300 years ago
visited Oxford and expounded his views, was perhaps the first to
perceive and teach the unity of this greater Nature, anticipating
thus in his prophetic vision the conclusion which we now accept as
the result of an accumulated mass of evidence. Shakespeare came into
touch with Bruno’s conception, and has contrasted the more limited
and a larger (though not the largest) view of Nature in the words of
Perdita and Polyxenes. Says Perdita:--
‘ ... the fairest flowers o’ the season
Are our carnations, and streak’d gillyvors,
Which some call Nature’s bastards; of that kind
Our rustic garden’s barren; and I care not
To get slips of them.... For I have heard it said,
There is an art which, in their piedness, shares
With great creating nature.’
To which Polyxenes replies:--
‘Say there be--
Yet nature is made better by no mean,
But nature makes that mean: so, over that art,
Which, you say, adds to nature, is an art
That nature makes. You see, sweet maid, we marry
A gentle scion to the wildest stock;
And make conceive a bark of baser kind
By bud of nobler race; this is an art
Which does mend nature,--change it, rather: but
The art itself is nature.’
The larger proportion of so-called educated people even at the
present day have not got beyond Perdita’s view of Nature. They regard
the territory of Nature as a limited one, the play-ground or sport
of all sorts of non-natural demons and fairies, spirits and occult
agencies. Apart from any definite scheme or conception of these
operations, they personify Nature and attribute a variety of virtues
and tendencies to her for which there is no justification. We are
told, according to the fancy of the speaker, that such a course is in
accordance with Nature; that another course is contrary to Nature; we
are urged to return to Nature and we are also urged to resist Nature.
We hear that Nature will find a remedy for every ill, that Nature
is just, that Nature is cruel, that Nature is sweet and our loving
mother. On the one hand Man is regarded as outside of and opposed to
Nature, and his dealings are contrasted favourably or unfavourably
with those of Nature. On the other hand we are informed that Man
must after all submit to Nature and that it is useless to oppose
her. These contradictory views are in fact fragments of various
systems of philosophy of various ages in which the word ‘Nature’ has
been assigned equally various limitations and extensions. Without
attempting to discuss the history and justification of these
different uses of the word Nature, I think that I may here use the
word Nature as indicating the entire kosmos of which this cooling
globe with all upon it is a portion.
3. NATURE-SEARCHERS.
The discovery of regular processes, of expected effects following
upon specified antecedents, of constant properties and qualities in
the material around him, has from the earliest recorded times been a
chief occupation of Man and has led to the attainment by Man of an
extraordinarily complex control of the conditions in which his life
is carried on. But it was not until Bruno’s conception of the unity
of terrestrial nature with that of the kosmos had commended itself
that a deliberate and determined investigation of natural processes,
with a view to their more complete apprehension, was instituted.
One of the earliest and most active steps in this direction was the
foundation, less than 250 years ago, of the Royal Society of London
for the Promotion of Natural Knowledge, by a body of students who
had organized their conferences and inquiries whilst resident in
Oxford.[1]
All over Western Europe such associations or academies for the
building up of the New Philosophy (as it was called here) came
into existence. It is a fact which is strangely overlooked at the
present day, when the assumption is made that the acquirement of
a knowledge of Greek grammar is the traditional and immemorial
occupation of Oxford students--that until the modern days of the
eighteenth century (‘modern’ in the history of Oxford) Greek was
less known in Oxford than Hebrew is at present, and that the study
of Nature--Nature-knowledge and Nature-control--was the appropriate
occupation of her learned men. It is indeed a fact that the very
peculiar classical education at present insisted on in Oxford, and
imposed by her on the public schools of the country, is a modern
innovation, an unintentional and, in a biological sense, ‘morbid’
outgrowth of that ‘Humanism’ to which a familiarity with the dead
languages was, but is no longer, the pathway.
4. THE DOCTRINE OF EVOLUTION.
What is sometimes called the scientific movement, but may be
more appropriately described as the Nature-searching movement,
rapidly attained an immense development. In the latter half of
the last century this culminated in so complete a knowledge of the
movements of the heavenly bodies, their chemical nature and physical
condition--so detailed a determination of the history of the crust
of this earth and of the living things upon it, of the chemical and
physical processes which go on in Man and other living things, and
of the structure of Man as compared with the animals most like him,
and of the enormous length of time during which Man has existed on
the earth--that it became possible to establish a general doctrine
of the evolution of the kosmos, with more special detail in regard
to the history of this earth and the development of Man from a lower
animal ancestry. Animals were, in their turn, shown to have developed
from simplest living matter, and this from less highly elaborated
compounds of chemical ‘elements’ differentiated at a still earlier
stage of evolution. There is, it may be said without exaggeration,
no school or body of thinkers at the present day who are acquainted
with the facts now ascertained, which denies the orderly evolution
of the kosmos by the regular operation of a more or less completely
ascertained series of properties resident in the material of which
it consists.[2] The process of evolution--the interaction of these
ascertainable, if not fully ascertained properties--has led (it is
held), in the case of the cooling cinder which we call the earth--by
an inevitable and predestined course--to the formation of that which
we call living matter and eventually of Man himself. From this
process all disorderly or arbitrary interferences must, it seems, be
excluded. The old fancies as to presiding demons or fairies--which
it was imagined had for their business to interrupt the supposed
feeble and limited efforts of Nature, as yet unexplored and
unappreciated--have passed out of mind. The consensus is complete:
Man is held to be a part of Nature, a product of the definite and
orderly evolution which is universal; a being resulting from and
driven by the one great nexus of mechanism which we call Nature. He
stands alone, face to face with that relentless mechanism. It is his
destiny to understand and to control it.
5. UNWARRANTED INFERENCES FROM THE EVOLUTION OF MAN.
There are not wanting those who, accepting this conclusion, seek to
belittle Man and endeavour to represent that the veil is lifted, that
all is ‘explained’ obvious, commonplace, and mean in regard to the
significance of life and of Man, because it has become clear that
the kosmic process has brought them forth in due order. There are
others who rightly perceive that life is no common property of our
cooling matter, but unique and exceptional, and that Man stands apart
from and above all natural products, whether animate or inanimate.
Some of these thinkers appear to accept the conclusion that if life
and Man are regarded as products of the kosmic process--that is, of
Nature--‘life’ and ‘Man’ lose so much in importance and significance
that dire consequences must follow to Man’s conception of his dignity
and to the essential features of his systems of conduct and social
organization. Accordingly they cling to the belief that living matter
and Man have not proceeded from an orderly evolution of Nature, but
are ‘super’ natural. It is found on the other hand, by many who have
considered these speculations, and hold no less explicitly than do
the ‘supernaturalists’ that life is a momentous and peculiar feature
of our earth’s surface and Man the isolated and unparalleled ‘piece
of work,’ ‘the beauty of the world,’ ‘the paragon of animals’--it
is found by many such, I say, that nothing is gained in regard to
our conception of Man’s nobility and significance by supposing that
he and the living matter which has given rise to him, are not the
outcome of that system of orderly process which we call Nature.
There is one consideration in regard to this matter which, it seems,
is often overlooked and should be emphasized. It is sometimes--and
perhaps with a sufficient excuse in a want of acquaintance with
Nature--held by those who oppose the conclusion that Man has been
evolved by natural processes, that the products of Nature are
arbitrary, haphazard, and due to chance, and that Man cannot be
conceived of as originating by chance. This notion of ‘chance’ is a
misleading figment inherited by the modern world from days of blank
ignorance. The ‘Nature-searchers’ of to-day admit no such possibility
as ‘chance.’ It will be in the recollection of many here, that a
leading writer and investigator of the Victorian Era, the physicist
John Tyndall, pointed out in a celebrated address delivered at
Belfast that according to the conceptions of the mechanism of Nature
arrived at by modern science--the structure of that mechanism is such
that it would have been possible for a being of adequate intelligence
inspecting the gaseous nebula from which our planetary system has
evolved to have foreseen in that luminous vapour the Belfast audience
and the professor addressing it!
The fallacy that in given but unknown circumstances anything
whatever may occur in spite of the fact that some one thing has been
irrevocably arranged to occur, is a common one.[3] It is correct to
assume in the absence of any pertinent knowledge (if we are compelled
to estimate the probabilities) that one event is as likely as another
to occur; but nevertheless there is no ‘chance’ in the matter since
the event has been already determined, and might be predicted by
those possessing the knowledge which we lack. Thus then it appears
that the conclusion that Man is a part of Nature is by no means
equivalent to asserting that he has originated by ‘blind chance’; it
is in fact a specific assertion that he is the predestined outcome of
an orderly--and to a large extent ‘perceptible’--mechanism.[4]
6. NATURE’S MODE OF PRODUCING ORGANIC FORMS.
The general process by which the higher and more elaborate forms of
life, and eventually man himself, have been produced has been shown
by Darwin to depend upon two important properties of living matter
manifested in connexion with the multiplication of individuals.
Living matter has a special property of adding to its bulk by
taking up the chemical elements which it requires and building up
the food so taken as additional living matter. It further has the
power of separating from itself minute particles or germs which
feed and grow independently, and thus multiply their kind. It is
a fundamental character of this process of reproduction that the
detached or pullulated germ inherits or carries with it from its
parents the peculiarities of form and structure of its parent. This
is the property known as Heredity. It is most essentially modified
by another property--namely, that though eventually growing to be
closely like the parent, the germ (especially when it is formed, as
is usual, by the fusion of two germs from two separate parents) is
never identical in all respects with the parent. It shows Variation.
In virtue of Heredity, the new congenital variations shown by a new
generation are transmitted to their offspring when in due time they
pullulate or produce germs. Man has long been aware of this; and, by
selecting variations of beasts, birds, or plants agreeable or useful
to him, has intensified such variations and produced animals and
plants in many features very unlike those with which he started.
It was Darwin’s merit to show that a process of selection which he
called ‘Natural Selection’ must take place in the free untouched
conditions under which animals and plants exist, and have existed
for ages, on this globe. Both animals and plants produce germs, or
young, in excess--usually in vast excess. The world, the earth’s
surface, is practically full, that is to say, fully occupied. Only
one pair of young can grow up to take the place of the pair--male
and female--which have launched a dozen, or it may be as many as a
hundred thousand, young individuals on the world. The property of
Variation ensures that amongst this excess of young there are many
differences. Eventually those survive which are most fitted to the
special conditions under which this particular organism has to live.
The conditions may, and indeed in long lapses of time must, change,
and thus some variation not previously favoured will gain the day
and survive. The ‘struggle for existence’ of Darwin is the struggle
amongst all the superabundant young of a given species, in a given
area, to gain the necessary food, to escape voracious enemies, and
gain protection from excesses of heat, cold, moisture, and dryness.
One pair in the new generation--only one pair--survive for every
parental pair. Animal population does not increase: ‘Increase and
multiply’ has never been said by Nature to her lower creatures.
Locally, and from time to time, owing to exceptional changes, a
species may multiply here and decrease there; but it is important
to realize that the ‘struggle for existence’ in Nature--that is to
say, among the animals and plants of this earth untouched by man--is
a desperate one, however tranquil and peaceful the battlefield may
appear to us. The struggle for existence takes place, not as a clever
French writer[5] glibly informs his readers, between different
species, but between individuals of the same species, brothers and
sisters and cousins. The struggle between a beast of prey which
seeks to nourish itself and the buffalo which defends its life with
its horns is not ‘the struggle for existence’ so named by Darwin.
Moreover, the struggle among the members of a species in natural
conditions differs totally from the mere struggle for advancement or
wealth with which uneducated writers so frequently compare it. It
differs essentially in this--that in Nature’s struggle for existence,
death, immediate obliteration, is the fate of the vanquished, whilst
the only reward to the victors--few, very few, but rare and beautiful
in the fitness which has carried them to victory--is the permission
to reproduce their kind--to carry on by heredity to another
generation the specific qualities by which they triumphed.
It is not generally realized how severe is the pressure and
competition in Nature--not between different species, but between the
immature population of one and the same species, precisely because
they are of the same species and have exactly the same needs. From a
human point of view the pressure under which many wild things live
is awful in its severity and relentless tenacity. Not only are new
forms established by natural selection, but the old forms, when they
exactly fit the mould presented as it were for competitive filling,
are maintained by the same unremitting process. A distinctive quality
in the beauty of natural productions (in which man delights) is due
to the unobtrusive yet tremendous slaughter of the unfit which is
incessantly going on, and the absolute restriction of the privilege
of parentage to the happy few who attain to the standard described as
‘the fittest.’
7. THE LIMITED VARIETY OF NATURE’S PRODUCTS.
The process of development of an immense variety of animal and
vegetable forms has proceeded in this way through countless ages
of geologic time, but it must not be supposed that any and every
conceivable form and variety has been produced. There are only two
great diverging lines of descent from original living matter--only
the animals and the plants. And in each of these there are and have
been only a limited number of branches to the pedigree--some coming
off at a lower level, others at higher points when more elaborate
structure has been attained. It is easy to imagine groups of both
plants and animals with characters and structures which have never
existed and never will exist. The limitation of the whole process
in spite of its enormous duration in time, its gigantic output and
variety, is a striking and important fact. Linnaeus said, ‘There are
just as many species as in the beginning the Infinite Being created’;
and the modern naturalist can go no further than the paraphrase of
this, and must say, ‘There are and have been just so many and just
so few varieties of animal and vegetable structure on this earth as
it was possible for the physical and chemical contents of the still
molten globe to form up to the hour now reached.’
8. THE EMERGENCE OF MAN.
As to how and when man emerged from the terrestrial animal population
so strictly controlled and moulded by natural selection is a matter
upon which we gain further information year by year. There must be
many here who remember, as I do, the astounding and almost sudden
discovery some forty-five years ago of abundant and overwhelming
evidence that man had existed in Western Europe as a contemporary
of the mammoth and rhinoceros, the hyaena and the lion. The dispute
over the facts submitted to the scientific world by Boucher de
Perthes was violent and of short duration. The immense antiquity of
man was established and accepted on all sides just before Mr. Darwin
published his book on _The Origin of Species_. The palæolithic
implements, though not improbably made 150,000 years ago, do not, any
more than do the imperfect skulls occasionally found in association
with them, indicate a condition of the human race much more
monkey-like than is presented by existing savage races (see Figs.
1 and 2 and Frontispiece, and their explanations). The implements
themselves are manufactured with great skill and artistic feeling.
Within the last ten years much rougher flint implements, of peculiar
types, have been discovered in gravels which are 500 feet above the
level of the existing rivers (see Figs. 3 and 4). These “Eoliths”
of the South of England indicate a race of men of less-developed
skill than the makers of the Palæoliths, and carry the antiquity of
man at least as far back beyond the Palæoliths as these are from
the present day. We have as yet found no remains giving the direct
basis for conclusions on the subject; but judging by the analogy
(not by any means a conclusive method) furnished by the history of
other large animals now living alongside of man--such as the horse,
the rhinoceros, the tapir, the wolf, the hyaena, and the bear--it is
not improbable that it was in the remote period known as the lower
Miocene--remote even as compared with the gravels in which Eoliths
occur--that Natural Selection began to favour that increase in the
size of the brain of a large and not very powerful semi-erect ape
which eventuated, after some hundreds of thousands of years, in the
breeding-out of a being with a relatively enormous brain-case, a
skilful hand, and an inveterate tendency to throw stones, flourish
sticks, protect himself in caves, and in general to defeat aggression
and satisfy his natural appetites by the use of his wits rather than
by strength alone--in which, however, he was not deficient.
Probably this creature had nearly the full size of brain and every
other physical character of modern man, although he had not as yet
stumbled upon the art of making fire by friction, nor converted
his conventional grunts and groans, his screams, laughter, and
interjections into a language corresponding to (and thenceforth
developing) his power of thought.
[Illustration: FIG. 1.--_Pithecanthropus_ from Java
FIG. 2.--Greek Skull
Photographs of a front view of the two skulls shewn in profile
in the frontispiece, taken so as to shew the breadth of the
‘forehead’ or prefrontal area, which is seen to be very much
greater in the Greek skull (Fig. 2) than in the Javanese
_Pithecanthropus_ (Fig. 1). The prefrontal area is marked out
by a black dotted line, the outline of a plane (the prefrontal
plane) which is at right angles to the sagittal plane and passes
through the meeting point of the frontal with the two parietal
bones above; whilst below it passes through the median point
called ‘ophryon.’ The plane of the picture is parallel with this
prefrontal plane. The white dotted line gives the breadth of
the boss-like prefrontal area. It is identical in position with
the line _d_ in the side view of the same skulls given in the
frontispiece. The black dotted line is identical in position with
the line A C in those figures. The two specimens are equally
reduced in the photograph. (Original).]
[Illustration: FIG. 3.
Photographs of eight Eoliths of one and the same shape, namely,
with a chipped or worked tooth-like prominence, rendering the
flint fit for use as a ‘borer’--photographed of half the actual
size (linear measurement) from specimens found near Ightham,
Kent, in the high-level gravel--which form part of the Prestwich
collection in the Natural History Museum, Cromwell Road, London.
Many others of the same shape have been found in the same
locality. These and the trinacrial implements photographed in
Fig. 4 are far older than the oval and leaf-shaped ‘palæoliths’
of the low-lying gravels of the valleys of the Thames, Somme, and
other rivers. (Original).]
[Illustration: FIG. 4.
Photographs of six Eoliths of the ‘shoulder-of-mutton’ or
‘trinacrial’ type--from the same locality and collection as those
shewn in Fig. 3. The photographs are of half the length of the
actual specimens. A considerable number of worked flints of this
peculiar shape have been found in the same locality. Possibly
their shape enabled the primitive men who ‘chipped’ and used them
to attach them by thongs to a stick or club. The descriptive term
‘trinacrial’ is suggested by me for these flints in allusion to
the form of the island of Sicily which they resemble. (Original).]
9. THE ENLARGED BRAIN.
The leading feature in the development and separation of man from
amongst other animals is undoubtedly the relatively enormous size of
the brain in man, and the corresponding increase in its activities
and capacity. It is a very striking fact that it was not in the
ancestors of man alone that this increase in the size of the brain
took place at this same period, viz. the Miocene. The great mammals
such as the titanotherium, which represented the rhinoceros in early
Tertiary times, had a brain which was in proportion to the bulk of
the body, not more than one-eighth the volume of the brain of the
modern rhinoceros (see Fig. 5). Other great mammals of the earlier
Tertiary period were in the same case; and the ancestors of the
horse, which are better known than those of any other modern animal,
certainly had very much smaller brains in proportion to the size of
their bodies than has their descendant.
[Illustration: FIG. 5.
Four casts of the brain-cavities of a series of large Ungulate
Mammals in order to shew the relatively small size of the
cerebral hemispheres of the extinct creature from which A is
taken.
A is that of _Dinoceras_, a huge extinct Eocene mammal which was
as large as a Rhinoceros; B is that of Hippopotamus; C of Horse;
and D of Rhinoceros.]
We may well ask to what this sudden and marked increase in the size
of the brain in several lines of the animal pedigree is due. It
seems that the inborn hereditary nervous mechanism by which many
simple and necessary movements of the body are controlled and brought
into relation with the outer world acting upon the sense-organs,
can be carried in a relatively small bulk of brain-substance.
Fish, lizards, and crocodiles with their small brains carry on a
complex and effective life of relation with their surroundings.
It appears that the increased bulk of cerebral substance means
increased ‘educability’--an increased power of storing up individual
experience--which tends to take the place of the inherited mechanism
with which it is often in antagonism. The power of profiting by
individual experience, in fact educability, must in conditions of
close competition be, when other conditions are equal, an immense
advantage to its possessor. It seems that we have to imagine that the
adaptation of mammalian form to the various conditions of life had in
Miocene times reached a point when further alteration and elaboration
of the various types, which we know then existed, could lead to no
advantage. The variations presented for selection in the struggle for
existence presented no advantage--the ‘fittest’ had practically been
reached, and was destined to survive with little change. Assuming
such a relative lull in the development of mere mechanical form,
it is obvious that the opportunity for those individuals with the
most ‘educable’ brains to defeat their competitors would arise. No
marked improvement in the instrument being possible, the reward, the
triumph, the survival would fall to those who possessed most skill in
the use of the instrument. And in successive generations the bigger
and more educable brains would survive and mate, and thus bigger and
bigger brains be produced.
It would not be difficult (though not, perhaps, profitable) to
imagine the conditions which have favoured the continuation of this
process to a far greater length in the Simian line of the pedigree
than in other mammalian groups. The result is that the creature
called Man emerged with an educable brain of some five or six times
the bulk (in proportion to his size and weight) of that of any other
surviving Simian. Great as is this difference, it is one of the most
curious facts in the history of man’s development that the bulk of
his brain does not appear to have continued to increase in any very
marked degree since early Palæolithic times. The cranial capacity of
many savage races and of some of the most ancient human skulls is
only a little less than that of the average man of highly-civilised
race. The value of the mental activities in which primitive man
differs from the highest apes may be measured in some degree by
the difference in the size of the man’s and the ape’s brain; but
the difference in the size of the brain of Isaac Newton and an
Australian black-fellow is not in the remotest degree proportionate
to the difference in their mental qualities. Man, it would seem, at
a very remote period attained the extraordinary development of brain
which marked him off from the rest of the animal world, but has
ever since been developing the powers and qualities of this organ
without increasing its size, or materially altering in other bodily
features.[6]
10. THE PROGRESS OF MAN.
The origin of Man by the process of Natural Selection is one chapter
in man’s history; another one begins with the consideration of his
further development and his diffusion over the surface of the globe.
The mental qualities which have developed in Man, though traceable in
a vague and rudimentary condition in some of his animal associates,
are of such an unprecedented power and so far dominate everything
else in his activities as a living organism, that they have to a
very large extent, if not entirely, cut him off from the general
operation of that process of Natural Selection and survival of the
fittest which up to their appearance had been the law of the living
world. They justify the view that Man forms a new departure in the
gradual unfolding of Nature’s predestined scheme. Knowledge, reason,
self-consciousness, will, are the attributes of Man. It is not my
purpose to attempt to trace their development from lower phases of
mental activity in man’s animal ancestors, nor even to suggest the
steps by which that development has proceeded. What we call the
will or volition of Man--a discussion of the nature and limitation
of which would be impossible in these pages and is happily not
necessary for my present purpose--has become a power in Nature, an
_imperium in imperio_, which has profoundly modified not only man’s
own history but that of the whole living world and the face of the
planet on which he exists. Nature’s inexorable discipline of death
to those who do not rise to her standard--survival and parentage for
those alone who do--has been from the earliest times more and more
definitely resisted by the will of Man. If we may for the purpose of
analysis, as it were, extract Man from the rest of Nature of which
he is truly a product and part, then we may say that Man is Nature’s
rebel. Where Nature says ‘Die!’ Man says ‘I will live.’ According
to the law previously in universal operation, Man should have been
limited in geographical area, killed by extremes of cold or of heat,
subject to starvation if one kind of diet were unobtainable, and
should have been unable to increase and multiply, just as are his
animal relatives, without losing his specific structure and acquiring
new physical characters according to the requirements of the new
conditions into which he strayed--should have perished except on
the condition of becoming a new morphological ‘species.’ But Man’s
wits and his will have enabled him to cross rivers and oceans by
rafts and boats, to clothe himself against cold, to shelter himself
from heat and rain, to prepare an endless variety of food by fire,
and to ‘increase and multiply’ as no other animal without change of
form, without submitting to the terrible axe of selection wielded by
ruthless Nature over all other living things on this globe. And as
he has more and more obtained this control over his surroundings,
he has expanded that unconscious protective attitude towards his
immature offspring which natural selection had already favoured and
established in the animal race, into a conscious and larger love for
his tribe, his race, his nationality, and his kind. He has developed
speech, the power of communicating, and above all of recording and
handing on from generation to generation his thought and knowledge.
He has formed communities, built cities, and set up empires. At every
step of his progress Man has receded further and further from the
ancient rule exercised by Nature. He has advanced so far and become
so unfitted to the earlier rule, that to suppose that Man can ‘return
to Nature’ is as unreasonable as to suppose that an adult animal can
return to its mother’s womb.
In early tribal times natural selection still imposed the death
penalty on failure. The stronger, the more cunning, the better armed,
the more courageous tribe or family group, exterminated by actual
slaughter or starvation the neighbouring tribes less gifted in one
or all of these qualities. But from what we know of the history of
warlike exterminating savage tribes at the present day--as, for
instance, the Masai of East Africa--it seems unlikely that the method
of extermination--that is, of true natural selection--had much effect
in man’s development after the very earliest period. Union and
absorption were more usual results of the contact of primitive tribes
than struggles to the death. The expulsion of one group by another
from a desired territory was more usual than the destruction of the
conquered. In spite of the frequent assertions to the contrary, it
seems that neither the more ancient wars of mankind for conquest and
migration nor the present and future wars for commercial privilege
have any real equivalence to the simple removal by death of the
unfit and the survival and reproduction of the fit, which we know as
Natural Selection.[7]
The standard raised by the rebel man is not that of ‘fitness’ to the
conditions proffered by extra-human nature, but is one of an ideal
comfort, prosperity, and conscious joy in life--imposed by the will
of man and involving a control and in important respects a subversion
of what were Nature’s methods of dealing with life before she had
produced her insurgent son. The progress of man in the acquirement
of this control of Nature has been one of enormous rapidity
within the historical period, and within the last two centuries
has led on the one hand to immensely increased facilities in the
application of mechanical power, in locomotion, in agriculture,
and in endless arts and industries; and on the other hand to the
mitigation of disease and pain. The men whom we may designate as
‘the Nature-searchers’--those who founded the New Philosophy of the
Invisible College at Oxford and the Royal Society in London--have
placed boundless power in the hands of mankind.
11. THE ATTAINMENT BY MAN OF THE KNOWLEDGE OF HIS RELATIONS TO NATURE.
But to many the greatest result achieved by the progress of
Natural Knowledge seems not to have been so much in its practical
applications and its material gifts to humanity as in the fact that
Man has arrived through it at spiritual emancipation and freedom of
thought.
In the latter part of the last century man’s place in Nature became
clearly marked out by the accumulation of definite evidence. The
significance and the immeasurable importance of the knowledge of
Nature to philosophy and the highest regions of speculative thought
are expressed in the lines of one who most truly and with keenest
insight embodied in his imperishable verse the wisdom and the
aspirations of the Victorian age:--
‘Flower in the crannied wall,
I pluck you out of the crannies:
I hold you here, root and all, in my hand
Little flower--but if I could understand
What you are, root and all, and all in all,
I should know what God and man is.’
To many the nearer approach to that ‘understanding’ has seemed the
greatest and a sufficient result of scientific researches. The
recognition that such an understanding leads to such vast knowledge
would seem to ensure further and combined effort to bring it nearer
and nearer to the complete form, even if the perfect understanding of
the ‘all in all’ be for ever unattainable. Nevertheless, the clearer
apprehension, so recently attained, of man’s origin and destiny, and
of the enormous powers of which he has actually the control, has
not led to any very obvious change in the attitude of responsible
leaders of human activity in the great civilized communities of the
world. They still attach little or no importance to the acquirement
of a knowledge of Nature: they remain fixed in the old ruts of
traditional ignorance, and obstinately turn their faces towards the
past, still believing that the teachings and sayings of antiquity
and the contemplation, not to say the detailed enumeration, of the
blunders and crimes of its ancestors, can furnish mankind with the
knowledge necessary for its future progress. The comparative failure
of what may be called the speculative triumph of the New Philosophy
to produce immediate practical consequences has even led some among
those prejudiced by custom and education in favour of the exclusive
employment of Man’s thought and ingenuity in the delineation and
imaginative resurrection of the youthful follies and excesses of
his race, to declare that the knowledge of Nature is a failure, the
New Philosophy of the Nature-searchers a fraud. Thus the well-known
French publicist M. Brunetière has taken upon himself to declare what
he calls the Bankruptcy of Science.
12. THE REGNUM HOMINIS.
As a matter of fact the new knowledge of Nature--the
newly-ascertained capacity of Man for a control of Nature so thorough
as to be almost unlimited--has not as yet had an opportunity
for showing what it can do. A lull after victory, a lethargic
contentment, has to some extent followed on the crowning triumphs of
the great Nature-searchers whose days were numbered with the closing
years of that nineteenth century which through them marks an epoch.
No power has called on Man to arise and enter upon the possession
of his kingdom--the ‘Regnum Hominis’ foreseen by Francis Bacon and
pictured by him to an admiring but incredulous age with all the
fervour and picturesque detail of which he was capable. And yet at
this moment the mechanical difficulties, the want of assurance and
of exact knowledge, which necessarily prevented Bacon’s schemes from
taking practical shape, have been removed. The will to possess and
administer this vast territory alone is wanting.
13. MAN’S DESTINY.
Within the last few years an attempt to spur the will of Englishmen
in this direction has been made by some who have represented
that this way lie great fortunes, national ascendancy, imperial
domination. The effort has not met with much success. On the other
hand, I speak for those who would urge the conscious and deliberate
assumption of his kingdom by Man--not as a matter of markets and of
increased opportunity for the cosmopolitan dealers in finance--but as
an absolute duty, the fulfilment of Man’s destiny,[8] a necessity the
incidence of which can only be deferred and not avoided.
This, is indeed, the definite purpose of my discourse; to point out
that civilized man has proceeded so far in his interference with
extra-human nature, has produced for himself and the living organisms
associated with him such a special state of things by his rebellion
against natural selection and his defiance of Nature’s pre-human
dispositions, that he must either go on and acquire firmer control of
the conditions or perish miserably by the vengeance certain to fall
on the half-hearted meddler in great affairs. We may indeed compare
civilized man to a successful rebel against Nature who by every step
forward renders himself liable to greater and greater penalties, and
so cannot afford to pause or fail in one single step. Or again we
may think of him as the heir to a vast and magnificent kingdom who
has been finally educated so as to fit him to take possession of his
property, and is at length left alone to do his best; he has wilfully
abrogated, in many important respects, the laws of his mother Nature
by which the kingdom was hitherto governed; he has gained some power
and advantage by so doing, but is threatened on every hand by dangers
and disasters hitherto restrained: no retreat is possible--his only
hope is to control, as he knows that he can, the sources of these
dangers and disasters. They already make him wince: how long will
he sit listening to the fairy-tales of his boyhood and shrink from
manhood’s task?
A brief consideration of well-ascertained facts is sufficient to show
that Man, whilst emancipating himself from the destructive methods
of natural selection, has accumulated a new series of dangers and
difficulties with which he must incessantly contend.
14. MAN AND DISEASE.
In the extra-human system of Nature there is no disease and there
is no conjunction of incompatible forms of life, such as Man has
brought about on the surface of the globe. In extra-human Nature
the selection of the fittest necessarily eliminates those diseased
or liable to disease. Disease both of parasitic and congenital
origin occurs as a minor phenomenon. The congenitally diseased are
destroyed before they can reproduce: the attacks of parasites great
and small either serve only to carry off the congenitally weak, and
thus strengthen the race, or become harmless by the survival of those
individuals which, owing to peculiar qualities in their tissues, can
tolerate such attacks without injury, resulting in the establishment
of immune races. It is a remarkable thing--which possibly may be less
generally true than our present knowledge seems to suggest--that the
adjustment of organisms to their surroundings is so severely complete
in Nature apart from Man, that diseases are unknown as constant and
normal phenomena under those conditions. It is no doubt difficult to
investigate this matter, since the presence of Man as an observer
itself implies human intervention. But it seems to be a legitimate
view that every disease to which animals (and probably plants also)
are liable, excepting as a transient and very exceptional occurrence,
is due to Man’s interference. The diseases of cattle, sheep, pigs,
and horses, are not known except in domesticated herds and those wild
creatures to which Man’s domesticated productions have communicated
them. The trypanosome lives in the blood of wild game and of rats
without producing mischief. The hosts have become tolerant of the
parasite. It is only when man brings his unselected, humanly-nurtured
races of cattle and horses into contact with the parasite, that it
is found to have deadly properties.[9] The various cattle-diseases
which in Africa have done so much harm to native cattle, and have
in some regions exterminated big game, have _per contra_ been
introduced by man through his importation of diseased animals of his
own breeding from Europe. Most, if not all, animals in extra-human
conditions, including the minuter things such as insects, shell-fish,
and invisible aquatic organisms, have been brought into a condition
of ‘adjustment’ to their parasites as well as to the other conditions
in which they live: it is this most delicate and efficient balance
of Nature which Man everywhere upsets. A solitary case of a ravaging
epidemic constantly recurring amongst animals living in extra-human
conditions, one of a strangely interesting character, is the
phosphorescent disease of the sand-shrimps or sand-hoppers. This is
due to a microscopic parasite, a bacterium, which infests the blood
and is phosphorescent, so that the infected sand-hopper has at night
the brilliancy of a glow-worm. The disease is deadly, and is common
among the sand-hoppers dwelling in the sandy flats of the north coast
of France, where it may readily be studied.[10] It has not been
recorded as occurring in this country. It is not at all improbable
that this disease is also in truth one which only occurs in the trail
of Man. It is quite likely that the artificial conditions of sewage
and garbage set up by Man on the sea-coast are responsible for the
prevalence of this parasite, and the weakly receptivity of the too
numerous sand-hoppers.
It is probable enough that, from time to time, under the influence
of certain changes of climate and associated fauna and flora--due
to meteoric or geologic movements--parasitic disease has for a time
ravaged this or that species newly exposed to it; but the final
result is one of the alternatives, extinction or adjustment, death
or toleration. The disease does not establish itself as a scourge
against which the diseased organism incessantly contends. It either
obliterates its victim or settles down with it into relations of
reciprocal toleration.
Man does not admit this alternative either for himself or for
the domesticated and cultivated organisms which he protects. He
‘treats’ disease, he staves off ‘the adjustment by death,’ and thus
accumulates vast populations of unadjusted human beings, animals and
plants, which from time to time are ravaged by disease--producing
uncertainty and dismay in human society. Within the past few years
the knowledge of the causes of disease has become so far advanced
that it is a matter of practical certainty that, by the unstinted
application of known methods of investigation and consequent
controlling action, all epidemic disease could be abolished within
a period so short as fifty years. It is merely a question of the
employment of the means at our command. Where there is one man of
first-rate intelligence employed in detecting the disease-producing
parasites, their special conditions of life and the way to bring
them to an end, there should be a thousand. It should be as much
the purpose of civilized governments to protect their citizens in
this respect as it is to provide defence against human aggression.
Yet it is the fact that this immensely important control of a
great and constant danger and injury to mankind is left to the
unorganized inquiries of a few enthusiasts. So little is this matter
understood or appreciated, that those who are responsible for the
welfare of States, with the rarest exceptions, do not even know that
such protection is possible, and others again are so far from an
intelligent view as to its importance, that they actually entertain
the opinion that it would be a good thing were there more disease in
order to get rid of the weakly surplus population!
In the spring of 1905 I was enabled to examine in the Pasteur
Institute in Paris, the minute spiral thread (see Fig. 6) which has
just been discovered and shown to be the cause of the most terrible
and widely spread of human diseases, destroying the health and
strength of those whom it does not kill and damaging the lives of
their children, so that it has been justly said that this malady and
the use of alcohol as a beverage are together responsible for more
than half the disease and early death of the mature population of
Europe. For more than thirty years, a few workers, here and there,
have been searching for this parasite, and the means of suppressing
the awful curse of which it is the instrument. It would have been
discovered many years ago had greater value been set on the inquiries
which lead to such discoveries by those who direct the public
expenditure of civilized States. And now the complete suppression
of this dire enemy of humanity is as plain and certain a piece of
work to be at once accomplished as is the building of an ironclad.
But it will not be done for many years because of the ignorance
and unbelief of those who alone can act for the community in such
matters. The discovery--the presentation to the eye and to exploring
manipulation--of that well-nigh ultra-microscopic germ of death,
seemed to me, as I gazed at its delicate shape, a thing of greater
significance to mankind than the emendation of a Greek text or the
determination of the exact degree of turpitude of a statesman of a
bygone age.
[Illustration: FIG. 6.
The minute vibratile organism discovered by Fritz Schaudinn in
1905 in the eruptive formations and other diseased growths of
syphilis--and called by him _Spirochæta pallida_ (since altered
to _Spironema pallidum_): _a_, common phase; _b_, shortened and
thickened form leading on to _e_ the Trypanosoma-like form; _c_,
_d_, stages of division by fission; _f_, elongated multi-nuclear
form; _g_, segments into which it breaks up; _h_, supposed
conjugation of male and female units (after Krystallovitch and
Siedlevski).
This organism, though resembling the spirillar forms of Bacteria,
is probably not one of that group of vegetable parasites, but
allied to the minute animal parasites known as Trypanosomes (see
pp. 145 and 181 and figures.) It is regarded as the ‘germ’ or
active cause of the terrible disease known as Syphilis.]
The knowledge of the causation of disease by bacterial and protozoic
parasites is a thing which has come into existence, under our very
eyes and hands, within the last fifty years. The parasite, and much
of its nature and history, has been discovered in the case of splenic
fever, leprosy, phthisis, diphtheria, typhoid fever, glanders,
cholera, plague, lock-jaw, gangrene, septic poisoning (of wounds),
puerperal fever, malaria, sleeping sickness, and some other diseases
which are fatal to man. In some cases the knowledge obtained has
led to a control of the attack or of the poisonous action of the
parasite. Antiseptic surgery, by defeating the poisonous parasite,
has saved not only thousands upon thousands of lives, but has removed
an incalculable amount of pain. Control is slowly being obtained in
regard to several others among these deadly microbes in various ways,
most wonderful of which is the development, under man’s control,
of serums containing antitoxins appropriate to each disease, which
have to be injected into the blood as the means of either cure or
protection. But why should we be content to wait long years, even
centuries, for this control, when we can have it in a few years? If
more men and abler men were employed to study and experiment on
this matter, we should soon make an end of all infectious disease.
Is there any one, man or woman, who would not wish to contribute
to the removal from human life of the suffering and uncertainty
due to disease, the anguish and misery caused by premature death?
Yet nothing is done by those who determine the expenditure of the
revenues of great States towards dealing adequately with this
matter.[11]
15. THE INCREASE OF HUMAN POPULATION.
Whilst there is a certainty of Man’s power to remove all disease
from his life, a difficulty which he has already created for himself
will be thereby increased. That difficulty is the increase of human
population beyond the capacity of the earth’s surface to provide food
and the other necessities of life. By rebelling against Nature’s
method, Man has made himself the only animal which constantly
increases in numbers. Whenever disease is controlled his increase
will be still more rapid than at present. At the same time no
attempt at present has been made by the more advanced communities of
civilized men to prevent the multiplication of the weakly or of those
liable to congenital disease. Already something like a panic on this
subject has appeared in this country. Inquiries have been conducted
by public authorities. But the only possible method of dealing with
this matter, and in the first place of estimating its importance
as immediate or remote, has not been applied. Man can only deal
with this difficulty created by his own departure from Nature--to
which he can never return--by thoroughly investigating the laws of
breeding and heredity, and proceeding to apply a control to human
multiplication based upon certain and indisputable knowledge.
It may be a century, or it may be more than five centuries, before
the matter would, if let alone, force itself upon a desperate
humanity, brutalized by over-crowding, and the struggle for food.
A return to Nature’s terrible selection of the fittest may, it is
conceivable, be in this way in store for us. But it is more probable
that humanity will submit, before that condition occurs, to a
restriction by the community in respect of the right to multiply,
with as good a grace as it has given up the right to murder and to
steal. In view of this Man must, in entering on his kingdom, at once
proceed to perfect those studies as to the transmission of qualities
by heredity which have as yet been only roughly carried out by
breeders of animals and horticulturists.
There is absolutely no provision for this study in any civilized
community, and no conception among the people or their leaders that
it is a matter which concerns any one but farmers.
16. AN UNTOUCHED SOURCE OF ENERGY.
The applications of steam and electricity have so far astonished and
gratified the rebel Man, that he is sometimes disposed to conclude
that he has come to the end of his power of relieving himself from
the use of his own muscles for anything but refined movements and
well-considered health-giving exercises. One of the greatest of
chemical discoverers at this time living, M. Berthelot, has, however,
recently pressed on our attention the question of the possibility
of tapping the central heat of the earth and making use of it as a
perennial source of energy. Many competent physicists have expressed
the opinion that the mechanical difficulties of such a boring, as
would be necessary, are insuperable. No one, however, would venture
to prophesy, in such a matter as this, that what is prevented by
insuperable obstacles to-day may not be within our powers in the
course of a few years.
17. SPECULATIONS AS TO THE MARTIANS.
Such audacious control of the resources of our planet is suggested
as a possibility, a legitimate hope and aim, by recent observations
and speculations as to our neighbour, the planet Mars. I do not
venture to express any opinion as to the interpretation of the
appearances revealed by the telescope on the surface of the planet
Mars, and indeed would take the most sceptical attitude until further
information is obtained. But the influence of these statements about
Mars on the imagination and hopes of Man seems to me to possess
considerable interest. The markings on the surface of the planet
Mars, which have been interpreted as a system of canals, have
been known and discussed for many years (see Figs. 7 and 8). It
has recently been observed that these canals undergo a recurrent
seasonal change of appearance consistent with the hypothesis that
they are periodically filled with water, which is derived from the
polar snow-caps of the planet at the season of greatest polar heat.
It is suggested that Mars is inhabited by an intelligent population,
not necessarily closely similar to mankind, but, on the contrary
unlike mankind in proportion as the conditions of Mars are unlike
those of the Earth, and that these inhabitants have constructed
by their own efforts the enormous irrigation works upon which the
fertility and habitability of their planet, at the present time,
depend. These speculations lead M. Faguet of the French Academy to
further reflections. The Martians who have carried out this vast
manipulation of a planet must be not only far in advance of the
inhabitants of the Earth in intelligence and mechanical power, as a
result of the greater age of their planet and the longer continuance
there of the evolution of an intelligent race, but such a vast work
and its maintenance would seem to imply a complete unanimity among
the Martians, a world-wide peace and common government. Since we
can imagine such a result of the prolonged play of forces in Mars,
similar to those at work in our own Earth, and even obtain some
slight confirmation of the supposition, may we not indulge in the
surmise that some such future is in store for Man, that he may be
able hereafter to deal with great planetary factors to his own
advantage, and not only draw heat from the bowels of the earth for
such purposes as are at present within his scope, but even so as to
regulate, at some distant day, the climates of the earth’s surface,
and the winds and the rain which seem now for ever beyond his control?
[Illustration: FIG. 7.
Drawing of Mars in November with Long. 156° on the meridian,
shewing the ‘Mare Sirenum’ (the shaded sickle-shaped area),
connected with a network of ‘canals’ shewing ‘spots’ or ‘oases’
at the intersections of the canals and a system of spherical
triangles as the form of the mesh-work.--_From_ ‘Mars,’ by
Perceval Lowell.]
[Illustration: FIG. 8.
Drawing of Mars as seen on November 18th, 1894 (Long. 325° on the
meridian) by Mr. Perceval Lowell at the Flagstaff Observatory,
Arizona, U.S.A., shewing ‘twin’ or ‘double’ canals, connected
northwards with the ‘Mare Icarium.’ The two figures here
reproduced only give a small portion of the system of canals,
oases and seas of the planet Mars, mapped by Mr. Lowell.]
18. THE INVESTIGATION OF THE HUMAN MIND.
In such a desultory survey as that on which I have ventured, of Man’s
kingdom and its dangers, it occurs to me to mention another area
upon which it seems urgent that the activities of nature-searchers
should be immediately turned with increased power and number. The
experimental study of his body and of that of animals has been
carried far and with valuable results by inquiring Man. But a
singularly small amount of attention has as yet been given to the
investigation of Man’s mind as a natural phenomenon and one which can
be better understood to the immense advantage of the race.
The mind of Man--it matters not for my immediate argument whether
it be regarded as having arisen normally or abnormally from the
mind of animals--is obviously the one and all-powerful instrument
with which he has contended, and is destined hereafter to contend,
against extra-human Nature. It is no less important for him to know
the quality, the capacity, the mode of operation of this instrument,
its beginnings and its limitations, than it is for him to know the
minutest details of the workings of Nature. Just as much in the
one case as in the other, it is impossible for him to trust to the
imperfect analysis made by ancient races of men and the traditions
and fancies handed down in old writings--produced by generations
who had not arrived at the method of investigation which we now
can apply. Experiment upon the mental processes of animals and of
Man is greatly needed. Only here and there has anything been done
in this direction. Most promising results have been obtained by
such observations as those on hypnotism and on various diseased and
abnormal states of the brain. But the subject is so little explored
that wild and untested assertions as to the powers of the mind are
current and have given rise to strange beliefs, accepted by many
seriously-intentioned men and women. We boldly operate upon the minds
of children in our systems of education without really knowing what
we are doing. We blindly assume that the owners of certain minds,
traditionally trained in amusing elegancies, are fit to govern
their fellow-men and administer vast provinces; we assume that the
discovery and comprehension of Nature’s processes must be the work
of very few and peculiar minds; that if we take care of the body the
mind will take care of itself. We know really nothing of the heredity
of mental qualities, nor how to estimate their presence or absence in
the young so as to develop the mind to greatest advantage. We know
the pain and the penalty of muscular fatigue, but we play with the
brains of young and old as though they were indestructible machinery.
What is called experimental psychology is only in its infancy, but
it is of urgent necessity that it should be systematically pursued
by the application of public funds in order that Man may know how
to make the best use of his only weapon in his struggle to control
Nature.
19. MAN’S DELAY: ITS CAUSE AND REMEDY.
Even the slight and rapid review just given of Man’s position, face
to face with Nature, enables us to see what a tremendous step he has
taken, what desperate conditions he has created by the wonderful
exercise of his will; how much he has done and can do to control the
order of Nature, and how urgent it is, beyond all that words can say,
for him to apply his whole strength and capacity to gaining further
control, so that he may accomplish his destiny and escape from misery.
It is obvious enough that Man is, at present, doing very little in
this direction; so little that one seeks for an explanation of his
apathy, his seeming paralysis.
The explanation is that the masses of the people, in civilized as
well as uncivilized countries, are not yet aware of the situation.
When knowledge on this matter reaches, as it inevitably will in time,
to the general population, it is certain that the democracy will
demand that those who expend the resources of the community, and
as government officials undertake the organization of the national
defence and other great public services for the common good, shall
put into practice the power of Nature-control which has been gained
by mankind, and shall exert every sinew to obtain more. To effect
this, the democracy will demand that those who carry on public
affairs shall not be persons solely acquainted with the elegant
fancies and stories of past ages, but shall be trained in the
acquisition of natural knowledge and keenly active in the skilful
application of Nature-control to the development of the well-being of
the community.
It would not be necessary to wait for this pressure from below were
the well-to-do class--which in most modern States exercises so
large an influence both in the actual administration of Governments
and by example--so situated as to be in any way aware of the
responsibilities which rest upon it. Traditional education has, owing
to causes which are not far to seek, deprived the well-to-do class
of a knowledge of, and interest in, Man’s relation to Nature, and
of his power to control natural processes. During the whole period
of the growth of man’s knowledge of Nature--that is to say, ever
since the days of Bruno--the education of the well-to-do has been
directed to the acquirement of entertaining information and elegant
accomplishments, whilst ‘useful knowledge’ has been despised and
obtained, when considered necessary, from lower-class ‘workmen’ at
workmen’s wages. It is of course not to be overlooked that there
have been notable exceptions to this, but they have been exceptions.
Even at the present day, in some civilized States, a body of clerks,
without any pretence to an education in the knowledge of Nature,
headed by gentlemen of title, equally ignorant, are entrusted with,
and handsomely paid and rewarded for, the superintendence of the
armies, the navies, the agriculture, the public works, the fisheries,
and even the public education of the State. When compelled to seek
the assistance of those who have been trained in the knowledge of
Nature (for even in these States there are a few such eccentric
persons to be found), the officials demand that such assistance
shall be freely given to them without pay, or else offer to buy the
knowledge required at the rate paid to a copying clerk.
This state of things is not one for which it is possible to blame
those who, in blissful ignorance, contentedly perform what they
consider to be their duty to their country. There are, however, in
many States, institutions, of vast influence in the education of
the whole community, known as Universities. In many countries they
as well as the schools are directly controlled by the State. In
England, however, we are happy in having free Universities, the older
of which, though in some important respects tied down by law, yet
have the power to determine almost absolutely, not only what shall be
studied within their own walls, but what shall be studied in all the
schools of the country frequented by the children of the well-to-do.
It is the pride of our ancient Universities that they are largely, if
not exclusively, frequented by young men of the class who are going
to take an active part in the public affairs of the country--either
as politicians and statesmen, as governors of remote colonies, or
as leaders of the great professions of the Church, the Law, and
Medicine. It would seem, then, that if these Universities attached a
greater, even a predominant, importance to the studies which lead to
the knowledge and control of Nature, the schools would follow their
example, and that the governing class of the country would become
acquainted with the urgent need for more knowledge of the kind, and
for the immediate application in public affairs of that knowledge
which exists.
It would seem that in Great Britain, at any rate, it would not be
necessary, were the Universities alive to the situation, to await
the pressure of democracy, but that a better and more rapid mode of
development would obtain; the influential and trusted leaders of
the community would set the example in seeking and using for the
good of the State the new knowledge of Nature. The world has seen
with admiration and astonishment the entire people of Japan follow
the example of its governing class in the almost sudden adoption
of the knowledge and control of Nature as the purpose of national
education and the guide of State administration. It is possible that
in a less rapid and startling manner our old Universities may, at no
distant date, influence the intellectual life of the more fortunate
of our fellow citizens, and consequently of the entire community.
The weariness which is so largely expressed at the present day in
regard to human effort--whether it be in the field of politics, of
literature, or of other art, or in relation to the improvement of
social organization and the individual life--is possibly due to the
fact that we have exhausted the old sources of inspiration, and have
not yet learnt to believe in the new. The ‘return to Nature,’ which
is sometimes vaguely put forward as a cure for the all-pervading
‘taedium’ of this age, is perhaps an imperfect expression of the
truth that it is time for civilized man not to return to the ‘state
of Nature,’ but to abandon his retrospective attitude and to take
up whole-heartedly the Kingdom of Nature which it is his destiny
to rule. New hope, new life will, when he does this, be infused
into every line of human activity: Art will acquire a new impulse,
and politics become real and interesting. To a community which
believes in the destiny of Man as the controller of Nature, and has
consciously entered upon its fulfilment, there can be none of the
weariness and even despair which comes from an exclusive worship
of the past. There can only be encouragement in every victory
gained, hope and the realization of hope. Even in the face of the
overwhelming opposition and incredulity which now unhappily have
the upper hand, the believer in the predestined triumph of Man over
Nature can exert himself to place a contribution, however small,
in the great edifice of Nature-knowledge, happy in the conviction
that his life has been worth living, has counted to the good in the
imperishable result.
20. THE INFLUENCE OF OXFORD.
If I venture now to consider more specifically the influence
exercised by the University of Oxford upon the welfare of the State
and of the human community in general, in view of the conclusions
which have been set forth in what has preceded, I beg to say that I
do so with the greatest respect to the opinions of others who differ
from me. When I say this I am not using an empty formula. I mean that
I believe that there must be many University men who are fair-minded
and disinterested, and have given special attention to the matter of
which I wish to speak, and who are yet very far from agreeing with
me. I ask them to consider what I have said, and what I have further
to say, in the same spirit as that in which I approach them.
It seems to me--and when I speak of myself I would point out that I
am presenting the opinions of a large number of educated men, and
that it will be better for me to avoid an egotistical attitude--it
seems to us (I prefer to say) that the University of Oxford by its
present action in regard to the choice and direction of subjects of
study is exercising an injurious influence upon the education of
the country, and especially upon the education of those who will
hereafter occupy positions of influence, and will largely determine
both the action of the State and the education and opinions of those
who will in turn succeed them. The question has been recently raised
as to whether the acquirement of a certain elementary knowledge of
the Greek language should be required of all those who desire to
pursue their studies in this University, and accordingly whether the
teaching of the elements of this language should form a prominent
feature in the great schools of this country. It seems to us that
this is only part of a much larger question; namely, whether it is
desirable to continue to make the study of two dead languages--and
of the story of the deeds of great men in the past--the main if
not the exclusive matter to which the minds of the youth of the
well-to-do class are directed by our schools and universities. We
have come to the conclusion that this form of education is a mistaken
and injurious one. We desire to make the chief subject of education
both in school and in college a knowledge of Nature as set forth in
the sciences which are spoken of as physics, chemistry, geology,
and biology. We think that all education[12] should consist in the
first place of this kind of knowledge, on account of its commanding
importance both to the individual and to the community. We think that
every man of even a moderate amount of education should have acquired
a sufficient knowledge of these subjects to enable him at any rate
to appreciate their value, and to take an interest in their progress
and application to human life. And we think further that the ablest
youths of the country should be encouraged to proceed to the extreme
limit of present knowledge in one or other branch of this knowledge
of Nature so as to become makers of new knowledge, and the possible
discoverers of enduring improvements in man’s control of Nature. No
one should be educated so as to be ignorant of the importance of
these things; and it should not be possible for the greatest talent
and mental power to be diverted to other fields of activity through
the fact that the necessary education and opportunity in the pursuit
of the knowledge of Nature are withheld. The strongest inducements in
the way of reward and consideration ought, we believe, to be placed
before a young man in the direction of Nature-knowledge rather than
in the direction of other and far less important subjects of study.
In fact, we should wish to see the classical and historical scheme
of education entirely abandoned, and its place taken by a scheme of
education in the knowledge of Nature.
At the same time let me hasten to say that few, if any of us--and
certainly not he who writes these lines--would wish to remove the
acquirement of the use of languages, the training in the knowledge
and perception of beauty in literary art, and the feeding of the
mind with the great stories of the past, from a high and necessary
position in every grade of education.
It is a sad and apparently inevitable accompaniment of all discussion
of this matter that those who advocate a great and leading position
for the knowledge of Nature in education are accused of desiring
to abolish all study of literature, history, and philosophy. This
is, in reality, so far from being the case that we should most
of us wish to see a serviceable knowledge of foreign languages,
and a real acquaintance with the beauties of English and other
literature, substituted for the present unsuccessful efforts to
teach effectively either the language or literature of the Greeks and
Romans.
It should not be for one moment supposed that those who attach the
vast importance which we do to the knowledge of Nature imagine that
Man’s spirit can be satisfied by exclusive occupation with that
knowledge. We know, as well as any, that Man does not live by bread
alone. Though the study of Nature is fitted to develop great mental
qualities--perseverance, honesty, judgement, and initiative--we
do not suppose that it completes Man’s mental equipment. Though
the knowledge of Nature calls upon, excites, and gratifies the
imagination to a degree and in a way which is peculiar to itself,
we do not suppose that it furnishes the opportunity for all forms
of mental activity. The great joys of Art, the delights and
entertainment to be derived from the romance and history of human
character, are not parts of it. They must never be neglected. But
are we not justified in asserting that, for some two hundred years
or more, these ‘entertainments’ have been pursued in the name of the
highest education and study to the exclusion of the far weightier
and more necessary knowledge of Nature? ‘This should ye have done,
and yet not left the other undone,’ may justly be said to those who
have conducted the education of our higher schools and universities
along the pleasant lines of literature and history, to the neglect
of the urgently-needed ‘improvement of Natural Knowledge.’ Nero was
probably a musician of taste and training, and it was artistic and
high-class music which he played while Rome was burning: so too the
studies of the past carried on at Oxford have been charming and full
of beauty, whilst England has lain, and lies, in mortal peril for
lack of knowledge of Nature.
It seems to be beyond dispute that the study, firstly of Latin,
and much more recently of Greek, were followed in our Universities
and in grammar schools, not as educational exercises in the use of
language, but as keys to unlock the store-rooms--the books--in which
the knowledge of the ancients was contained. So long as these keys
were needed, it was reasonable enough that every well-educated man
should spend such time as was necessary in providing himself with the
key. But now that the store-rooms are empty--now that their contents
have been appropriated and scattered far and wide--in all languages
of civilization, it seems to be merely an unreasoning continuation of
superannuated custom to go on with the provision of these keys. Such,
however, is the force of habit that it continues: new and ingenious
reasons for the practice are put forward, whilst its original object
is entirely forgotten.
In the first place, it has come to be regarded as a mark of good
breeding, and thus an end in itself, for a man to have some
first-hand acquaintance with Latin and Greek authors, even when he
knows no other literature. It is a fashion, like the wearing of a
court dress. This cannot be held to justify the employment of most of
the time and energy of youth in its acquirement.
A second reason which is now put forward for the practice is that
the effort and labour expended on the provision of these keys--even
though it is admitted that they are useless--are a wonderful and
incomparably fine exercise of the mind, fitting it for all sorts of
work. A theory of education has been enunciated which fits in with
this defence of the continued attempt to compel young men to acquire
a knowledge, however imperfect, of the Latin and Greek languages.
It is held that what is called ‘training the mind’ is the chief,
if not the only proper, aim of education; and it is declared that
the continuation of the study of those once useful, but now useless,
keys--Latin and Greek--is an all-sufficient training. If this
theory were in accordance with the facts, the conclusion in favour
of giving a very high place to the study so recommended would be
inevitable. But the facts do not support this theory. Clever youths
are taken and pressed into the study of Greek and Latin, and we are
asked to conclude that their cleverness is due to these studies. On
the other hand, we maintain that though the study of grammar may
be, when properly carried out, a valuable exercise, yet that it is
easily converted into a worthless one, and can never in any case take
the place of various other forms of mental training, such as the
observation of natural objects, the following out of experimental
demonstration of the qualities and relations of natural bodies, and
the devising and execution of experiment as the test of hypothesis.
Apart from ‘training’ there is the need for providing the mind with
information as well as method. The knowledge of Nature is eagerly
assimilated by young people, and no training in mental gymnastics can
be a substitute for it or an excuse for depriving the young of what
is of inestimable value and instinctively desired.
The prominence which is assigned to a familiarity with the details of
history, more especially of what may be called biographical history,
in the educational system favoured by Oxford, seems to depend on the
same causes as those which have led to the maintenance of the study
of Greek and Latin. To read history is a pleasant occupation which
has become a habit and tradition. At one time men believed that
history repeats itself, and it was thought to be a proper and useful
training for one who would take part in public affairs to store
his mind with precedents and picturesque narratives of prominent
statesmen and rulers in far-off days and distant lands. As a matter
of fact it cannot be shown that any statesman, or even the humblest
politician, has ever been guided to useful action by such knowledge.
History does not repeat itself, and the man who thinks that it does
will be led by his fragmentary knowledge of stories of the past into
serious blunders. To the fashionable journalist such biographical
history furnishes the seasoning for his essays on political questions
of the day. But this does not seem to be a sufficient reason for
assigning so prominent a place in University studies to this kind of
history as is at present the case. The reason, perhaps, of the favour
which it receives, is that it is one of the few subjects which a
man of purely classical education can pursue without commencing his
education in elementary matters afresh.
It would be a serious mistake[13] to suppose that those who would
give a complete supremacy to the study of Nature, in our educational
system, do not value and enjoy biographical history for what it is
worth as an entertainment; or further, that they do not set great
value upon the scientific study of the history of the struggles of
the races and nations of mankind, as a portion of the knowledge of
the evolution of Man, capable of giving conclusions of great value
when it has been further and more thoroughly treated as a department
of Anthropology. What seems to us undesirable is, that mere stories
and bald records of certain peoples should be put forward as matter
with which the minds of children and young men are to be occupied, to
the exclusion of the all-important matters comprised in the knowledge
of Nature.
There are, it is well known, not a few who regard the present
institution of Latin and Greek and so-called History, in the
pre-eminent place which they occupy in Oxford and the great schools
of the country, as something of so ancient and fundamental a
character that to question the wisdom of that institution seems an
odious proceeding, partaking of the nature of blasphemy. This state
of mind takes its origin in a common error, due to the fact that a
straightforward account of the studies pursued in the University
during the last five hundred years has never been written. Our
present curriculum is a mere mushroom growth of the last century,
and has no claim whatever to veneration. Greek was studied by but a
dozen or two specialists in Oxford two hundred and fifty years ago.
In those days, in proportion to what had been ascertained in that
subject and could be taught, there was a great and general interest
in the University in the knowledge of Nature, such as we should
gladly see revived at the present day. As a matter of fact, it is
only within the last hundred years that the dogma of compulsory
Greek, and the value of what is now called a classical education, has
been promulgated. These things are not historically of ancient date;
they are not essentials of Oxford. We are therefore well within our
right in questioning the wisdom of their continuance in so favoured a
position, and we are warranted in expressing the hope that those who
can change the policy of the University and Colleges in this matter
will, at no distant day, do so.
It is sometimes urged that Oxford should contentedly resign herself
to the overwhelming predominance given to the study of ancient
elegance and historic wisdom within her walls. It is said that
she may well be reserved for these delightful pursuits, whilst
newer institutions should do the hard work of aiding man in his
conquest of Nature. At first sight such a proposal has a tempting
character: we are charmed with the suggestion that our beautiful
Oxford should be enclosed by a ring fence and cut off for ever from
the contamination of the world. But a few moments’ reflection must
convince most of us that such a treatment of Oxford is an insult to
her and an impossibility. Oxford is not dead. Only a few decades have
passed--a mere fraction of her lifetime--since she was free from the
oppression of grammar-school studies, and sent forth Robert Boyle and
Christopher Wren to establish the New Philosophy of the Invisible
College in London. She seems, to some of us, to have been used not
quite wisely, perhaps not quite fairly, in the brief period which
has elapsed since that time. Why should she not shake herself free
again, and give, hereafter, most, if not the whole, of her wealth and
strength to the urgent work which is actually pursued in every other
University of the world as a chief aim and duty?
The fact that Oxford attracts the youth of the country to her,
and so determines the education offered in the great schools, is
a sufficient answer to those who wish to perpetuate the present
employment of her resources in the subvention and encouragement of
comparatively unimportant, though fascinating (even too fascinating),
studies, to the neglect of the pressing necessary knowledge of
Nature. Those who enjoy great influence in the affairs of the
University tell us with pride that Oxford not only determines what
our best schools shall teach, but has, as a main pre-occupation,
the education of statesmen, pro-consuls, leaders of the learned
professions, and members of parliament! Undoubtedly this claim is
well-founded, and its truth is the reason why we cannot be content
with the maintenance by the University of the compulsory study of
Greek and Latin, and the neglect to make the study of Nature an
integral and predominant part of every man’s education.
To return to my original contention--the knowledge and control of
Nature is Man’s destiny and his greatest need. To enable future
leaders of the community to comprehend this, to perceive what the
knowledge and control of Nature are, and what are the steps by which
they are gained and increased, is the duty of a great University. To
neglect this is to retard the approach of well-being and happiness,
and to injure humanity.
I beg, finally, for toleration from those who do not share my
opinions. I am well aware that they are open to the objection that
they partake more of the nature of dreams of the future than of
practical proposals.[14] That, perhaps, may be accepted as my excuse
for indulging in them. There are, and always have been, dreamers
in Oxford, and beautiful dreams they have dreamed--some of the
past, and some of the future. The most fascinating dreams are not,
unfortunately, always realized; but it is sometimes worth while to
tell one’s dream, for that may bring it a step nearer to ‘coming
true.’
APPENDIX.
_I add here a brief statement published by me in the_ TIMES, _May
17th, 1903, which touches on the question of the origin of life,
and certain theories of creation._
“It seems to me that, were the discussion excited by Lord Kelvin’s
statements to the Christian Association at University College allowed
to close in its present phase, the public would be misled and
injustice done both to Lord Kelvin and his critics. I therefore beg
you to allow me to point out what appear to me to be the significant
features of the matter under discussion.
“Lord Kelvin, whose eminence as a physicist gives a special interest
to his opinion upon any subject, made at University College, or in
his subsequent letter to you, the following statements:--
“1. That ‘fortuitous concourse of atoms’ is not an inappropriate
description of the formation of a crystal.
“2. That ‘fortuitous concourse of atoms’ is utterly absurd in respect
to the coming into existence, or the growth, or the continuation of
the molecular combinations presented in the bodies of living things.
“3. That, though inorganic phenomena do not do so, yet the
phenomena of such living things as a sprig of moss, a microbe, a
living animal--looked at and considered as matters of scientific
investigation--compel us to conclude that there is scientific reason
for believing in the existence of a creative and directive power.
“4. That modern biologists are coming once more to a firm acceptance
of something, and that is--a vital principle.
“In your article on the discussion which has followed these
statements you declare that this (the opinions I have quoted above)
is ‘a momentous conclusion,’ and that it is a vital point in the
relation of science to religion.
“I do not agree with that view of the matter, although I find Lord
Kelvin’s statements full of interest. So far as I have been able to
ascertain, after many years in which these matters have engaged my
attention, there is no relation, in the sense of a connection or
influence, between science and religion. There is, it is true, often
an antagonistic relation between exponents of science and exponents
of religion when the latter illegitimately misrepresent or deny
the conclusions of scientific research or try to prevent its being
carried on, or, again, when the former presume, by magnifying the
extremely limited conclusions of science, to deal in a destructive
spirit with the very existence of those beliefs and hopes which are
called ‘religion.’ Setting aside such excusable and purely personal
collisions between rival claimants for authority and power, it
appears to me that science proceeds on its path without any contact
with religion, and that religion has not, in its essential qualities,
anything to hope for, or to fear from, science.
“The whole order of nature, including living and lifeless
matter--from man to gas--is a network of mechanism the main features
and many details of which have been made more or less obvious to the
wondering intelligence of mankind by the labour and ingenuity of
scientific investigators. But no sane man has ever pretended, since
science became a definite body of doctrine, that we know or ever
can hope to know or conceive of the possibility of knowing, whence
this mechanism has come, why it is there, whither it is going, and
what there may or may not be beyond and beside it which our senses
are incapable of appreciating. These things are not ‘explained’ by
science, and never can be.
“Lord Kelvin speaks of a ‘fortuitous concourse of atoms,’ but I
must confess that I am quite unable to apprehend what he means by
that phrase in the connection in which he uses it. It seems to me
impossible that by ‘fortuitous’ he can mean something which is not
determined by natural cause and therefore is not part of the order
of nature. When an ordinary man speaks of a concourse having arisen
‘by chance’ or ‘fortuitously,’ he means merely that the determining
conditions which have led by natural causation to its occurrence were
not known to him beforehand; he does not mean to assert that it has
arisen without the operation of such determining conditions; and I
am quite unable to understand how it can be maintained that ‘the
concourse of atoms’ forming a crystal, or even a lump of mud, is in
any philosophic sense more correctly described as ‘fortuitous’ than
is the concourse of atoms which has given rise to a sprig of moss
or an animal. It would be a matter of real interest to many of your
readers if Lord Kelvin would explain more precisely what he means
by the distinction which he has, somewhat dogmatically, laid down
between the formation of a crystal as ‘fortuitous’ and the formation
of an organism as due to ‘creative and directive purpose.’
“I am not misrepresenting what Lord Kelvin has said on this subject
when I say that he seems to have formed the conception of a creator
who, first of all, without care or foresight, has produced what we
call ‘matter,’ with its necessary properties, and allowed it to
aggregate and crystallise as a painter might allow his pigments to
run and intermingle on his palette; and then, as a second effort, has
brought some of these elements together with ‘creative and directive
purpose,’ mixing them, as it were, with ‘a vital principle’ so as
to form living things, just as the painter might pick out certain
colours from his confused palette and paint a picture.
“This conception of the intermittent action of creative power and
purpose does not, I confess, commend itself to me. That, however,
is not so surprising as that it should be thought that this curious
conception of the action of creative power is of value to religion.
Whether the intermittent theory is a true or an erroneous conception
seems to me to have nothing to do with ‘religion’ in the large
sense of that word so often misused. It seems to me to be a kind
of mythology, and I should have thought could be of no special
assistance to teachers of Christianity. Such theories of divided
creative operations are traceable historically to polytheism.
“Lastly, with reference to Lord Kelvin’s statement that ‘modern
biologists are coming once more to a firm acceptance of
something--and that is “a vital principle.”’ I will not venture to
doubt that Lord Kelvin has such persons among his acquaintance.
On the other hand, I feel some confidence in stating that a more
extensive acquaintance with modern biologists would have led Lord
Kelvin to perceive that those whom he cites are but a trifling
percentage of the whole. I do not myself know of any one of admitted
leadership among modern biologists who is showing signs of ‘coming to
a belief in the existence of a vital principle.’
“Biologists were, not many years ago, so terribly hampered by these
hypothetical entities--‘vitality,’ ‘vital spirits,’ ‘anima animans,’
‘archetypes,’ ‘vis medicatrix,’ ‘providential artifice,’ and others
which I cannot now enumerate--that they are very shy of setting any
of them up again. Physicists, on the other hand, seem to have got
on very well with their problematic entities, their ‘atoms’ and
‘ether,’ and ‘the sorting demon of Maxwell.’ Hence, perhaps, Lord
Kelvin offers to us, with a light heart, the hypothesis of a ‘a vital
principle’ to smooth over some of our admitted difficulties. On the
other hand, we biologists, knowing the paralysing influence of such
hypotheses in the past, are as unwilling to have anything to do with
‘a vital principle,’ even though Lord Kelvin erroneously thinks
we are coming to it, as we are to accept other strange ‘entities’
pressed upon us by other physicists of a modern and singularly
adventurous type. Modern biologists (I am glad to be able to affirm)
do not accept the hypothesis of ‘telepathy’ advocated by Sir Oliver
Lodge, nor that of the intrusions of disembodied spirits pressed upon
them by others of the same school.
“We biologists take no stock in these mysterious entities. We think
it a more helpful method to be patient and to seek by observation of,
and experiment with, the phenomena of growth and development to trace
the evolution of life and of living things without the facile and
sterile hypothesis of ‘a vital principle.’ Similarly, we seek by the
study of cerebral disease to trace the genesis of the phenomena which
are supposed by some physicists who have strayed into biological
fields to justify them in announcing the ‘discovery’ of ‘telepathy’
and a belief in ghosts.”
CHAPTER II
_THE ADVANCE OF SCIENCE, 1881-1906_
I propose to give in the following pages an outline of the advance of
science in the past twenty-five years. It is necessary to distinguish
two main kinds of advancement, both of which are important. Francis
Bacon gave the title ‘Advancement of Learning’ to that book in
which he explained not merely the methods by which the increase of
knowledge was possible, but advocated the promotion of knowledge to
a new and influential position in the organization of human society.
His purpose, says Dean Church, was ‘to make knowledge really and
intelligently the interest, not of the school or the study or the
laboratory only, but of society at large.’ So that in surveying the
advancement of science in the past quarter of a century we should
ask not only what are the new facts discovered, the new ideas and
conceptions which have come into activity, but what progress has
science made in becoming really and intelligently the interest of
society at large. Is there evidence that there is an increase in
the influence of science on the lives of our fellow-citizens and
in the great affairs of the State? Is there an increased provision
for securing the progress of scientific investigation in proportion
to the urgency of its need or an increased disposition to secure
the employment of really competent men trained in scientific
investigation for the public service?
1. THE INCREASE OF KNOWLEDGE IN THE SEVERAL BRANCHES OF SCIENCE.
The boundaries of my own understanding and the practical
consideration of what is appropriate to a brief essay must limit my
attempt to give to the general reader some presentation of what has
been going on in the workshops of science in this last quarter of a
century. My point of view is essentially that of the naturalist, and
in my endeavour to speak of some of the new things and new properties
of things discovered in recent years I find it is impossible to give
any systematic or detailed account of what has been done in each
division of science. All that I shall attempt is to mention some of
the discoveries which have aroused my own interest and admiration.
I feel, indeed, that it is necessary to ask forbearance for my
presumption in daring to treat of so many subjects in which I cannot
claim to speak as an authority, but only as a younger brother full
of fraternal pride and sympathy in the glorious achievements of the
great experimentalists and discoverers of our day.
As one might expect, the progress of the Knowledge of Nature (for
it is to that rather than to the historical, moral and mental
sciences that English-speaking people refer when they use the word
‘science’) has consisted, in the last twenty-five years, in the
amplification and fuller verification of principles and theories
already accepted, and in the discovery of hitherto unknown things
which either have fallen into place in the existing scheme of each
science or have necessitated new views, some not very disturbing
to existing general conceptions, others of a more startling and,
at first sight, disconcerting character. Nevertheless I think I am
justified in saying that, exciting and of entrancing interest as
have been some of the discoveries of the past few years, there has
been nothing to lead us to conclude that we have been on the wrong
path--nothing which is really revolutionary; that is to say, nothing
which cannot be accepted by an intelligible modification of previous
conceptions. There is, in fact, continuity and healthy evolution in
the realm of science. Whilst some onlookers have declared to the
public that science is at an end, its possibilities exhausted, and
but little of the hopes it raised realised, others have asserted on
the contrary, that the new discoveries--such as those relating to the
X-rays and to radium--are so inconsistent with previous knowledge as
to shake the foundations of science, and to justify a belief in any
and every absurdity of an unrestrained fancy. These two reciprocally
destructive accusations are due to a class of persons who must be
described as the enemies of science. Whether their attitude is due
to ignorance or traditions of self-interest, such persons exist. It
is one of the objects of our scientific associations and societies
to combat those assertions and to demonstrate, by the discoveries
announced at their meetings and the consequent orderly building up of
the great fabric of ‘natural knowledge,’ that Science has not come
to the end of her work--has, indeed, only as yet given mankind a
foretaste of what she has in store for it--that her methods and her
accomplished results are sound and trustworthy, serving with perfect
adaptability for the increase of true discovery and the expansion and
development of those general conceptions of the processes of nature
at which she aims.
_New Chemical Elements._--There can be no doubt that the past quarter
of a century will stand out for ever in human history as that in
which new chemical elements, not of an ordinary type, but possessed
of truly astounding properties, were made known with extraordinary
rapidity and sureness of demonstration. Interesting as the others
are, it is the discovery of radio-activity and of the element radium
which so far exceeds all others in importance that we may well
account it a supreme privilege that it has fallen to our lot to live
in the days of this discovery. No single discovery ever made by
the searchers of nature even approaches that of radio-activity in
respect of the novelty of the properties of matter suddenly revealed
by it. A new conception of the structure of matter is necessitated
and demonstrated by it, and yet, so far from being destructive
and disconcerting, the new conception fits in with, grows out of,
and justifies the older schemes which our previous knowledge has
formulated.
Before saying more of radio-activity, which is apt to eclipse in
interest every other topic of discourse, I must recall to you
the discovery of the five inert gaseous elements by Rayleigh and
Ramsay, which belongs to the period on which we are looking back.
It was found that nitrogen obtained from the atmosphere invariably
differed in weight from nitrogen obtained from one of its chemical
combinations; and thus the conclusion was arrived at by Rayleigh
that a distinct gas is present in the atmosphere, to the extent
of 1 per cent., which had hitherto passed for nitrogen. This gas
was separated, and to it the name argon (the lazy one) was given,
on account of its incapacity to combine with any other element.
Subsequently this argon was found by Ramsay to be itself impure,
and from it he obtained three other gaseous elements equally inert:
namely neon, krypton, and xenon. These were all distinguished from
one another by the spectrum, the sign-manual of an element given by
the light emitted in each case by the gas when in an incandescent
condition. A fifth inert gaseous element was discovered by Ramsay as
a constituent of certain minerals which was proved by its spectrum
to be identical with an element discovered twenty-five years ago by
Sir Norman Lockyer in the atmosphere of the sun, where it exists in
enormous quantities. Lockyer had given the name ‘helium’ to this new
solar element, and Ramsay thus found it locked up in certain rare
minerals in the crust of the earth.
But by helium we are led back to radium, for it has been found only
two years ago by Ramsay and Soddy that helium is actually formed by
a gaseous emanation from radium. Astounding as the statement seems,
yet that is one of the many unprecedented facts which recent study
has brought to light. The alchemist’s dream is, if not realised, at
any rate justified. One element is actually under our eyes converted
into another; the element radium decays into a gas which changes into
another element, namely helium.
Radium, this wonder of wonders, was discovered owing to the study of
the remarkable phosphorescence, as it is called--the glowing without
heat--of glass vacuum-tubes through which electric currents are
made to pass. Crookes, Lenard, and Röntgen each played an important
part in this study, showing that peculiar rays or linear streams of
at least three distinct kinds are set up in such tubes--rays which
are themselves invisible, but have the property of making glass or
other bodies which they strike glow with phosphorescent light. The
celebrated Röntgen rays make ordinary glass give out a bright green
light; but they pass through it, and cause phosphorescence outside
in various substances, such as barium platino-cyanide, calcium
tungstate, and many other such salts; they also act on a photographic
plate and discharge an electrified body such as an electroscope. But
the most remarkable feature about them is their power of penetrating
substances opaque to ordinary light. They will pass through thin
metal plates or black paper or wood, but are stopped by more or
less dense material. Hence it has been possible to obtain ‘shadow
pictures’ or skiagraphs by allowing the invisible Röntgen rays to
pass through a limb or even a whole animal, the denser bone stopping
the rays, whilst the skin, flesh, and blood let them through. They
are allowed to fall (still invisible) on to a photographic plate,
when a picture like an ordinary permanent photograph is obtained
by their chemical action, or they may be made to exert their
phosphorescence-producing power on a glass plate covered with a thin
coating of a phosphorescent salt such as barium platino-cyanide, when
a temporary picture in light and shade is seen.
The rays discovered by Röntgen were known as the X-rays, because
their exact nature was unknown. Other rays studied in the electrified
vacuum-tubes are known as cathode rays or radiant corpuscles, and
others, again, as the Lenard rays.
It occurred to M. Henri Becquerel, as he himself tells us, to inquire
whether other phosphorescent bodies besides the glowing vacuum-tubes
of the electricians’ laboratory can emit penetrating rays like the
X-rays. I say ‘other phosphorescent bodies,’ for this power of
glowing without heat--of giving out, so to speak, cold light--is
known to be possessed by many mineral substances. It has become
familiar to the public in the form of ‘phosphorescent paint,’ which
contains sulphide of calcium, a substance which shines in the dark
after exposure to sunlight--that is to say, is phosphorescent. Other
sulphides and the minerals fluor-spar, apatite, some gems, and, in
fact, a whole list of substances have, under different conditions
of treatment, this power of phosphorescence or shining in the dark
without combustion or chemical change. All, however, require some
special treatment, such as exposure to sunlight or heat or pressure,
to elicit the phosphorescence, which is of short duration only.
Many of the compounds of a somewhat uncommon metallic element,
called uranium, used for giving a fine green colour to glass, are
phosphorescent substances, and it was, fortunately, one of them which
Henri Becquerel chose for experiment. Henri Becquerel is professor
in the Jardin des Plantes of Paris; his laboratory is a delightful
old-fashioned building, which had for me a special interest and
sanctity when, a few years ago, I visited him there, for, a hundred
years before, it was the dwelling-house of the great Cuvier. Here
Henri Becquerel’s father and grandfather--men renowned throughout
the world for their discoveries in mineralogy, electricity, and
light--had worked, and here he had himself gone almost daily from
his earliest childhood. Many an experiment bringing new knowledge
on the relations of light and electricity had Henri Becquerel
carried out in that quiet old-world place before the day on which,
about twelve years ago, he made the experimental inquiry, ‘Does
uranium give off penetrating rays like Röntgen rays?’ He wrapped a
photographic plate in black paper, and on it placed and left lying
there for twenty-four hours some uranium salt. He had placed a cross,
cut out in thin metallic copper, under the uranium powder, so as to
give some shape to the photographic print should one be produced.
It _was_ produced. Penetrating rays were given off by the uranium:
the black paper was penetrated, and the form of the copper cross was
printed on a dark ground (fig. 9). The copper was also penetrated to
some extent by the rays from the uranium, so that its image was not
left actually white. Only one step more remained before Becquerel
made his great discovery. It was known, as I stated just now, that
sulphide of calcium and similar substances _become_ phosphorescent
when exposed to sunlight, and lose this phosphorescence after a few
hours. Becquerel thought at first that perhaps the uranium salt
acquired its power similarly by exposure to light; but very soon,
by experimenting with uranium salt long kept in the dark, he found
that the emission of penetrating rays, giving photographic effects,
was produced spontaneously. The emission of rays by this particular
sample of uranium salt has shown no sign of diminution since this
discovery. The emission of penetrating rays by uranium was soon found
to be independent of its phosphorescence. Phosphorescent bodies,
as such, do not emit penetrating rays. Uranium compounds, whether
phosphorescent or not, emit and continue to emit, these penetrating
rays, capable of passing through black paper and in a less degree
through metallic copper. They do not derive this property from the
action of light or any other treatment. The emission of these rays
discovered by Becquerel is a new property of matter. It is called
‘radio-activity,’ and the rays are called Becquerel rays.
[Illustration: FIG. 9.--HENRI BECQUEREL’S DISCOVERY OF RADIO ACTIVITY.
Photographic print or skiagraph of a copper Maltese Cross
produced by uranium salt placed as a heap of powder on the
surface of black paper wrapped round a sensitive plate. Between
the paper and the uranium powder the flat copper cross was
interposed. The rays from the uranium salt have penetrated the
black paper, but have been intercepted to a large extent by the
copper cross--so that the sensitive silver plate is darkened all
about the cross--over an area corresponding to that of the heap
of uranium salt, but is left pale where the copper figure blocked
the path of the active rays given off by the uranium, partially
but not wholly. It was thus proved that the rays from the uranium
salt can pass through blackened paper and also though to a less
extent through a plate of copper.]
From this discovery by Becquerel to the detection and separation of
the new element radium is an easy step in thought, though one of
enormous labour and difficulty in practice. Professor Pierre Curie
(whose name I cannot mention without expressing the grief caused
to all men of science by the sad accident by which his life was
taken) and his wife, Madame Sklodowski Curie, incited by Becquerel’s
discovery, examined the ore called pitch-blende which is worked in
mines in Bohemia and is found also in Cornwall. It is the ore from
which all commercial uranium is extracted. The Curies found that
pitch-blende has a radio-activity four times more powerful than that
of metallic uranium itself. They at once conceived the idea that the
radio-activity of the uranium salts examined by Becquerel is due not
to the uranium itself, but to another element present with it in
variable quantities. This proved to be in part true. The refuse of
the first processes by which in the manufacturer’s works the uranium
is extracted from its ore, pitch-blende, was found to contain four
times more of the radio-active matter than does the pure uranium. By
a long series of fusions, solutions, and crystallizations the Curies
succeeded in ‘hunting down,’ as it were, the radio-active element.
The first step gave them a powder mixed with barium chloride, and
having 2,000 times the activity of the uranium in which Becquerel
first proved the existence of the new property--radio-activity. Then
step by step they purified it to a condition 10,000 times, then
to 100,000 times, and finally to the condition of a crystalline
salt having 1,800,000 times the activity of Becquerel’s sample of
uranium. The purification could go no further, but the extraordinary
minuteness of the quantity of the pure radio-active substance
obtained and the amount of labour and time expended in preparing it
may be judged of from the fact that of one ton of the pitch-blende
ore submitted to the process of purification only the hundredth of a
gram--the one-seventh of a grain--remained.
The amount of radium in pitch-blende is one ten-millionth per
cent.; rarer than gold in sea-water. The marvel of this story and
of all that follows consists largely in the skill and accuracy with
which our chemists and physicists have learnt to deal with such
infinitesimal quantities, and the gigantic theoretical results which
are securely posed on this pin-point of substantial matter.
The Curies at once determined that the minute quantity of colourless
crystals they had obtained was the chloride of a new metallic element
with the atomic weight 225, to which they gave the name radium. The
proof that radium is an element is given by its ‘sign-manual’--the
spectrum which it shows to the observer when in the incandescent
state. It consists of six bright lines and three fainter lines in the
visible part of the spectrum, and of three very intense lines in the
ultra-violet (invisible) part (fig. 10). A very minute quantity is
enough for this observation; the lines given by radium are caused by
no other known element in heaven or earth. They prove its title to be
entered on the roll-call of elements.
[Illustration: FIG. 10.
A diagram of the _visible_ lines of the spectrum of the elements
Radium and Helium--when rendered incandescent by electric
‘sparking’ in a glass tube: kindly prepared for this book by Mr.
Frederick Soddy of the University of Glasgow. The position of
the chief great lines of the solar spectrum are marked on the
lowest horizontal line. On the upper line the wave-lengths of
the rays occupying the position indicated, are given. The figure
72 means that the wave-length of the ray occupying this position
when refracted by the prism of the spectroscope is, as measured
from crest to crest of the undulation, seven hundred and twenty
millionths of a millimetre. It is generally written 720·0 µµ.
Lines exist at the ultra-violet end of the spectrum which can
be photographed but do not affect the eye--that is to say are
invisible. On the other hand the lines of the red end of the
spectrum do not produce a photographic effect. Consequently a
‘_photographed_’ spectrum such as that given in the next figure
(fig. 11) differs in the lines presented both at the red and the
violet ends from the _visible_ series of lines. The two (visible
and photographed spectra) agree only from wave-length 587·6 µµ to
wave-length 447·2 µµ.
The two spectra given in fig. 10 show how great is the difference
in the position and number of the bands of Radium and Helium--yet
as shown in the next figure (fig. 11) the ‘emanation’ from Radium
actually is transformed into Helium.]
The atomic weight was determined in the usual way by precipitating
the chlorine in a solution of radium chloride by means of silver.
None of the precious element was lost in the process, but the Curies
never had enough of it to venture on any attempt to prepare pure
metallic radium. This is a piece of extravagance no one has yet
dared to undertake. Altogether the Curies did not have more than
some four or five grains of chloride of radium to experiment with,
and the total amount prepared and now in the hands of scientific
men in various parts of the world probably does not amount to more
than sixty grains at most. When Professor Curie lectured on radium
four years ago at the Royal Institution in London he made use of a
small tube an inch long and of one-eighth bore, containing nearly
the whole of his precious store, wrenched by such determined labour
and consummate skill from tons of black shapeless pitch-blende. On
his return to Paris he was one day demonstrating in his lecture room
with this precious tube the properties of radium when it slipped from
his hands, broke, and scattered far and wide the most precious and
magical powder ever dreamed of by alchemist or artist of romance.
Every scrap of dust was immediately and carefully collected,
dissolved, and re-crystallized, and the disaster averted with a loss
of but a minute fraction of the invaluable product.
Thus, then, we have arrived at the discovery of radium--the
new element endowed in an intense form with the new property
‘radio-activity’ discovered by Becquerel. The wonder of this powder,
incessantly and without loss, under any and all conditions pouring
forth by virtue of its own intrinsic property powerful rays capable
of penetrating opaque bodies and of exciting phosphorescence and
acting on photographic plates, can perhaps be realized when we
reflect that it is as marvelous as though we should dig up a stone
which without external influence or change, continually poured forth
light or heat, manufacturing both in itself, and not only continuing
to do so without appreciable loss or change, but necessarily having
always done so for countless ages whilst sunk beyond the ken of man
in the bowels of the earth.
Wonderful as the story is, so far it is really simple and commonplace
compared with what yet remains to be told. I will only barely and
abruptly state the fact that radio-activity has been discovered
in other elements, some very rare, such as actinium and polonium;
others more abundant and already known, such as thorium and uranium,
though their radio-activity was not known until Becquerel’s
pioneer-discovery. It is a little strange and no doubt significant
that, after all, pure uranium is found to have a radio-activity of
its own and not to have been altogether usurping the rights of its
infinitesimal associate.
The wonders connected with radium really begin when the experimental
examination of the properties of a few grains is made. What I am
saying here is not a systematic, technical account of radium; so I
shall venture to relate some of the story as it impresses me.
Leaving aside for a moment what has been done in regard to the more
precise examination of the rays emitted by radium, the following
astonishing facts have been found out in regard to it: (1) If a glass
tube containing radium is much handled or kept in the waistcoat
pocket, it produces a destruction of the skin and flesh over a
small area--in fact, a sore place. (2) The smallest trace of radium
brought into a room where a charged electroscope is present, causes
the discharge of the electroscope. So powerful is this electrical
action of radium that a very sensitive electrometer can detect the
presence of a quantity of radium five hundred thousand times more
minute than that which can be detected by the spectroscope (that
is to say, by the spectroscopic examination of a flame in which
minute traces of radium are present). (3) Radium actually realizes
one of the properties of the hypothetical stone to which I compared
it, giving out light and heat. For it does give out heat which it
makes itself incessantly and without appreciable loss of substance
or energy (‘appreciable’ is here an important qualifying term). It
is also faintly self-luminous. Fairly sensitive thermometers show
that a few granules of radium salt have always a higher temperature
than that of surrounding bodies. Radium has been proved to give out
enough heat to melt rather more than its own weight of ice every
hour; enough heat in one hour to raise its own weight of water from
the freezing-point to the boiling-point. After a year and six weeks
a gram of radium has emitted enough heat to raise the temperature of
a thousand kilograms of water one degree. And this is always going
on. Even a small quantity of radium diffused through the earth will
suffice to keep up its temperature against all loss by radiation! If
the sun consists of a fraction of one per cent. of radium this will
account for and make good the heat that is annually lost by it.
This is a tremendous fact, upsetting all the calculations of
physicists as to the duration in past and future of the sun’s heat
and the temperature of the earth’s surface. The geologists and the
biologists have long contended that some thousand million years
must have passed during which the earth’s surface has presented
approximately the same conditions of temperature as at present,
in order to allow time for the evolution of living things and
the formation of the aqueous deposits of the earth’s crust. The
physicists, notably Professor Tait and Lord Kelvin, refused to allow
more than ten million years (which they subsequently increased to a
hundred million)--basing this estimate on the rate of cooling of a
sphere of the size and composition of the earth. They have assumed
that its material is self-cooling. But, as Huxley pointed out,
mathematics will not give a true result when applied to erroneous
data. It has now, within these last five years, become evident that
the earth’s material is _not_ self-cooling, but on the contrary
self-heating. And away go the restrictions imposed by physicists
on geological time. They now are willing to give us not merely a
thousand million years, but as many more as we want.
And now I have to mention the strangest of all the proceedings
of radium--a proceeding in which the other radio-active bodies,
actinium and thorium, resemble it. This proceeding has been entirely
Rutherford’s discovery in Canada, and his name must be always
associated with it. Radium (he discovered) is continually giving
off, apart from and in addition to the rectilinear darting rays of
Becquerel--an ‘emanation’--a gaseous ‘emanation.’ This ‘emanation’
is radio-active--that is, gives off Becquerel rays--and deposits
‘something’ upon bodies brought near the radium so that they become
radio-active, and remain so for a time after the radium is itself
removed. This emanation is always being formed by a radium salt, and
may be most easily collected by dissolving the salt in water, when
it comes away with a rush, as a gas. Sixty milligrams of bromide of
radium yielded to Ramsay and Soddy ·124 (or about one-eighth) of a
cubic millimetre of this gaseous emanation. What is it? It cannot be
destroyed or altered by heat or by chemical agents; it is a heavy
gas, having a molecular density of 100, and it can be condensed to
a liquid by exposing it to the great cold of liquid air. It gives
a peculiar spectrum of its own, and is probably a hitherto unknown
inert gas--a new element similar to argon. But this by no means
completes its history, even so far as experiments have as yet gone.
The radium emanation decays, changes its character altogether, and
loses half its radio-activity every four days. Precisely at the same
rate as it decays the specimen of radium salt from which it was
removed forms a new quantity of emanation, having just the amount of
radio-activity which has been lost by the old emanation. All is not
known about the decay of the emanation, but one thing is absolutely
certain, having first been discovered by Ramsay and Soddy and
subsequently confirmed by independent experiment by Madame Curie. It
is this: After being kept three or four days the emanation becomes,
in part at least, converted into helium--the light gas (second only
in the list of elements to hydrogen), the gas found twenty-five years
ago by Lockyer in the sun, and since obtained in some quantities from
rare radio-active minerals by Ramsay! The proof of the formation
of helium from the radium emanation is, of course, obtained by the
spectroscope, and its evidence is beyond assail (see fig. 11). Here,
then, is the partial conversion or decay of one element, radium,
through an intermediate stage into another. And not only that, but
if, as seems probable, the presence of helium indicates the previous
presence of radium, we have the evidence of enormous quantities of
radium in the sun, for we know helium is there in vast quantity. Not
only that, but inasmuch as helium has been discovered in most hot
springs and in various radio-active minerals in the earth, it may
be legitimately argued that no inconsiderable quantity of radium is
present in the earth. Indeed, it now seems probable that there is
enough radium in the sun to keep up its continual output of heat,
and enough in the earth to make good its loss of heat by radiation
into space, for an almost indefinite period. Other experiments of
a similar kind have rendered it practically certain that radium
itself is formed by a somewhat similar transformation of uranium, so
that our ideas as to the permanence and immutability on this globe
of the chemical elements are destroyed, and must give place to new
conceptions. It seems not improbable that the final product of the
radium emanation after the helium is removed is or becomes the metal
lead!
[Illustration: FIG. 11.
A { Tube containing
{ Helium gas derived
{ from the
{ mineral Clevelandite.
B { Tube of Radium
{ emanation, a
{ year old.
C { Tube of Hydrogen
{ gas for
{ comparison.
Photographs of the “spark” spectra of A, Helium as extracted
from the mineral Clevelandite of B, the Radium “emanation” after
a year’s enclosure in the tube used and of C of Hydrogen gas:
copied from the paper by Mr. F. Giesel in the _Berichte der
Deutschen Chemischen Gesellschaft_, vol. xxxix, part 10.
The three photographs are accurately super-imposed so as to show
the coincident lines.
The spectrum B of the tube containing radium emanation is the
one which we are comparing with the other two. When the radium
emanation was first enclosed there was only a small quantity of
helium developed in it, but after keeping for a year the quantity
has greatly increased. After five minutes “sparking” (passage of
the electric spark through the tube) the chief lines of helium
become evident but faint in intensity. The present photograph B
was obtained after forty minutes sparking, and one result of that
longer “sparking” has been that a minute quantity of water vapour
in the tube has been broken up--_so as to yield the hydrogen
spectrum_, which is accordingly seen accompanying the now strong
and brightly developed helium spectrum.
The lines of the spectrum B which correspond with those of
hydrogen are at once recognised by the juxtaposition (below)
of the pure Hydrogen spectrum from another tube--C: the lines
in B belonging to and indicating helium are also recognised
by comparison with the pure helium spectrum of the tube A
juxta-posed above. A very few of the lines in B must be due to
other minimal impurities as they are not present either in A or
C.
Thirteen lines of the helium spectrum are thus photographed and
recognised in the radium emanation.
The following lines are present in the photographic but invisible
spectrum of radium (not given in fig. 10), viz. at 381·47 µµ (the
strongest line in the radium spectrum) and at 364·96 (a strong
line).
In the photographic but invisible spectrum of helium there are
three very faint lines between wave-length 447·2 and 443·7
(appearing as two only in our photograph); a moderately strong
one at 438·8; others at 414·4, at 412·1, at 402·6, and 396·5;
a very strong one is present at 388·9, and a very faint one
at 381·9. All these are seen in the photograph A and also in
B. Special treatment and spectroscopes reveal four other very
faint lines in the helium spectrum--the one furthest in the
invisible direction (that is of highest refrangibility and lowest
wave-length) being placed at 318·6 (Soddy).]
It must be obvious from all the foregoing that radium is very slowly,
but none the less surely, destroying itself. There is a definite
loss of particles which, in the course of time, must lead to the
destruction of the radium, and it would seem that the large new
credit on the bank of time given to biologists in consequence of
its discovery has a definite, if remote, limit. With the quantities
of radium at present available for experiment, the amount of loss
of particles is so small, and the rate so slow, that it cannot be
weighed by the most delicate balance. Nevertheless it has been
calculated that radium will transform half of itself in about fifteen
hundred years, and unless it were being produced in some way all of
the radium now in existence would disappear much too soon to make
it an important geological factor in the maintenance of the earth’s
temperature. As a reply to this depreciatory statement we have the
discovery by Rutherford and others that radium is continually being
formed afresh, and from that particular element in connection with
which it was discovered--namely, uranium. Hypotheses and experiments
as to the details of this process are at this moment in full swing,
and results of a momentous kind, involving the building-up of an
element with high atomic weight by the interaction of elements with
a lower atomic weight, are thought by some physicists to be not
improbable in the immediate future.
The delicate electric test for radio-activity has been largely
applied in the last few years to all sorts and conditions of matter.
As a result it appears that the radium emanation is always present in
our atmosphere; that the air in caves is especially rich in it, as
are underground waters. Tin-foil, glass, silver, zinc, lead, copper,
platinum and aluminium are, all of them, slightly radio-active. The
question has been raised whether this widespread radio-activity
is due to the wide dissemination of infinitesimal quantities of
strong radio-active elements, or whether it is the natural intrinsic
property of all matter to emit Becquerel rays. This is the immediate
subject of research.
Over and above the more simply appreciable facts which I have thus
narrated, there comes the necessary and difficult inquiry, What does
it all mean? What _are_ the Becquerel rays of radio-activity? What
must we conceive to be the structure and mechanism of the atoms of
radium and allied elements, which can not only pour forth ceaseless
streams of intrinsic energy from their own isolated substance, but
are perpetually, though in infinitesimal proportions, changing their
elemental nature spontaneously, so as to give rise to other atoms
which we recognise as other elements?
I cannot venture as an expositor into this field. It belongs to that
wonderful group of men, the modern physicists, who with an almost
weird power of visual imagination combine the great instrument of
exact statement and mental manipulation called mathematics, and
possess an ingenuity and delicacy in appropriate experiment which
must fill all who even partially follow their triumphant handling of
Nature with reverence and admiration. Such men now or recently among
us are Kelvin, Clerk Maxwell, Crookes, Rayleigh, and J. J. Thomson.
Becquerel showed early in his study of the rays emitted by radium
that some of them could be bent out of their straight path by making
them pass between the poles of a powerful electro-magnet. In this
way have finally been distinguished three classes of rays given off
by radium: (1) the _alpha_ rays, which are only slightly bent, and
have little penetrative power; (2) the _beta_ rays, easily bent in
a direction opposite to that in which the alpha rays bend, and of
considerable penetrative power; (3) the _gamma_ rays, which are
absolutely unbendable by the strongest magnetic force, and have an
extraordinary penetrative power, producing a photographic effect
through a foot thickness of solid iron.
The _alpha_ rays are shown to be streams of tiny bodies positively
electrified, such as are given off by gas flames and red-hot metals.
The particles have about twice the mass of a hydrogen atom, and they
fly off with a velocity of 20,000 miles a second; that is, 40,000
times greater than that of a rifle bullet. The heat produced by
radium is ascribed to the impact of these particles of the alpha
rays.
The _beta_ rays are streams of corpuscles similar to those given
off by the cathode in a vacuum tube. They are charged with negative
electricity and travel at the velocity of 100,000 miles a second.
They are far more minute than the alpha particles. Their mass is
equal to the one-thousandth of a hydrogen atom. They produce the
major part of the photographic and phosphorescent effects of the
radium rays.
The _gamma_ rays are apparently the same, or nearly the same, thing
as the X-rays of Röntgen. They are probably not particles at all,
but pulses or waves in the ether set up during the ejection of the
corpuscles which constitute the beta rays. They produce the same
effects in a much smaller degree as do the beta rays, but are more
penetrating.
The kind of conceptions to which these and like discoveries have led
the modern physicist in regard to the character of that supposed
unbreakable body--the chemical atom--the simple and unaffected
friend of our youth--are truly astounding. Nevertheless, they are
not destructive of our previous conceptions, but rather elaborations
and developments of the simpler views, introducing the notion of
structure and mechanism, agitated and whirling with tremendous force,
into what we formerly conceived of as homogeneous or simply built-up
particles, the earlier conception being not so much a positive
assertion of simplicity as a non-committal expectant formula awaiting
the progress of knowledge and the revelations which are now in our
hands.
As I have already stated, the attempt to show in detail how the
marvellous properties of radium and radio-activity in general are
thus capable of a pictorial or structural representation is beyond
the limits of the present essay; but the fact that such speculations
furnish a scheme into which the observed phenomena can be fitted is
what we may take on the authority of the physicists and chemists of
our day.
Intimately connected with all the work which has been done in the
past twenty-five years in the nature and possible transformations
of atoms is the great series of investigations and speculations on
astral chemistry and the development of the chemical elements which
we owe to the unremitting labour during this period of Sir Norman
Lockyer.
_Wireless telegraphy._--Of great importance has been the whole
progress in the theory and practical handling of electrical
phenomena of late years. The discovery of the Hertzian waves and
their application to wireless telegraphy is a feature of this
period, though I may remind some of those who have been impressed
by these discoveries that the mere fact of electrical action at a
distance is that which hundreds of years ago gave to electricity
its name. The power which we have gained of making an instrument
oscillate in accordance with a predetermined code of signalling,
although detached and a thousand miles distant, does not really
lend any new support[15] to the notion that the old-time beliefs of
thought-transference and second sight are more than illusions based
on incomplete observation and imperfect reasoning. For the important
factors in such human intercourse--namely, a signalling-instrument
and a code of signals--have not been discovered, as yet in the
structure of the human body, and have to be consciously devised and
manufactured by man in the only examples of thought-transference
over long distances at present discovered or laid bare to experiment
and observation.
_High and low temperatures._--The past quarter of a century has
witnessed a great development and application of the methods of
producing both very low and very high temperatures. Sir James Dewar,
by improved apparatus, has produced liquid hydrogen and a fall of
temperature probably reaching to the absolute zero. A number of
applications of extremely low temperatures to research in various
directions has been rendered possible by the facility with which
they may now be produced. Similarly high temperatures have been
employed in continuation of the earlier work of Deville, and others
by Moissan, the distinguished French chemist.
_Progress in Chemistry._--In chemistry generally the theoretical
tendency guiding a great deal of work has been the completion and
verification of the ‘periodic law’ of Mendeléeff; and, on the other
hand, the search by physical agents such as light and electricity for
evidence as to the arrangement of atoms in the molecules of the most
diverse chemical compounds. The study of ‘valency’ and its outcome,
stereo-chemistry, have been the special lines in which chemistry has
advanced. As a matter of course hundreds, if not thousands, of new
chemical bodies have been produced in the laboratory of greater or
less theoretical interest. The discovery of the greatest practical
and industrial importance in this connection is the production of
indigo by synthetical processes, first by laboratory and then by
factory methods, so as to compete successfully with the natural
product. Von Baeyer and Heumann are the names associated with this
remarkable achievement, which has necessarily dislocated a large
industry which derived its raw material from British India.
[Illustration: FIG. 12.
This figure should be examined with a magnifying glass. It is
a direct reproduction of a photograph of a detached nebula
and surrounding stars in Cygnus by Dr. Max Wolf of Heidelberg
(reproduced by permission from the Monthly Notices of the Royal
Astronomical Society, vol. lxiv, Plate 18, p. 839, q.v.). The
exposure was four hours on July 10th, 1904, with a camera the
lenses of which have a diameter of sixteen inches. The picture is
enlarged so that the apparent diameter of the Sun or Moon would
be about 1⅓ inch on the same scale (one minute, or sixtieth of a
degree, equals one millimetre).
The “apparent diameter” of the sun or moon is about one in 115:
that is to say that a covering disc of any size you like can be
made exactly to coincide with and “cover” the disc of the sun
or moon provided that you place it at a distance from the eye
equal to 115 times its own diameter--thus a disc of an inch in
diameter (say a halfpenny) will just “cover” the sun or moon if
placed at a distance from the eye of a little less than ten feet,
a threepenny piece will cover it at about six feet, and a disc of
somewhat less than half that size when held at arm’s length.
The nebula (on the horizontal A A) is seen surrounded by a dark
space--at the end of a long dark lane or “rift” which reminds us
of the track left by a snowball rolled along in the snow. Has the
nebula in some mysterious way swept up the stars in its journey
through space? We cannot at present either affirm or deny such
interpretations.
One or two of the brightest of the surrounding stars _might_ just
be seen by an acute eye unaided by a telescope--but no more. The
best existing telescopes would show _only_ the large nebular
body on the line A A, and the larger white spots; the finest
dust-like particles are stars of which the existence is only
demonstrated by prolonged photographic exposures such as this,
with a lens which focuses its image on to the _dry_ plate. The
old “wet-plate” would not remain wet sufficiently long to “take”
the picture.
It should be borne in mind in looking at this picture that each
of the minutest white spots is probably of at least the same size
as our own sun: further, that each is probably surrounded by a
planetary system similar to our own.]
_Astronomy._--A biologist may well refuse to offer any remarks on
his own authority in regard to this earliest and grandest of all the
sciences. I will therefore at once say that my friend the Savilian
Professor of Astronomy in Oxford has turned my thoughts in the right
direction in regard to this subject. There is no doubt that there has
been an immense ‘revival’ in astronomy since 1881; it has developed
in every direction. The invention of the ‘dry plate,’ which has
made it possible to apply photography freely in all astronomical
work, is the chief cause of its great expansion. Photography was
applied to astronomical work before 1881, but only with difficulty
and haltingly. It was the dry-plate (see Fig. 12) which made long
exposures possible, and thus enabled astronomers to obtain regular
records of faintly luminous objects such as nebulæ and star-spectra.
Roughly speaking, the number of stars visible to the naked eye may
be stated as eight thousand: this is raised by the use of our best
telescopes to some hundred million. But the number which can be
photographed is indefinite and depends on length of exposure: some
thousands of millions can certainly be so recorded.
The serious practical proposal to ‘chart the sky’ by means of
photography certainly dates from this side of 1881. The Paris
Conference of 1887, which made an international scheme for sharing
the sky among eighteen observatories (still busy with the work, and
producing excellent results), originated with photographs of the
comet of 1882, taken at the Cape Observatory.
Professor Pickering, of Harvard, did not join this co-operative
scheme, but has gradually devised methods of charting the sky very
rapidly, so that he has at Harvard records of the whole sky many
times over, and when new objects are discovered he can trace their
history _backwards_ for more than a dozen years by reference to his
plates. This is a wonderful new method, a mode of keeping record of
present movements and changes which promises much for the future of
astronomy. By the photographic method hundreds of new variable stars
and other interesting objects have been discovered. New planets have
been detected by the hundred. Up to 1881 two hundred and twenty were
known. In 1881 only one was found; namely, Stephania, being No. 220,
discovered on May 19. Now a score at least are discovered every year.
Over 500 are now known. One of these--Eros--(No. 433) is particularly
interesting, since it is nearer to the sun than is Mars, and gives
a splendid opportunity for fixing with increased accuracy the sun’s
distance from the earth. Two new satellites to Saturn and two to
Jupiter have been discovered by photography (besides one to Jupiter
in 1892 by the visual telescope of the Lick Observatory). One of the
new satellites of Saturn goes round that planet the _wrong way_, thus
calling for a fundamental revision of our ideas of the origin of the
solar system.
The introduction of photography has made an immense difference in
spectroscopic work. The spectra of the stars have been readily mapped
out and classified, and now the motions in the line of sight of
faint stars can be determined. This ‘motion in the line of sight,’
which was discernible but scarcely measurable with accuracy before,
now provides one of the most refined methods in astronomy for
ascertaining the dimensions and motions of the universe. It gives us
velocities in miles per second instead of in an angular unit to be
interpreted by a very imperfect knowledge of the star’s distance.
The method, initiated practically by Huggins thirteen years before,
was in 1881 regarded by many astronomers as a curiosity. Visual
observations were begun at Greenwich in 1875, but were found to be
affected by instrumental errors. The introduction of dry plates, and
their application by Vogel in 1887, was the beginning of general
use of the method, and line-of-sight work is now a vast department
of astronomical industry. Among other by-products of the method are
the ‘spectroscopic doubles,’ stars which we know to be double, and
of which we can determine the period of revolution, though we cannot
separate them visually by the greatest telescope.
Work on the sun has been entirely revolutionised by the use
of photography. The last decade has seen the invention of the
spectro-heliograph--which simply means that astronomers can now study
_in detail_ portions of the sun of which they could previously only
get a bare indication.
More of the same story could be related, but enough has been said to
show how full of life and progress is this most ancient and imposing
of all sciences.
A minor though very important influence in the progress of astronomy
has been the provision, by the expenditure of great wealth in
America, of great telescopes and equipments.
In 1877 Sir George Darwin started a line of mathematical research
which has been very fruitful and is of great future promise for
astronomy. As recently as last April, at the Royal Astronomical
Society, two important papers were read--one by Mr. Cowell and the
other by Mr. Stratton--which have their roots in Sir George Darwin’s
work. The former was led to suggest that the day is lengthening ten
times as rapidly as had been supposed, and the latter showed that in
all probability the planets had all turned upside down since their
birth.
And yet M. Brunetière and his friends wish us to believe that science
is bankrupt and has no new things in store for humanity.
_Geology._--In the field of geological research the main feature
in the past twenty-five years has been the increasing acceptance
of the evolutionary as contrasted with the uniformitarian view of
geological phenomena. The great work of Suess, ‘Das Antlitz der
Erde,’ is undoubtedly the most important contribution to physical
geology within the period. The first volume appeared in 1885, and the
impetus which it has given to the science may be judged of by the
epithet applied to the views for which Suess is responsible--‘the
New Geology.’ Suess attempts to trace the orderly sequence of the
principal changes in the earth’s crust since it first began to form.
He strongly opposes the old theory of elevation, and accounts for the
movements as due to differential collapse of the crust, accompanied
by folding due to tangential stress. Among special results gained by
geologists in the period we survey may be cited new views as to the
origin of the crystalline schists, favouring a return to something
like the hypogene origin advocated by Lyell; the facts as to deep-sea
deposits, now in course of formation, embodied in the ‘Challenger’
reports on that subject: the increasing discrimination and tracking
of those minor divisions of strata called ‘zones’; the assignment of
the Olenellus fauna of Cambrian age to a position earlier than that
of the Paradoxides fauna; the discovery of Radiolaria in palæozoic
rocks by special methods of examination, and the recognition of
Graptolites as indices of geological horizons in lower palæozoic
beds. Glacially eroded rocks in boulder-clays of permo-carboniferous
age have been recognised in many parts of the world (_e.g._,
Australia and South Africa), and thus the view put forward by W. T.
Blanford as to the occurrence of the same phenomena in conglomerates
of this age in India is confirmed. Eozoon is finally abandoned as
owing its structure to an organism. The oldest fossiliferous beds
known to us are still far from the beginning of life. They contain
a highly developed and varied animal fauna--and something like the
whole of the older moiety of rocks of aqueous origin have failed as
yet to present us with any remains of the animals or plants which
must have inhabited the seas which deposited them. The boring of a
coral reef initiated by Professor Sollas at the Nottingham meeting
of the British Association in 1893 was successfully carried out,
and a depth of 1,114½ feet reached. Information of great value to
geologists was thus obtained.
[Illustration: FIG. 13.
The Freshwater Jelly-fish of Regent’s Park (_Limnocodium
Sowerbii_) magnified five times linear.
It was discovered in the tropical lily tank of the Botanical
Gardens in June, 1880, and swarmed in great numbers year after
year--then suddenly disappeared. It has since been found in
similar tanks in Sheffield, Lyons, and Munich. Only male
specimens were discovered, and the native home of the wonderful
visitor is still unknown.]
[Illustration: FIG. 14.
The minute polyp attached to the rootlets of water-plants--from
which the Jelly-fish _Limnocodium_ was found to be ‘budded off.’]
[Illustration: FIG. 15.
One of the peculiar sense-organs from the edge of the swimming
disc of _Limnocodium_. C, cavity of capsule; EC, ectoderm; EN,
endoderm. Sense-organs of identical structure are found in
the Freshwater Jelly-fish of Lake Tanganyika and in no other
jelly-fish.]
_Animal and Vegetable Morphography._--Were I to attempt to give an
account of the new kinds of animals and plants discovered since 1881,
I should have to offer a bare catalogue, for space would not allow
me to explain the interest attaching to each. Explorers have been
busy in all parts of the world--in Central Africa, in the Antarctic,
in remote parts of China, in Patagonia and Australia, and on the
floor of the ocean as well as in caverns, on mountain tops, and
in great lakes and rivers. We have learnt much that is new as to
distribution; countless new forms have been discovered, and careful
anatomical and microscopical study conducted on specimens sent home
to our laboratories. I cannot refrain from calling to mind the
discovery of the eggs of the Australian duck-mole and hedgehog; the
freshwater jelly-fish (figs. 13, 14, and 15) of Regent’s Park, the
African lakes (fig. 16) and the Delaware River; the marsupial mole of
Central Australia; the okapi (figs. 17, 18, and 19); the breeding and
transformations of the common eel (fig. 20); the young and adult of
the mud-fishes of Australia, Africa, and South America; the fishes of
the Nile and Congo; the gill-bearing earth-worms and mud-worms; the
various forms of the caterpillar-like _Peripatus_; strange deep-sea
fishes, polyps and sponges.
[Illustration: FIG. 16.
The Freshwater Jelly-fish of Lake Tanganyika (_Limnocnida
Tanganyicae_), magnified five times linear. Since its discovery
in Tanganyika it has been found also in the Lake Victoria Nyanza
and in pools in the Upper Niger basin.]
[Illustration: FIG. 17.
The Giraffe-like animal called the Okapi, discovered by Sir Harry
Johnston in the Congo Forest. Photograph of the skin of a female
sent home by him in 1901, and now mounted and exhibited in the
Natural History Museum.]
[Illustration: FIG. 18.
Two “bandoliers” cut by the natives from the striped part of
the skin (the haunches) and at first supposed to be bits of the
hide of a new kind of Zebra. These were sent home by Sir Harry
Johnston in 1900.]
The main result of a good deal of such investigation is measured by
our increased knowledge of the pedigree of organisms, what used to
be called ‘classification.’ The anatomical study by the Australian
professors, Hill and Wilson, of the teeth and the fœtus of the
Australian group of pouched mammals--the marsupials--has entirely
upset previous notions, to the effect that these are a primitive
group, and has shown that their possession of only one replacing
tooth is a retention of one out of many such teeth (the germs of
which are present), as in placental mammals; and further that many of
these marsupials have the nourishing outgrowth of the fœtus called
the placenta fairly well developed, so that they must be regarded
as a degenerate side-branch of the placental mammals, and not as
primitive forerunners of that dominant series.
[Illustration: FIG. 19.
Photograph of the skull of a male Okapi--showing the paired boney
horn-cores--similar to those of the Giraffe, but connected with
the frontal bones and not with the parietals as the horn-cores of
Giraffes are.]
[Illustration: FIG. 20.
Drawings by Professor Grassi, of Rome, of the young of the common
Eel and its metamorphosis. All of the natural size. The uppermost
figure represents a transparent glass-like creature--which was
known as a rare “find” to marine naturalists, and received the
name _Leptocephalus_. Really it lives in vast numbers in great
depths of the sea--five hundred fathoms and more. It is hatched
here from the eggs of the common Eel which descends from the
ponds, lakes, and rivers of Europe in order to breed in these
great depths. The gradual change of the _Leptocephalus_ into a
young Eel or “Elver” is shown, and was discovered by Grassi. The
young Eels leave the great depth of the ocean and ascend the
rivers in immense shoals of many hundred thousand individuals,
and wriggle their way up banks and rocks into the small streams
and pools of the continent.
The above figures were published by Professor Grassi in November
1896, in the _Quarterly Journal of Microscopical Science_, edited
by E. Ray Lankester and published by Churchill & Sons.]
Speculations as to the ancestral connection of the great group of
vertebrates with other great groups have been varied and ingenious;
but most naturalists are now inclined to the view that it is a
mistake to assume any such connection in the case of vertebrates of
a more definite character than we admit in the case of starfishes,
shell-fish, and insects. All these groups are ultimately connected
by very simple, remote, and not by proximate ancestors, with one
another and with the ancestors of vertebrates.
[Illustration: FIG. 21.
The unicellular parasite _Benedenia_, from the gut of the
common Poulp or Octopus. 1 is the normal male individual; 2 and
3 show stages in the production of spermatozoa on its surface
by budding; 4, 5 and 6 show a female parasite with spermatozoa
approaching it.]
[Illustration: FIG. 22.
Production of spermatozoa on the surface of the unicellular
parasite _Coccidium oviforme_, from the Rabbit’s intestines.]
The origin of the limbs of vertebrates is now generally agreed to be
correctly indicated in the Thatcher-Mivart-Balfour theory to the
effect that they are derived from a pair of continuous lateral fins,
in fish-like ancestors, similar in every way to the continuous median
dorsal fin of fishes.
[Illustration: FIG. 23.
Spermatozoa (often called “microgametes”) of the unicellular
parasite _Echinospora_ found in the gut of the small Centipede
_Lithobius mutabilis_.]
The discovery of the formation of true spermatozoa by simple
unicellular animals of the group Protozoa is a startling thing, for
it had always been supposed that these peculiar reproductive elements
were only formed by multicellular organisms (figs. 21, 22, and 23).
They have been discovered in some of the gregarina-like animalcules,
the _Coccidia_, and also in the blood-parasites.
Among plants one of the most important discoveries relates to these
same reproductive elements, the spermatozoa, which by botanists are
called antherozoids. A great difference between the whole higher
series of plants, the flowering plants or phanerogams, and the
cryptogams or lower plants, including ferns, mosses, and algae,
was held to be that the latter produce vibratile spermatozoa like
those of animals which swim in liquid and fertilise the motionless
egg-cell of the plant. Two Japanese botanists (and the origin of this
discovery from Japan, from the University of Tokio, in itself marks
an era in the history of science), Hirase and Ikeno, astonished the
botanical world fifteen years ago by showing that motile antherozoids
or spermatozoa are produced by two gymnosperms, the ging-ko tree (or
_Salisburya_) and the cycads (fig. 24). The pollen-tube, which is
the fertilising agent in all other phanerogams, develops in these
cone-bearing trees, beautiful motile spermatozoa, which swim in a
cup of liquid provided for them in connection with the ovules. Thus
a great distinction between phanerogams and cryptogams was broken
down, and the actual nature of the pollen-tube as a potential parent
of spermatozoids demonstrated.
[Illustration: FIG. 24.
Spermatozoa (antherozoids) of _Cycas revoluta_, seen from the
side and from above. The spermatozoon is spherical, carrying a
spiral band of minute vibratile hairs (_cilia_) by which it is
propelled.]
When we come to the results of the digging out and study of extinct
plants and animals, the most remarkable results of all in regard
to the affinities and pedigree of organisms have been obtained.
Among plants the transition between cryptogams and phanerogams
has been practically bridged over by the discovery that certain
fern-like plants of the Coal Measures--the _Cycadofilices_, supposed
to be true ferns, are really seed-bearing plants and not ferns at
all, but phanerogams of a primitive type, allied to the cycads
and gymnosperms. They have been re-christened _Pteridosperms_ by
Scott, who, together with F. Oliver and Seward, has been the chief
discoverer in this most interesting field.
[Illustration: FIG. 25.
The gigantic three-horned Reptile, _Triceratops_, as large as an
Elephant, found in Jurassic strata in North America. A model of
the skeleton may be seen in the Natural History Museum in London.]
By their fossil remains whole series of new genera of extinct mammals
have been traced through the tertiary strata of North America and
their genetic connections established; and from yet older strata of
the same prolific source we have almost complete knowledge of several
genera of huge extinct _Dinosauria_ of great variety of form and
habit (fig. 25).
[Illustration: FIG. 26.
Photograph of the skeleton of a large carnivorous Reptile
from Triassic strata in North Russia, discovered by Professor
Amalitzky and named by him, _Inostransevia_. The head alone is
two feet in length.]
[Illustration: FIG. 27.
Photographs of completed models of the Devonian fish
_Drepanaspis_, from Devonian slates of North Germany, worked out
by Professor Traquair. The models are in the Natural History
Museum, London.]
[Illustration: FIG. 28.
The oldest fossil fish known--discovered in the Upper Silurian
strata of Scotland, and named _Birkenia_ by Professor Traquair.]
The discoveries by Seeley at the Cape, and by Amalitzky in
North Russia of identical genera of Triassic reptiles, which in
many respects resemble the Mammalia and constitute the group
_Theromorpha_, is also a prominent feature in the palæontology
of the past twenty-five years (fig. 26). Nor must we forget the
extraordinary Devonian and Silurian fishes discovered and described
by Professor Traquair (figs. 27 and 28). The most important discovery
of the kind of late years has been that of the Upper Eocene and
Miocene Mammals of the Egyptian Fayum, excavated by the Egyptian
Geological Survey and by Dr. Andrews of the Natural History Museum,
who has described and figured the remains. They include a huge
four-horned animal as big as a rhinoceros, but quite peculiar in
its characters--the _Arisinoïtherium_--and the ancestors of the
elephants, a group which was abundant in Miocene and Pliocene times
in Europe and Asia, and in still later times in America, and
survives at the present day in its representatives the African
and Indian elephant. One of the European extinct elephants--the
_Tetrabelodon_--had, we have long known, an immensely long lower
jaw with large chisel-shaped terminal teeth. It had been suggested
by me that the modern elephant’s trunk must have been derived
from the soft upper jaw and nasal area, which rested on this
elongated lower jaw, by the shortening (in the course of natural
selection and modification by descent) of this long lower jaw, to
the present small dimensions of the elephant’s lower jaw, and the
consequent down-dropping of the unshortened upper jaw and lips,
which thus become the proboscis. Dr. Andrews has described from
Egypt and placed in the Museum in London specimens of two new
genera--one _Palæomastodon_, in which there is a long, powerful
jaw, an elongated face, and an increased number of molar teeth (see
figs. 29 and 30); the second, _Meritherium_ (fig. 31), an animal
with a hippopotamus-like head, comparatively minute tusks, and a
well-developed complement of incisor, canine, and molar teeth, like a
typical ungulate mammal. Undoubtedly we have in these two forms the
indications of the steps by which the elephants have been evolved
from ordinary-looking pig-like creatures of moderate size, devoid of
trunk or tusks. Other remains belonging to this great mid-African
Eocene fauna indicate that not only the Elephants but the Sirenia
(the Dugong and Manatee) took their origin in this area. Amongst them
are also gigantic forms of Hyrax, like the little Syrian coney and
many other new mammals and reptiles.
[Illustration: FIG. 29.
Photograph of a complete model of the skull and lower jaw of the
ancestral elephant, _Palæomastodon_, discovered by Dr. Andrews
in the Upper Eocene of the Fayum Desert, Egypt, and modelled
and restored under his direction in the Natural History Museum,
London. The comparatively short trunk or snout rested on the
broad front teeth of the long lower jaw. The face is elongated,
and the cheek-teeth are numerous.]
[Illustration: FIG. 30.
Photograph of the lower face of the skull of a specimen of
_Palæomastodon_ brought from Egypt in April, 1906, by Dr.
Andrews, and now in the Natural History Museum, London. The
six characteristic cheek-teeth on each side, and the pair of
sabre-like tusks in front, are well seen.]
[Illustration: FIG. 31.
Drawing of the skull and lower jaw of the _Meritherium_,
discovered by Dr. Andrews in the Upper Eocene of the Fayum
Desert. The shape of the skull and proportions of face and jaw
are like those of an ordinary hoofed mammal such as the pig;
but the cheek-teeth are similar to those of the _Mastodon_, and
whilst the full complement of teeth is present in the front of
the upper jaw, we can distinguish the big tusk-like incisor which
alone survives on each side in _Palæomastodon_, _Mastodon_, and
the elephants, as the great pair of tusks.]
Another great area of exploration and source of new things has been
the southern part of Argentina and Patagonia, where Ameghino, Moreno,
and Scott of Princeton have brought to light a wonderful series of
extinct ant-eaters, armadilloes, huge sloths, and strange ungulates,
reaching back into early Tertiary times. But most remarkable has
been the discovery in this area of remains which indicate a former
connection with the Australian land surface. This connection is
suggested by the discovery in the Santa Cruz strata, considered to be
of early Tertiary date, of remains of a huge horned tortoise which is
generically identical with one found fossil in the Australian area of
later date, and known as _Miolania_. In the same wonderful area we
have the discovery in a cave of the fresh bones, hairy skin, and dung
of animals supposed to be extinct, viz., the giant sloth, _Mylodon_,
and the peculiar horse, _Onohippidium_. These remains seem to belong
to survivors from the last submergence of this strangely mobile
land-surface, and it is not improbable that some individuals of this
‘extinct’ fauna are still living in Patagonia. The region is still
unexplored and those who set out to examine it have, by some strange
fatality, hitherto failed to carry out the professed purpose of their
expeditions.
I cannot quit this immense field of gathered fact and growing
generalisation without alluding to the study of animal embryology
and the germ-layer theory, which has to some extent been superseded
by the study of embryonic cell-lineage, so well pursued by some
American microscopists. The great generalisation of the study
of the germ-layers and their formation seems to be now firmly
established--namely, that the earliest multicellular animals were
possessed of one structural cavity, the enteron, surrounded by a
double layer of cells, the ectoderm and endoderm. These _Enterocœla_
or _Cœlentera_ gave rise to forms having a second great body-cavity,
the cœlom, which originated not as a split between the two layers, as
was supposed twenty-five years ago by Haeckel and Gegenbaur and their
pupils, but by a pouching of the enteron to form one or more cavities
in which the reproductive cells should develop--pouchings which
became nipped off from the cavity of their origin, and formed thus
the independent cœlom. The animals so provided are the _Cœlomocœla_
(as opposed to the _Enterocœla_), and comprise all animals above
the polyps, jelly-fish, corals, and sea-anemones. It has been
established in these twenty-five years that the cœlom is a definite
structural unit of the higher groups, and that outgrowths from it to
the exterior (cœlomoducts) form the genital passages, and may become
renal excretory organs also. The vascular system has not, as it was
formerly supposed to have, any connection of origin with the cœlom,
but is independent of it, in origin and development, as also are
the primitive and superficial renal tubes known as nephridia. These
general statements seem to me to cover the most important advance
in the general morphology of animals which we owe to embryological
research in the past quarter of a century.[16]
Before leaving the subject of animal morphology I must apologise
for my inability to give space and time to a consideration of the
growing and important science of anthropology, which ranges from
the history of human institutions and language to the earliest
prehistoric bones and implements. Let me therefore note here the
discovery of the cranial dome of _Pithecanthropus_ in a river gravel
in Java--undoubtedly the most ape-like of human remains, and of great
age (see figs. 1 and 2); and, further, the Eoliths of Prestwich (see
figs. 3 and 4), in the human authorship of which I am inclined to
believe, though I should be sorry to say the same of all the broken
flints to which the name ‘Eolith’ has been applied. The systematic
investigation and record of savage races have taken on a new and
scientific character. Such work as Baldwin Spencer’s and Haddon’s in
Australasia furnish examples of what is being done in this way.
[Illustration: FIG. 32.
_Bacillus radicola_, the parasite which infests the roots of
leguminous plants and causes the growth of nodules whilst
assisting the plant in the assimilation of nitrogen: (_a_)
Nodule of the roots of the common Lupine, natural size; (_b_)
longitudinal section through a Lupine root and nodule; (_c_)
a single cell from a Lupine nodule showing the bacteria or
bacilli, as black particles in the protoplasm, magnified 600
diameters; (_d_) bacilli from the root nodule of the Lupine;
(_e_) triangular forms of the bacillus from the root nodules of
the Vetch; (_f_) oval forms from the root nodules of the Lupine;
(_d e f_) are magnified 1,500 diameters.]
_Physiology of Plants and Animals._--Since I have not space to do
more than pick out the most important advances in each subject for
brief mention, I must signalize in regard to the physiology of plants
the better understanding of the function of leaf-green or chlorophyll
due to Pringsheim and to the Russian Timiriaseff, the new facts as to
the activity of stomata in transpiration discovered by Horace Brown,
and the fixation of free nitrogen by living organisms in the soil
and by organisms (_Bacillus radicola_) parasitic in the rootlets of
leguminous plants (see fig. 32), which thus benefit by a supply of
nitrogenous compounds which they can assimilate.
Great progress in the knowledge of the chemistry of the living
cells or protoplasm of both plants and animals has been made by the
discovery of the fact that ferments or enzymes are not only secreted
externally by cells, but exist active and preformed _inside_ cells.
Büchner’s final conquest of the secret of the yeast-cell by heroic
mechanical methods--the actual grinding to powder of these already
very minute bodies--first established this, and now successive
discoveries of intracellular ferments have led to the conclusion
that it is probable that the cell respires by means of a respiratory
‘oxydase,’ builds up new compounds and destroys existing ones,
contracts and accomplishes its own internal life by ferments. Life
thus (from the chemical point of view) becomes a chain of ferment
actions. Another most significant advance in animal physiology has
been the sequel (as it were) of Bernard’s discovery of the formation
of glycogen in the liver, a substance not to be excreted, but to be
taken up by the blood and lymph, and in many ways more important
than the more obvious formation of bile which is thrown out of the
gland into the alimentary canal. It has been discovered that many
glands, such as the kidney and pancreas and the ductless glands, the
suprarenals, thyroid, and others, secrete indispensable products into
the blood and lymph. Hence myxœdema, exophthalmic goitre, Addison’s
disease, and other disorders have been traced to a deficiency or
excess of internal secretions from glands formerly regarded as
interesting but unimportant vestigial structures. From these glands
have in consequence been extracted remarkable substances on which
their peculiar activity depends. From the suprarenals a substance
has been extracted which causes activity of all those structures
which the sympathetic nerve-system can excite to action; the thyroid
yields a substance which influences the growth of the skin, hair,
bones, &c.; the pituitary gland, an extract which is a specific
urinary stimulant. Quite lately the mammalian ovary has been shown by
Starling to yield a secretion which influences the state of nutrition
of the uterus and mammæ. A great deal more might be said here on
topics such as these--topics of almost infinite importance; but the
fact is that the mere enumeration of the most important lines of
progress in any one science would occupy many pages.
[Illustration: FIG. 33.
The continuity of the protoplasm of neighbouring vegetable cells,
by means of threads which perforate the cell-walls. Drawing
(_after_ Gardiner) of cells from the pulvinus of _Robinia_.]
Nerve-physiology has made immensely important advances. There is
now good evidence that all excitation of one group of nerve-centres
is accompanied by the _concurrent inhibition_ of a whole series of
groups of other centres, whose activity might interfere with that
of the group excited to action. In a simple reflex flexure of the
knee the motor-neurones to the flexor muscles are excited, but
concurrently the motor-neurones to the extensor muscles are thrown
into a state of inhibition, and so equally with all the varied
excitations of the nervous system controlling the movements and
activities of the entire body.
[Illustration: FIG. 34.
Diagrammatic representation of the structures present in a
typical cell (_after_ Wilson). Note the two centrosomes,
sometimes single.]
The discovery of the continuity of the protoplasm through the walls
of the vegetable cells by means of connecting canals and threads
(see fig. 33) is one of the most startling facts discovered in
connection with plant-structure, since it was held twenty years
ago that a fundamental distinction between animal and vegetable
structure consisted in the boxing-up or encasement of each vegetable
cell-unit in a case of cellulose, whereas animal cells were not so
imprisoned, but freely communicated with one another. It perhaps
is on this account the less surprising that lately something like
sense-organs have been discovered on the roots, stems, and leaves
of plants, which, like the otocysts of some animals, appear to be
really ‘statocytes,’ and to exert a varying pressure according to the
relations of these parts of the plant to gravity. There is apparently
something resembling a perception of the incidence of gravity in
plants which reacts on irritable tissues, and is the explanation of
the phenomena of geotropism. These results have grown out of the
observations of Charles Darwin, followed by those of F. Darwin,
Haberlandt, and Nemec.
[Illustration:
FIG. 35.--THE NUMBER OF THE CHROMOSOMES: (_a_) Cell of the asexual
generation of the cryptogam _Pellia epiphylla_: the nucleus is
about to divide, a polar ray-formation is present at each end of
the spindle-shaped nucleus, the chromosomes have divided into two
horizontal groups each of sixteen pieces: _sixteen_ is the number
of the chromosomes of the ordinary tissue cells of _Pellia_.
(_b_) Cell of the sexual generation of the same plant (_Pellia_)
in the same phase of division, but with the _reduced_ number
of chromosomes--namely, _eight_ in each half of the dividing
nucleus. The completed cells of the sexual generation have only
_eight_ chromosomes. (_c_) Somatic or tissue cell of Salamander
showing _twenty-four_ =V=-shaped chromosomes, each of which is
becoming longitudinally split as a preliminary to division.
(_d_) Sperm-mother-cell from testis of Salamander, showing the
_reduced_ number of chromosomes of the sexual cells--namely,
_twelve_; each is split longitudinally. (From original drawings
by Prof. Farmer and Mr. Moore.)]
A few words must be said here as to the progress of our knowledge of
cell-substance, and what used to be called the protoplasm question.
We do not now regard protoplasm as a chemical expression, but, in
accordance with von Mohl’s original use of the word, as a structure
which holds in its meshes many and very varied chemical bodies of
great complexity. Within these twenty-five years the ‘centrosome’
of the cell-protoplasm has been discovered (see fig. 34), and a
great deal has been learnt as to the structure of the nucleus and
its remarkable stain-taking bands, the chromosomes. We now know
that these bands are of definite fixed number, varying in different
species of plants and animals, and that they are halved in number in
the reproductive elements--the spermatozoid and the ovum--so that
on union of these two to form the fertilized ovum (the parent cell
of all the tissues), the proper specific number is attained (see
figs. 35 and 36). It has been pretty clearly made out by cutting
up large living cells--unicellular animals--that the body of the
cell alone, without the nucleus, can do very little but move and
maintain for a time its chemical status. But it is the nucleus which
directs and determines all definite growth, movement, secretion,
and reproduction. The simple protoplasm, deprived of its nucleus,
cannot form a new nucleus--in fact, can do very little but exhibit
irritability. I am inclined to agree with those who hold that there
is not sufficient evidence that any organism exists at the present
time which has not both protoplasm and nucleus--in fact, that the
simplest form of life at present existing is a highly complicated
structure--a nucleated cell. That does not imply that simpler forms
of living matter have not preceded those which we know. We must
assume that something more simple and homogeneous than the cell,
with its differentiated cell-body or protoplasm, and its cell kernel
or nucleus, has at one time existed. But the various supposed
instances of the survival to the present day of such simple living
things--described by Haeckel and others--have one by one yielded
to improved methods of microscopic examination and proved to be
differentiated into nuclear and extra-nuclear substance.
[Illustration: FIG. 36.
Further stage in the division of the sexual cell drawn in Fig.
35(_e_), showing the _twelve_ chromosomes of the two nuclei of
the sperm-cells resulting from the division (_twelve_ instead of
_twenty-four_).]
The question of ‘spontaneous generation’ cannot be said to have
been seriously revived within these twenty-five years. Our greater
knowledge of minute forms of life, and the conditions under which
they can survive, as well as our improved microscopes and methods
of experiment and observation, have made an end of the arguments
and instances of supposed abiogenesis. The accounts which have
been published of ‘radiobes,’ minute bodies arising in fluids of
organic origin when radium salts have been allowed to mix in minute
quantities with such fluids, are wanting in precision and detail, but
the microscopic particles which appear in the circumstances described
seem to be of a nature identical with the minute bodies well known
to microscopists and recognised as crystals modified by a colloid
medium. They have been described by Rainey, Harting, and Ord, on
different occasions, many years ago. They are not devoid of interest,
but cannot be considered as having any new bearing on the origin of
living matter.
_Psychology._--I have given a special heading to this subject because
its emergence as a definite line of experimental research seems to
me one of the most important features in the progress of science in
the past quarter of a century. Thirty-five years ago we were all
delighted by Fechner’s psycho-physical law, and at Leipzig I, with
others of my day, studied it experimentally in the physiological
laboratory of that great teacher, Carl Ludwig. The physiological
methods of measurement (which are the physical ones) have been more
and more widely, and with guiding intelligence and ingenuity, applied
since those days to the study of the activities of the complex organs
of the nervous system which are concerned with ‘mind’ or psychic
phenomena. Whilst some enthusiasts have been eagerly collecting
ghost stories and records of human illusion and fancy, the serious
experimental investigation of the human mind, and its forerunner
the animal mind, has been quietly but steadily proceeding in truly
scientific channels. The science is still in an early phase--that of
the collection of accurate observations and measurements--awaiting
the development of great guiding hypotheses and theories. But much
has been done, and it is a matter of gratification to Oxford men
that through the liberality of the distinguished electrician, Mr.
Henry Wilde, F.R.S., a lectureship of Experimental Psychology has
been founded in the University of Oxford, where the older studies
of Mental and Moral Philosophy, Logic and Metaphysics have so
strong a hold, and have so well prepared the ground for the new
experimental development. The German investigators W. Wundt, G. E.
Müller, C. Stumpf, Ebbinghaus, and Munsterberg have been prominent in
introducing laboratory methods, and have determined such matters as
the elementary laws of association and memory, and the perceptions of
musical tones and their relations. The work of Goldschneider on ‘the
muscular sense,’ of von Frey on the cutaneous sensations, are further
examples of what is being done.
The difficult and extremely important line of investigation, first
scientifically treated by Braid under the name ‘Hypnotism,’ has been
greatly developed by the French school, especially by Charcot. The
experimental investigation of ‘suggestion,’ and the pathology of dual
consciousness and such exceptional conditions of the mind, has been
greatly advanced by French observers.
The older work of Ferrier and Hitzig on the functions of the parts of
the brain has been carried further by Goltz and Munk in Germany, and
by Schäfer, Horsley, and Sherrington in England.
The most important general advance seems to be the recognition that
the mind of the human adult is a social product; that it can only
be understood in relation with the special environment in which it
develops, and with which it is in perpetual interaction. Professor
Baldwin, of Princeton, has done important work on this subject.
Closely allied is the study of what is called ‘the psychology of
groups,’ the laws of mental action of the individual as modified by
his membership of some form of society. French authors have done
valuable work here.
These two developments of psychology are destined to provide the
indispensable psychological basis for Social Science, and for the
anthropological investigation of mental phenomena.
Hereafter, the well-ascertained laws of experimental psychology will
undoubtedly furnish the necessary scientific basis of the art of
education, and psychology will hold the same relation to that art as
physiology does to the art of medicine and hygiene.
There can be little doubt, moreover, of the valuable interaction
of the study of physical psychology and the theories of the origin
of structural character by natural selection. The relation of the
human mind to the mind of animals, and the gradual development of
both, form a subject full of rich stores of new material, yielding
conclusions of the highest importance, which has not yet been
satisfactorily approached.
I am glad to be able to give wider publicity here to some conclusions
which I communicated to the Jubilee volume of the ‘Société de
Biologie’ of Paris in 1899. I there discussed the significance
of the great increase in the size of the cerebral hemispheres in
recent, as compared with Eocene Mammals (see fig. 5), and in Man as
compared with Apes, and came to the conclusion that ‘the power of
building up appropriate cerebral mechanism in response to individual
experience,’ or what may be called ‘educability,’ is the quality
which characterizes the larger cerebrum, and is that which has led to
its selection, survival, and further increase in volume. The bearing
of this conception upon questions of fundamental importance in what
has been called genetic psychology is sketched as follows:
‘The character which we describe as “educability” can be
transmitted; it is a congenital character. But the _results_ of
education can _not_ be transmitted. In each generation they have
to be acquired afresh. With increased “educability” they are more
readily acquired and a larger variety of them. On the other hand,
the nerve-mechanisms of instinct are transmitted, and owe their
inferiority as compared with the results of education to the very
fact that they are _not_ acquired by the individual in relation to
his particular needs, but have arisen by selection of congenital
variation in a long series of preceding generations.’
‘To a large extent the two series of brain-mechanisms, the
“instinctive” and the “individually acquired,” are in opposition to
one another. Congenital brain-mechanisms may prevent the education of
the brain and the development of new mechanisms specially fitted to
the special conditions of life. To the educable animal the less there
is of specialised mechanism transmitted by heredity, the better. The
loss of instinct is what permits and necessitates the education of
the receptive brain.’
‘We are thus led to the view that it is hardly possible for a theory
to be further from the truth than that expressed by George H. Lewes
and adopted by George Romanes, namely, that instincts are due to
“lapsed” intelligence. The fact is that there is no community between
the mechanisms of instinct and the mechanisms of intelligence, and
that the latter are later in the history of the development of the
brain than the former, and can only develop in proportion as the
former become feeble and defective.’[17]
_Darwinism._--Under the title ‘Darwinism’ it is convenient to
designate the various work of biologists tending to establish,
develop, or modify Mr. Darwin’s great theory of the origin of
species. In looking back over twenty-five years it seems to me
that we must say that the conclusions of Darwin as to the origin
of species by the survival of selected races in the struggle for
existence are more firmly established than ever. And this because
there have been many attempts to gravely tamper with essential parts
of the fabric as he left it, and even to substitute conceptions
for those which he endeavoured to establish, at variance with his
conclusions. These attempts must, I think, be considered as having
failed. A great deal of valuable work has been done in consequence;
for honest criticism, based on observation and experiment, leads to
further investigation, and is the legitimate and natural mode of
increase of scientific knowledge. Amongst the attempts to seriously
modify Darwin’s doctrine may be cited that to assign a great and
leading importance to Lamarck’s theory as to the transmission by
inheritance of newly ‘acquired’ characters, due chiefly to American
palæontologists and to the venerated defender of such views, who
has now closed his long life of great work, Mr. Herbert Spencer;
that to attribute leading importance to the action of physiological
congruity and incongruity in selective breeding, which was put
forward by another able writer and naturalist who has now passed
from among us, Dr. George Romanes; further, the views of de Vries
as to the discontinuity in the origin of new species, supported by
the valuable work of Mr. Bateson on discontinuous variation; and
lastly, the attempt to assign a great and general importance to
the facts ascertained many years ago by the Abbé Mendel as to the
cross-breeding of varieties and the frequent production (in regard
to certain characters in certain cases) of pure strains rather than
of breeds combining the characters of both parents. On the other
hand we have the splendid series of observations and writings of
August Weismann, who has, in the opinion of the majority of those
who study this subject, rendered the Lamarckian theory of the origin
and transmission of new characters altogether untenable, and has,
besides, furnished a most instructive, if not finally conclusive,
theory or mechanical scheme of the phenomena of Heredity in his book
‘The Germ-plasm.’ Professor Karl Pearson and the late Professor
Weldon--the latter so early in life and so recently lost to us--have,
with the finest courage and enthusiasm in the face of an enormous
and difficult task, determined to bring the facts of variation and
heredity into the solid form of statistical statement, and have
organised, and largely advanced in, this branch of investigation
which they have termed ‘Biometrics.’ Many naturalists throughout the
world have made it the main object of their collecting and breeding
of insects, birds, and plants, to test Darwin’s generalisations and
to expand the work of Wallace in the same direction. A delightful
fact in this survey is that we find Mr. Alfred Russel Wallace
(who fifty years ago conceived the same theory as that more fully
stated by Darwin) actively working and publishing some of the most
convincing and valuable works on Darwinism. He is still alive and
not merely well, but pursuing his work with vigour and ability.
It was chiefly through his researches on insects in South America
and the Malay Islands that Mr. Wallace was led to the Darwinian
theory; and there is no doubt that the study of insects, especially
of butterflies, is still one of the most prolific fields in which
new facts can be gathered in support of Darwin and new views on
the subject tested. Prominent amongst naturalists in this line of
research has been and is Edward Poulton of Oxford, who has handed on
to the study of entomology throughout the world the impetus of the
Darwinian theory. I must here also name a writer who, though unknown
in our laboratories and museums, seems to me to have rendered very
valuable service in later years to the testing of Darwin’s doctrines
and to the bringing of a great class of organic phenomena within the
cognisance of those naturalists who are especially occupied with
the problems of Variation and Heredity. I mean Dr. Archdall Reid,
who has with keen logic made use of the immense accumulation of
material which is in the hands of medical men, and has pointed out
the urgent importance of increased use by Darwinian investigators of
the facts as to the variation and heredity of that unique animal,
man, unique in his abundance, his reproductive activity, and his
power of assisting his investigator by his own record. There are
more observations about the variation and heredity of man and the
conditions attendant upon individual instances than with regard
to any other animal. Medical men need only to grasp clearly the
questions at present under discussion in order to be able to furnish
with ease data absolutely invaluable in quantity and quality. Dr.
Archdall Reid has in two original books full of insight and new
suggestions, the ‘Present Evolution of Man’ and ‘Principles of
Heredity,’ shown a new path for investigators to follow.
The attempt to resuscitate Lamarck’s views on the inheritance of
acquired[18] characters has been met not only by the demand for
the production of experimental proof that such inheritance takes
place, which has never been produced, but on Weismann’s part by a
demonstration that the reproductive cells of organisms are developed
and set aside from the rest of the tissues at so early a period
that it is extremely improbable that changes brought about in those
other tissues by unaccustomed incident forces can be communicated to
the germ-cells so as to make their appearance in the offspring by
heredity. Apart from this, I have drawn attention to the fact that
Lamarck’s first and second laws (as he terms them) of heredity are
contradictory the one of the other, and therefore may be dismissed.
In 1894 I wrote:
‘Normal conditions of environment have for many thousands of
generations moulded the individuals of a given species of organism,
and determined as each individual developed and grew “responsive”
quantities in its parts (characters): yet, as Lamarck tells us, and
as we know, there is in every individual born a potentiality which
has _not_ been extinguished. Change the normal conditions of the
species in the case of a young individual taken to-day from the site
where for thousands of generations its ancestors have responded
in a perfectly defined way to the normal and defined conditions
of environment; reduce the daily or the seasonal amount of solar
radiation to which the individual is exposed; or remove the aqueous
vapour from the atmosphere; or alter the chemical composition of
the pabulum accessible; or force the individual to previously
unaccustomed muscular effort or to new pressures and strains; and (as
Lamarck bids us observe), in spite of all the long-continued response
to the earlier normal specific conditions, the innate congenital
potentiality shows itself. The individual under the new quantities of
environing agencies shows _new_ responsive quantities in those parts
of its structure concerned, new or _acquired_ characters.
‘So far, so good. What Lamarck next asks us to accept, as his “second
law,” seems not only to lack the support of experimental proof, but
to be inconsistent with what has just preceded it. The new character
which is _ex hypothesi_, as was the old character (length, breadth,
weight of a part) which it has replaced--a response to environment,
a particular moulding or manipulation by incident forces of the
potential congenital quality of the race--is, according to Lamarck,
all of a sudden raised to extraordinary powers. The new or freshly
acquired character is declared by Lamarck and his adherents to be
capable of transmission by generation; that is to say, it alters
the potential character of the species. It is no longer a merely
responsive or reactive character, determined quantitatively by
quantitative conditions of the environment, but becomes fixed and
incorporated in the potential of the race, so as to persist when
other quantitative external conditions are substituted for those
which originally determined it. In opposition to Lamarck, one must
urge, in the first place, that this thing has never been shown
experimentally to occur; and in the second place, that there is
no ground for holding its occurrence to be probable, but, on the
contrary, strong reason for holding it to be improbable. Since
the old character (length, breadth, weight) had not become fixed
and congenital after many thousands of successive generations
of individuals had developed it in response to environment, but
gave place to a new character when new conditions operated on an
individual (Lamarck’s first law), why should we suppose that the new
character is likely to become fixed after a much shorter time of
responsive existence, or to escape the operation of the first law?
Clearly there is no reason (so far as Lamarck’s statement goes) for
any such supposition, and the two so-called laws of Lamarck are at
variance with one another.’
In its most condensed form my argument has been stated thus by
Professor Poulton: Lamarck’s ‘first law assumes that a past history
of indefinite duration is powerless to create a bias by which the
present can be controlled; while the second assumes that the brief
history of the present can readily raise a bias to control the
future.’[19]
An important light is thrown on some facts which seem at first sight
to favour the Lamarckian hypothesis by the consideration that,
though an ‘acquired’ character is not transmitted to offspring as
the consequence of the action of external agencies determining the
‘acquirement,’ yet the tendency to react exhibited by the parent
_is_ transmitted, and if the tendency is exceptionally great a
false suggestion of a Lamarckian inheritance can readily result.
This inheritance of ‘variation in tendencies to react’ has a wide
application, and has led me to coin the word ‘educability’ as
mentioned in the section of this address on Psychology.
The principle of physiological selection advocated by Dr. Romanes
does not seem to have caused much discussion, and has been unduly
neglected by subsequent writers. It was ingenious, and was based on
some interesting observations, but has failed to gain support.
The observations of de Vries--showing that in cultivated varieties of
plants a new form will sometimes assert itself suddenly and attain
a certain period of dominance, though not having been gradually
brought into existence by a slow process of selection--have
been considered by him, and by a good many other naturalists,
as indicating the way in which new species arise in Nature. The
suggestion is a valuable one if not very novel, but a great deal of
observation will have to be made before it can be admitted as really
having a wide bearing upon the origin of species. The same is true of
those interesting observations which were first made by Mendel, and
have been resuscitated and extended with great labour and ingenuity
by recent workers, especially in this country by Bateson and his
pupils. If it should prove to be true that varieties when crossed do
not, in the course of eventual inter-breeding, produce intermediate
forms as hybrids, but that characters are either dominant or
recessive, and that breeds result having pure unmixed characters--we
should, in proportion as the Mendelian law is shown to apply to all
tissues and organs and to a majority of organisms, have before us
a very important and determining principle in all that relates to
heredity and variation. It remains, however, to be shown how far
the Mendelian phenomenon is general. And it is, of course, admitted
on all sides that, even were the Mendelian phenomenon general and
raised to the rank of a law of heredity, it would not be subversive
of Mr. Darwin’s generalisations, but probably tend to the more ready
application of them to the explanation of many difficult cases of the
structure and distribution of organisms.
Two general principles which Mr. Darwin fully recognised appear to
me to deserve more consideration and more general application to the
history of species than he had time to give to them, or than his
followers have accorded to them. The first is the great principle
of ‘correlation of variation,’ from which it follows that, whilst
natural selection may be favouring some small and obscure change in
an unseen group of cells--such as digestive, pigmentary or nervous
cells, and that change a change of selective value--there may be,
indeed often is, as we know, a correlated or accompanying change in a
physiologically related part of far greater magnitude and prominence
to the eye of the human onlooker. This accompanying or correlated
character has no selective value, is not an adaptation--is, in
fact, a necessary but useless by-product. A list of a few cases of
this kind was given by Darwin, but it is most desirable that more
should be established. For they enable us to understand how it is
that specific characters, those seen and noted on the surface by
systematists, are not in most cases adaptations of selective value.
They also open a wide vista of incipient and useless developments
which may suddenly, in their turn, be seized upon by ever-watchful
natural selection and raised to a high pitch of growth and function.
The second, somewhat but by no means altogether neglected, principle
is that a good deal of the important variation in both plants and
animals is not the variation of a minute part or confined to one
organ, but has really an inner physiological basis, and may be a
variation of a whole organic system or of a whole tissue expressing
itself at several points and in several shapes. In fact, we should
perhaps more generally conceive of variation as not so much the
accomplishment and presentation of one little mark or difference in
weight, length, or colour, as the expression of a _tendency to vary_
in a given tissue or organ in a particular way. Thus we are prepared
for the rapid extension and dominance of the variation if once it is
favoured by selective breeding. It seems to me that such cases as
the complete disappearance of scales from the integument of some
osseous fishes, or the possible retention of three or four scales
out of some hundreds present in nearly allied forms, favour this
mode of conceiving of variation. So also does the marked tendency
to produce membranous expansions of the integument in the bats, not
only between the digits and from the axilla, but from the ears and
different regions of the face. Of course, the alternative hairy or
smooth condition of the integuments both in plants and animals is a
familiar instance in which a tendency extending over a large area
is recognised as that which constitutes the variation. In smooth or
hairy varieties we do not postulate an individual development of
hairs subjected one by one to selection and survival or repression.
_Disease._--The study of the physiology of unhealthy, injured, or
diseased organisms is called pathology. It necessarily has an immense
area of observation and is of transcending interest to mankind who
do not accept their diseases unresistingly and die as animals do,
so purifying their race, but incessantly combat and fight disease,
producing new and terrible forms of it, by their wilful interference
with the earlier rule of Nature.
Our knowledge of disease has been enormously advanced in the last
quarter of a century, and in an important degree our power of
arresting it, by two great lines of study going on side by side
and originated, not by medical men nor physiologists in the narrow
technical sense, but by naturalists, a botanist, and a zoologist.
Ferdinand Cohn, Professor of Botany in Breslau, by his own researches
and by personal training in his laboratory, gave to Robert Koch the
start on his distinguished career as a bacteriologist. It is to
Metschnikoff the zoologist and embryologist that we owe the doctrine
of phagocytosis and the consequent theory of immunity now so widely
accepted.
We must not forget that in this same period much of the immortal
work of Pasteur on hydrophobia, of Behring and Roux on diphtheria,
and of Ehrlich and many others to whom the eternal gratitude of
mankind is due, has been going on. It is only some fifteen years
since Calmette showed that if cobra poison were introduced into the
blood of a horse in less quantity than would cause death, the horse
would tolerate with little disturbance after ten days a full dose,
and then day after day an increasing dose, until the horse without
any inconvenience received an injection of cobra poison large enough
to kill thirty horses of its size. Some of the horse’s blood being
now withdrawn was found to contain a very active antidote to cobra
poison--what is called an antitoxin. The procedure in the preparation
of the antitoxin is practically the same as that previously adopted
by Behring in the preparation of the antitoxin of diphtheria poison.
Animals treated with injections of these antitoxins are immune to
the poison itself when subsequently injected with it, or, if already
suffering from the poison (as, for instance, by snake-bite), are
readily shown by experiment to be rapidly cured by the injection of
the appropriate antitoxin. This is, as all will admit, an intensely
interesting bit of biology. The explanation of the formation of the
antitoxin in the blood and its mode of antagonising the poison is
not easy. It seems that the antitoxin is undoubtedly formed from the
corresponding toxin or poison, and that the antagonism can be best
understood as a chemical reaction by which the complex molecule of
the poison is upset, or effectively modified.
The remarkable development of Metschnikoff’s doctrine of phagocytosis
during the past quarter of a century is certainly one of the
characteristic features of the activity of biological science in that
period. At first ridiculed as ‘Metschnikoffism,’ it has now won the
support of its former adversaries.
For a long time the ideal of hygienists has been to preserve man from
all contact with the germs of infection, to destroy them and destroy
the animals conveying them, such as rats, mosquitoes, and other
flies. But it has now been borne in upon us that, useful as such
attempts are, and great as is the improvement in human conditions
which can thus be effected, yet we cannot hope for any really
complete or satisfactory realisation of the ideal of escape from
contact with infective germs. The task is beyond human powers. The
conviction has now been arrived at that, whilst we must take every
precaution to diminish infection, yet our ultimate safety must come
from within--namely, from the activity, the trained, stimulated, and
carefully guarded activity, of those wonderful colourless amœba-like
corpuscles whose use was so long unrecognized, but has now been
made clear by the patiently continued experiments and arguments of
Metschnikoff, who has named them ‘phagocytes.’ The doctrine of the
activity and immense importance of these corpuscles of the living
body which form part of the all-pervading connective tissues and
float also in the blood, is in its nature and inception opposed to
what are called the ‘humoral’ and ‘vitalistic’ theories of resistance
to infection. Of this kind were the beliefs that the _liquids_ of the
living body have an inherent and somewhat vague power of resisting
infective germs, and even that the mere living quality of the
tissues was in some unknown way antagonistic to foreign intrusive
disease-germs.
[Illustration:
FIG. 37. FIG. 38. FIG. 39.
Fig. 37.--Phagocyte or colourless corpuscle of a guinea-pig
in the act of engulphing two Spirilla or parasitic vegetable
microbes of a spiral shape. Fig. 38.--The same half an hour
later, one of the Spirilla is nearly completely engulphed. Fig.
39.--The same ten minutes later still, one of the Spirilla is
completely absorbed into the substance (protoplasm) of the
phagocyte. (_From_ Metschnikoff’s book, “Immunity,” kindly
supplied by the Cambridge University Press.)]
The first eighteen years of Metschnikoff’s career, after his
undergraduate course, were devoted to zoological and embryological
investigations. He discovered many important facts, such as the
alternation of generations in the parasitic worm of the frog’s
lung--_Ascaris nigrovenosa_--and the history of the growth from the
egg of sponges and medusæ. In these latter researches he came into
contact with the wonderfully active cells, or living corpuscles,
which in many low forms of life can be seen by transparency in the
living animal. He saw that these corpuscles (as was indeed already
known) resemble the well-known amœba, and can take into their soft
substance (protoplasm) at all parts of their surface any minute
particles and digest them, thus destroying them. In a transparent
water-flea Metschnikoff saw these amœba-like, colourless, floating
blood-corpuscles swallowing and digesting the spores of a parasitic
fungus which had attacked the water-fleas and was causing their
death. He came to the conclusion that this is the chief, if not
the whole, value of these corpuscles in higher as well as lower
animals, in all of which they are very abundant. It was known that
when a wound bringing in foreign matter is inflicted on a vertebrate
animal the blood-vessels became gorged in the neighbourhood and
the colourless corpuscles escape through the walls of the vessels
in crowds. Their business in so doing, Metschnikoff showed, is to
eat up the foreign matter, and also to eat up and remove the dead,
wounded tissue. He therefore called these white or colourless
corpuscles ‘phagocytes,’ the eater-cells, and in his beautiful book
on Inflammation, published twenty years ago, proved the extreme
importance of their activity. At the same time he had shown that
they eat up intrusive bacteria and other germs (see figs. 37 to
43); and his work for the last twenty years has mainly consisted
in demonstrating that they are the chief, and probably the only,
agents at work in either ridding the human body of an attack of
disease-causing germs or in warding off even the commencement of an
attack, so that the man or animal in which they are fully efficient
is ‘immune’--that is to say, cannot be effectively attacked by
disease-germs.
[Illustration:
FIG. 40. FIG. 41. FIG. 42.
Fig. 40.--Phagocyte of a guinea-pig in the course of engulphing
a very mobile undulating spirillum. Fig. 41.--The same, forty
minutes later. Fig. 42.--The same taken half an hour after Fig.
41. (_From_ Metschnikoff’s “Immunity.”)]
[Illustration: FIG. 43.
A large kind of phagocyte of the guinea-pig, killed and stained
for microscopic examination. It shows the large spherical nucleus
and three specimens of the spirillum of relapsing-fever which
have been engulphed, and are lying within its protoplasm. They
would have been slowly digested--that is to say, dissolved by the
digestive juices within the phagocyte. (_From_ Metschnikoff’s
“Immunity.”)]
Disease-germs, bacteria, or protozoa produce poisons which sometimes
are too much for the phagocytes, poisoning them and so getting
the upper hand. But, as Metschnikoff showed, the training of the
phagocytes by weak doses of the poison of the disease-germ, or by
weakened cultures of the disease-germ itself, brings about a power
of resistance in the phagocytes to the germ’s poison, and thus makes
them capable of attacking the germs and keeping them at bay. Hence
the value of inoculations.
The discussion and experiments arising from Metschnikoff’s
demonstrations have led to the discovery of the production by the
phagocytes of certain exudations from their substance which have a
most important effect in weakening the resistance of the intrusive
bacteria and rendering them easy prey for the phagocyte. These
are called ‘sensitisers,’ and have been largely studied. They may
be introduced artificially into the blood and tissues so as to
facilitate the work of the phagocytes, and no doubt it is a valuable
remedial measure to make use of such sensitisers as a treatment.
Dr. Wright considers that such sensitisers are formed in the blood
and tissues independently of the phagocytes, and has called them
‘opsonins,’ under which name he has made most valuable application
of the method of injecting them into the body so as to facilitate
the work of the phagocytes in devouring the hostile bacteria of
various diseases. Each kind of disease-producing microbe has its own
sensitiser or opsonin; hence there has been much careful research and
experiment required in order to bring the discovery into practical
use. Metschnikoff himself holds and quotes experiments to show that
the ‘opsonins’ are actually produced by the phagocytes themselves.
That this should be so is in accordance with some striking zoological
facts, as I pointed out nearly twenty years ago.[20] For the lowest
multicellular animals provided with a digestive sac or gut, such
as the polyps, have that sac lined by digestive cells which have
the same amœboid character as ‘phagocytes,’ and actually digest
to a large extent by swallowing or taking into their individual
protoplasm raw particles of food. Such particles are enclosed in a
temporary cavity, or vacuole, into which the cell-protoplasm secretes
digestive ferment and other chemical agents. Now there is no doubt
that such digestive vacuoles may burst and so pour out into the
polyp’s stomach a digestive juice which will act on food particles
outside the substance of the cells, and thus by the substitution of
this process of outpouring of the secretion for that of ingestion of
food particles into the cells we get the usual form of digestion by
juices secreted into a digestive cavity. Now this being certainly the
case in regard to the history of the original phagocytes lining the
polyp’s gut, it does not seem at all unlikely, but on the contrary in
a high degree probable, that the phagocytes of the blood and tissues
should behave in the same way and pour out sensitisers and opsonins
to paralyse, and prepare their bacterial food. And the experiments
of Metschnikoff’s pupils and followers show that this is undoubtedly
the case. Whether there is any great variety of and difference
between ‘sensitisers’ and ‘opsonins’ is a matter which is still the
subject of active experiment. Metschnikoff’s conclusion, as recently
stated in regard to the whole progress of this subject, is that the
phagocytes in our bodies should be stimulated in their activity in
order successfully to fight the germs of infection. Alcohol, opium,
and even quinine, hinder the phagocytic action; they should therefore
be entirely eschewed or used only with great caution where their
other and valuable properties are urgently needed. It appears that
the injection of blood-serum into the tissues of animals causes an
increase in the number and activity of the phagocytes, and thus an
increase in their resistance towards pathogenic germs. Thus Durham
(who was a pioneer in his observations on the curious phenomena of
the ‘agglutination’ of blood corpuscles in relation to disease) was
led to suggest the injection of sera during surgical operations, and
experiments recently quoted by Metschnikoff seem to show that the
suggestion was well founded. Both German and French surgeons have
employed the method with successful results, and the demonstration
that an immense number of microbes are thus taken up and destroyed by
the multiplication (due to their regular increase by cell-division)
of the phagocytes of the injected patient. After years of opposition
bravely met in the pure scientific spirit of renewed experiment
and demonstration, Metschnikoff is at last able to say that the
foundation-stone of the hygiene of the tissues--the thesis that our
phagocytes are our arms of defence against infective germs--has been
generally accepted.
Another feature of the progress of our knowledge of disease--as a
scientific problem--is the recent recognition that minute animal
parasites of that low degree of unicellular structure to which the
name ‘Protozoa’ is given, are the causes of serious and ravaging
diseases, and that the minute algoid plants, the bacteria, are not
alone in possession of this field of activity. It was Laveran--a
French medical man--who, just about twenty-five years ago, discovered
the minute animal organism in the red blood-corpuscles, which is the
cause of malaria (see fig. 44). Year by year ever since our knowledge
of this terrible little parasite has increased. We now know many
similar to, but not identical with it, living in the blood of birds,
reptiles, and frogs (see fig. 45).
It is the great merit of Major Ross, formerly of the Indian Army
Medical Staff, to have discovered, by most patient and persevering
experiment, that the malaria parasite passes a part of its life in
the spot-winged gnat or mosquito (_Anopheles_), not, as he had at
first supposed, in the common gnat or mosquito (_Culex_), and that if
we can get rid of spot-winged mosquitoes or avoid their attentions,
or even only prevent them from sucking the blood of malarial
patients, we can lessen, or even abolish, malaria.
[Illustration: FIG. 44.
SCHIZOGONY
SPOROGONY
SEXUAL GENERATION
A diagram showing the life-history and migration of the Malaria
parasite, _Laverania Malariæ_, as discovered by Laveran, Ross,
and Grassi. The stages above the dotted line take place in the
blood of man. The oblong-pointed parasite is seen entering the
blood at _n_ just below No. 1. The circles represent the red
blood-discs of man. Schizogony means multiplication by simple
division or splitting, and it is seen in Nos. 6, 7, 8, 9, and
10. The stages below the dotted line are passed in the body
of the spot-winged gnats of the genus _Anopheles_. A peculiar
crescent or sausage-shaped condition is assumed by the parasite
inside the red corpuscle No. VI. These are found to be of two
kinds, male and female, Nos. VIIa and VIIb. They are swallowed
by the spot-winged gnat when it sucks the blood of an infected
man. Here in the gut of the gnat they become spherical; the male
spheres produce spermatozoa No. Xa, which fuse with and fertilize
the female spheres or egg-cells No. XI. An active worm-like
form No. XIII results, which pushes its way partly through the
wall of the gnat’s gut, and is then nourished by the gnat’s
blood. It swells up, divides internally again and again, and is
enclosed in a firm transparent case or cyst, Nos. XIV to XVIII.
The cysts are far larger in proportion than is shown in the
diagram, and are visible to the naked eye. The final product of
the breaking up, which is called sporogony, is a vast number of
needle-shaped spores or young (called Exotospores, as opposed to
the Enhæmospores, which are formed in the human blood, as seen in
Nos. 9 and 10, and serve there to spread the infection among the
red corpuscles). The needle-shaped spores formed in the gnat’s
body accumulate in its salivary glands, and pass out by the mouth
of the gnat when it stabs a new human victim who thus becomes
infected, No. XIX.
Had the sausage-like phases Nos. VIIa and VIIb been swallowed by
a common gnat or mosquito of the genus _Culex_ they would have
been digested and destroyed. It is only in species of gnats of
the kind known as _Anopheles_ that the parasite can undergo its
sexual development and subsequent process of the formation of
cysts and needle-shaped exotospores. (After Minchin in Part I. of
Lankester’s “Treatise on Zoology,” published by A. and C. Black.)]
This great discovery was followed by another as to the production
of the deadly ‘Nagana’ horse and cattle disease in South Africa by
a screw-like, minute animal parasite _Trypanosoma Brucei_ (see fig.
46 B). The Tsetze fly (see fig. 48 A, B), which was already known in
some way to produce this disease, was found by Colonel David Bruce
to do so by conveying by its bite the Trypanosoma from wild big-game
animals, to the domesticated horses and cattle of the colonists.
The discovery of the parasite and its relation to the fly and
the disease was as beautiful a piece of scientific investigation
as biologists have ever seen. A curious and very important fact
was discovered by Bruce--namely, that the native big game (zebras,
antelopes, and probably buffaloes), are _tolerant_ of the parasite.
The _Trypanosoma_ grows and multiplies in their blood, but does
not kill them or even injure them. It is only the unaccustomed
introduced animals from Europe which are poisoned by the chemical
excreta of the Trypanosomes and die in consequence. Hence the wild
creatures--brought into a condition of tolerance by natural selection
and the dying out of those susceptible to the poison--form a sort of
‘reservoir’ of deadly Trypanosomes for the Tsetze flies to carry into
the blood of new-comers. The same phenomenon of ‘reservoir-hosts’ (as
I have elsewhere called them) has since been observed in the case of
malaria; the children of the native blacks in Africa and in other
malarious regions are _tolerant_ of the malarial parasite, as many
as 80 per cent. of children under ten being found to be infected,
and yet not suffering from the poison. This is not the same thing as
the immunity which consists in _repulsion_ or _destruction_ of the
parasite.
[Illustration: FIG. 45.
_Lankesterella ranarum_ (Lank.), the parasite of the red
blood-corpuscles of the edible Frog, described originally as
_Drepanidium ranarum_ by Lankester in 1882, and previously
without name in 1871. The large ovals represent the red
corpuscles of the frog; the dark central mass is the nucleus,
N. In A two spindle-shaped parasites are seen; in B one larger
parasite with nucleus _n_ preparing to divide; in C the parasite
is =V=-shaped. In D the parasite has become spherical, and is so
in E also. In F the spherical parasite has divided into a number
of spores _mz_, with a central residual body _np_. The figures G
to N represent supposed stages in conjugation of small and large
forms; O is an encysted phase; and P a spore or sporozoite of
the sexual generation similar to the needle-shaped exotospores
of Laverania. (See Fig. 44.) All the figures magnified 2,250
diameters. (After Hintze from Minchin’s section on Sporozoa in
Lankester’s “Treatise on Zoology.”)]
[Illustration: FIG. 46.
Various species of _Trypanosoma_ from the blood of mammals,
birds, and reptiles. A. _T. Lewisii_, from the blood of rats; B.
_T. Brucei_, the parasite of the Nagana or Tsetze-fly disease,
found in the blood of horses, cattle, and big game; C. _T.
gambiense_, the parasite causing Sleeping Sickness in man; D. _T.
equinum_, which causes the _mal de caderas_ in South American
horse ranches; E. _T. noctuæ_, from the blood of the little
owl, _Athene noctua_; F. _T. avium_, found in the blood of many
birds; G. a species found in the blood of Indian pigeons; H. _T.
ziemanni_, a second species from the blood of the little owl; J.
_T. damoniæ_, from the blood of a tortoise; _c.g._, granules;
_v._, vacuole; _l.s._, fold of the crest or undulating membrane.
These figures are from Dr. Woodcock’s article on the
“Hæmoflagellates” in the _Quarterly Journal of Microscopical
Science_, April and June, 1906. (See also the figures in the next
chapter relating to Sleeping Sickness.)]
The Trypanosomes have acquired a terrible notoriety within the last
four years, since another species, also carried by a Tsetze fly
of another species, has been discovered by Castellani in cases of
Sleeping Sickness in Uganda, and demonstrated by Colonel Bruce to be
the cause of that awful disease.[21] Over 200,000 natives of Uganda
have died from it within the last five years. It is incurable, and,
sad to relate, not only a certain number of European employés have
succumbed to it in tropical Africa, but a brave young officer of the
Army Medical Corps, Lieutenant Tulloch, has died from the disease
acquired by him in the course of an investigation of this disease and
its possible cure, which he was carrying out, in association with
other men of science, on the Victoria Nyanza Lake in Central Africa.
Lieutenant Tulloch was sent out to this investigation by the Royal
Society of London, and I will venture to ask my readers to join that
body in sympathy for his friends, and admiration for him and the
other courageous men who risk their lives in the endeavour to arrest
disease.
Trypanosomes are now being recognised in the most diverse regions
of the world as the cause of disease--new horse diseases in South
America, in North Africa, in the Philippines and East India are all
traced to peculiar species of Trypanosome. Other allied forms are
responsible for Delhi-sore, and certain peculiar Indian fevers of
man. A peculiar and ultra-minute parasite of the blood cells causes
Texas fever, and various African fevers deadly to cattle. In all
these cases, as also in that of plague, the knowledge of the carrier
of the disease, often a tick or acarid--in that of plague the flea
of the rat--is extremely important, as well as the knowledge of
reservoir-hosts when such exist.
The zoologist thus comes into closer touch than ever with the
profession of medicine, and the time has arrived when the
professional students of disease fully admit that they must bring
to their great and hopeful task of abolishing the diseases of man
the fullest aid from every branch of biological science. I need
not say how great is the contentment of those who have long worked
at apparently useless branches of science--such as are the careful
and elaborate distinction of every separate kind of animal and the
life-history and structure peculiar to each--in the belief that all
knowledge is good, to find that the science they have cultivated has
become suddenly and urgently of the highest practical value.
I have not time to do more than mention here the effort that is
being made by combined international research and co-operation
to push further in our knowledge of phthisis and of cancer, with
a view to their destruction. It is only since our last meeting
at York that the parasite of Phthisis or Tubercle has been made
known; we may hope that it will not be long before we have similar
knowledge as to Cancer. Only eighteen months have elapsed since Fritz
Schaudinn discovered the long-sought parasitic germ of Syphilis, the
_Spirochæta pallida_ (see fig. 6). As I write these words the sad
news of Schaudinn’s death at the age of thirty-five comes to me from
his family at Hamburg--an irreparable loss.
Let me finally state, in relation to this study of disease, what
is the simple fact--namely, that if the people of Britain wish to
make an end of infective and other diseases they must take every
possible means to discover capable investigators, and employ them
for this purpose. To do this, far more money is required than is at
present spent in that direction. It is necessary, if we are to do
our utmost, to spend a thousand pounds of public money on this task
where we now spend one pound. It would be reasonable and wise to
expend ten million pounds a year of our revenues on the investigation
and attempt to destroy disease. Actually what is so spent is a mere
nothing, a few thousands a year. Meanwhile our people are dying by
thousands of preventable disease.
2. THE ADVANCEMENT OF SCIENCE AS MEASURED BY THE SUPPORT GIVEN TO IT
BY PUBLIC FUNDS, AND THE RESPECT ACCORDED TO SCIENTIFIC WORK BY THE
BRITISH GOVERNMENT AND THE COMMUNITY AT LARGE.
Whilst I have been able, though in a very fragmentary and incomplete
way, to indicate the satisfactory and, indeed, the wonderful progress
of science in the last quarter of a century, so far as the making of
new knowledge is concerned, I am sorry to say that there is by no
means a corresponding ‘advancement’ of Science in that signification
of the word which implies the increase of the influence of science
in the life of the community, the increase of the support given to
it, and of the desire to aid in its progress, to discover and then
to encourage and reward those who are specially fitted to increase
scientific knowledge, and to bring it to bear so as to promote the
welfare of the community.
It is, unfortunately, true that the successive political
administrators of the affairs of this country, as well as the
permanent officials, are altogether unaware to-day, as they were
twenty-five years ago, of the vital importance of that knowledge
which we call science, and of the urgent need for making use of it
in a variety of public affairs. Whole departments of Government in
which scientific knowledge is the one thing needful are carried on by
ministers, permanent secretaries, assistant secretaries and clerks
who are wholly ignorant of science, and naturally enough dislike
it, since it cannot be used by them, and is in many instances the
condemnation of their official employment. Such officials are, of
course, not to be blamed, but rather the general indifference of the
public to the unreasonable way in which its interests are neglected.
A difficult feature in treating of this subject is that when one
mentions the fact that ministers of State and the officials of
the public service are not acquainted with science, and do not
even profess to understand its results or their importance, one’s
statement of this very obvious and notorious fact is apt to be
regarded as a personal offence. It is difficult to see wherein
the offence lies, for no one seeks to blame these officials for a
condition of things which is traditional and frankly admitted.
This is really a very serious matter for the scientific world to
consider and deal with. We represent a line of activity, a group
of professions which are in our opinion of vital importance to the
well-being of the nation. We know that those interests which we value
so highly are not merely ignored and neglected, but are actually
treated as of no account or as non-existent by the old-established
class of politicians and administrators. It is not too much to say
that there is a natural fear and dislike of scientific knowledge
on the part of a large proportion of the persons who are devoid of
it, and who would cease to hold, or never have held, the positions
of authority or emolument which they now occupy, were scientific
knowledge of the matters with which they undertake to deal required
of them. This is a thorny subject, and one in which, however much
one may endeavour to speak in general terms, it is difficult to
avoid causing personal annoyance. Yet it seems to me one of urgent
importance. Probably an inquiry into and discussion of the neglect
of science and the questionable treatment of scientific men by the
administrative departments of Government might with advantage be
undertaken by a committee appointed by our great scientific societies
for the purpose.
At the same time public attention should be drawn in general terms
to the fact that science is not gaining ‘advancement’ in public and
official consideration and support. The reason is, I think, to be
found in the defective education, both at school and university,
of our governing class, as well as in a racial dislike among all
classes to the establishment and support by public funds of posts
which the average man may not expect to succeed by popular clamour
or class privilege in gaining for himself--posts which must be held
by men of special training and mental gifts. Whatever the reason
for the neglect, the only remedy which we can possibly apply is
that of improved education for the upper classes, and the continued
effort to spread a knowledge of the results of science and a love
for it amongst all members of the community. If believers in science
took this matter seriously to heart they might do a great deal by
insisting that their sons, and their daughters too, should have
reasonable instruction in science both at school and college. They
could, by their own initiative and example, do a good deal to put an
end to the trifling with classical literature and the absorption in
athletics which is considered by too many schoolmasters as that which
the British parent desires as the education of his children.
Within the past year a letter has been published by a well-known
nobleman, who is one of the Trustees of the British Museum, holding
up to public condemnation the method in which the system laid down
by the officials of the Treasury and sanctioned by successive
Governments, as to the remuneration of scientific men, was applied
in an individual case. I desire to place on record here the Earl of
Crawford’s letter to the ‘Times’ of October 31, 1905, for the careful
consideration of those who desire the advancement of science. When
such things are done, science cannot be said to have advanced much in
public consideration or Governmental support.
_To the Editor of the ‘Times.’_
SIR,--The death, noted by you to-day, of my dear friend and
colleague Dr. Copeland, His Majesty’s Astronomer for Scotland,
creates a vacancy in the scientific staff of Great Britain.
Will you permit me, Sir, to offer a word of warning to any who
may be asked to succeed him?
Students or masters of astronomy are not, in the selfish sense,
business men, nor are they as a general rule overburdened with
this world’s goods. It behoves them henceforth to take more care
as to their future in case of illness or physical infirmity and
not to trust to the gratitude or generous impulse of the Treasury
Department.
In old days it was the custom when a man distinguished in science
was brought into a high position in the Civil Service that he
was credited with a certain number of years’ service ranking for
pension. This practice has been done away with, and a bargain
system substituted. A short while ago the growing agonies of
heart disease caused Dr. Copeland to feel that he was less able
to carry on the duties of his post, and he determined to resign;
but he learnt that under the scale, and in the absence of any
special bargain, the pension he would receive would not suffice
for the necessities of life. The only increase his friends
could get from the Treasury was an offer to allow him about
half-a-crown a week extra by way of a house.
Indignant and ashamed of my Government, I persuaded Dr. Copeland
to withdraw his resignation and to retain the official position
which he has honoured till his death.
I trust, Sir, that this memorandum of mine may cause eminent men
of science who are asked to enter the service of the State when
already of middle age to take heed for their future welfare.
I am, Sir, your obedient servant,
CRAWFORD.
2 Cavendish Square, October 28.
It is more agreeable to me not to dwell further on the comparative
failure of science to gain increased influence and support in this
country, but to mention some instances on the other side of the
account. As long ago as 1842 the British Association took over and
developed an observatory in the Deer Park at Kew, which was placed
at the disposal of the Association by Her Majesty the Queen. Until
1871 the Association spent annually a large part of its income--as
much in later years as 600_l._ a year--in carrying on the work of
the Kew Observatory, consisting of magnetic, meteorological and
physical observations. In 1871 the Association handed over the
Observatory to the Royal Society, which had received an endowment
of 10,000_l._ from Mr. Gassiot for its maintenance, and had further
devoted to that purpose considerable sums from its own Donation Fund
and Government Grant. Further aid for it was also received from
private sources. From this Observatory at last has sprung, in the
beginning of the present century, the National Physical Laboratory
in Bushey Park, a fine and efficient scientific institution, built
and supported by grants from the State, and managed by a committee
of really devoted men of science who are largely representatives of
the Royal Society. In addition to the value of the site and buildings
occupied by the National Physical Laboratory, the Government has
contributed altogether 34,000_l._ to the capital expenditure on
new buildings, fittings, and apparatus, and has further assigned a
grant of 6,000_l._ a year to the working of the laboratory. This
institution all men of science are truly glad to have gained from the
State, and they will remember with gratitude the statesmen--the late
Marquis of Salisbury, the Right Hon. Arthur J. Balfour, Mr. Haldane,
and others--as well as their own leaders--Lord Rayleigh, Sir William
Huggins, and the active body of physicists in the Royal Society who
have carried this enterprise to completion. The British Association
has every reason to be proud of its share in early days in nursing
the germ at Kew which has at length expanded into this splendid
national institution.
I may mention also another institution which, during the past quarter
of a century, has come into existence and received, originally
through the influence of the late Lord Playfair (one of the few
men of science who has ever occupied the position of a Minister of
the Crown), and later by the influence of the Right Hon. Joseph
Chamberlain, a subsidy of 1,000_l._ a year from the Government and
a contribution of 5,000_l._ towards its initial expenses. This is
the Marine Biological Association,[22] which has a laboratory at
Plymouth (see fig. 47), and has lately expended a special annual
grant, at the spontaneous invitation of His Majesty’s Treasury, in
conducting an investigation of the North Sea in accordance with an
international scheme devised by a central committee of scientific
experts. This scheme has for its purpose the gaining such knowledge
of the North Sea and its inhabitants as shall be useful in dealing
practically and by legislation with the great fisheries of that
area. The reader will, perhaps, not be surprised to hear that there
are persons in high positions who, though admittedly unacquainted
with the scientific questions at issue or the proper manner of
solving them, are discontented with the action of the Government in
entrusting the expenditure of public money to a body of scientific
men who give their services, without reward or thanks, to carrying
out the purposes of the international inquiry. Strange criticisms
are offered by these malcontents in regard to the work done in the
international exploration of the North Sea, and a desire is expressed
to secure the money for expenditure by a less scientific agency. I
do not hesitate to say here that the results obtained by the Marine
Biological Association are of great value and interest, and, if
properly continued and put to practical application, are likely to
benefit very greatly the fishery industry; on the other hand, if the
work is cut short or entrusted to incompetent hands it will no doubt
be the case that what has already been done will lose its value--that
is to say, will have been wasted. There is imminent danger of this
perversion of the funds assigned to this scientific investigation
taking place. There is no guarantee for the continuance of any funds
or offices assigned to science in one generation by the officials
of the next. The Mastership of the Mint held by Isaac Newton, and
finally by the great chemist Thomas Graham, has been abolished and
its salary appropriated by non-scientific officials. Only a few years
ago it was with great difficulty that the Government of the day was
prevented from assigning the Directorship of Kew Gardens to a young
man of influence devoid of all knowledge of botany!
[Illustration: FIG. 47.
The Laboratory of the Marine Biological Association on the
Citadel Hill, Plymouth, overlooking Plymouth Sound. The
laboratory was built with the aid of funds raised by public
subscription and a contribution of £5,000 by H.M. Government,
and cost £12,200. The Association has expended, exclusive of
this sum, since the opening of the laboratory in 1884, about
£62,000, or an average of £3,000 a year on the maintenance of
the laboratory, steam-boat and fishing-boats, and in payment of
a staff of scientific observers. Of this sum the Government has
contributed one-third, the rest has come from private donations
and subscriptions, and from the “earnings” of the laboratory
by sale of specimens, admission fees to the tank-room, &c. The
journal of the Association, published at intervals, records a
vast amount of scientific work, advancing our knowledge of marine
life and of the life-history of fishes.
_In addition to the above expenditure and results_, the
Association has superintended and most carefully directed the
expenditure of £6,000 a year during the past five years in the
investigation of the southern area of the North Sea and of the
Channel at the request of H.M. Government, the work being part
of the International Investigation of the North Sea. The very
voluminous results of these inquiries are published in special
reports by the International Committee. Full particulars of the
work of the Marine Biological Association can be obtained from
Dr. E. J. Allen, the Director, the Laboratory, Citadel Hill,
Plymouth, who will also receive donations and applications for
membership of the Association.]
One of the most solid tests of the esteem and value attached to
scientific progress by the community is the dedication of large sums
of money to scientific purposes by its wealthier members. We know
that in the United States such gifts are not infrequent; they are
rare in this country. It is, therefore, with especial pleasure that
I call attention to a great gift to science in this country made
only a few years ago. Lord Iveagh has endowed the Lister Institute,
for researches in connection with the prevention of disease, with
no less a sum than a quarter of a million pounds sterling. This is
the largest gift ever made to science in this country, and will be
productive of great benefit to humanity. The Lister Institute took
its origin in the surplus of a fund raised (at my suggestion and
with my assistance as secretary) by Sir James Whitehead when Lord
Mayor, some sixteen years ago, for the purpose of making a gift to
the Pasteur Institute in Paris, where many English patients had been
treated, without charge, after being bitten by rabid dogs. Three
thousand pounds was sent to M. Pasteur, and the surplus of a few
hundred pounds was made the starting-point of a fund which grew, by
one generous gift and another, until the Lister Institute on the
Thames Embankment at Chelsea was set up on a site presented by that
good and high-minded man, the late Duke of Westminster.
Many other noble gifts to scientific research have been made in this
country during the period on which we are looking back. Let us be
thankful for them, and admire the wise munificence of the donors. But
none the less we must refuse to rely entirely on such liberality for
the development of the army of science, which has to do battle for
mankind against the obvious disabilities and sufferings which afflict
us and can be removed by knowledge. The organisation and finance of
this army should be the care of the State.
It is a fact which many who have observed it regret very keenly, that
there is to-day a less widespread interest than formerly in natural
history and general science, outside the strictly professional arena
of the school and university. The field naturalists among the squires
and the country parsons seem nowadays not to be so numerous and
active in their delightful pursuits as formerly, and the Mechanics’
Institutes and Lecture Societies of the days of Lord Brougham have
given place, to a very large extent, to musical performances,
bioscopes, and other entertainments, more diverting, but not really
more capable of giving pleasure than those in which science was
popularised. No doubt the organisation and professional character of
scientific work are to a large extent the cause of this falling-off
in its attraction for amateurs. But perhaps that decadence is also
due in some measure to the increased general demand for a kind of
manufactured gaiety, readily sent out in these days of easy transport
from the great centres of fashionable amusement to the provinces and
rural districts.
Before concluding this retrospect, I would venture to allude to the
relations of scientific progress to religion. Putting aside the
troubles connected with special creeds and churches and the claims
of the clerical profession to certain funds and employments to the
exclusion of laymen, it should, I think, be recognized that there is
no essential antagonism between the scientific spirit and what is
called the religious sentiment. ‘Religion,’ said Bishop Creighton,
‘means the knowledge of our destiny and of the means of fulfilling
it.’ We can say no more and no less of Science. Men of Science seek,
in all reverence, to discover the Almighty, the Everlasting. They
claim sympathy and friendship with those who, like themselves, have
turned away from the more material struggles of human life, and have
set their hearts and minds on the knowledge of the Eternal.
CHAPTER III.
_NATURE’S REVENGES: THE SLEEPING SICKNESS._
Among the strange and mysterious diseases to which mankind is
subject in regions less familiar to the civilised world than Western
Europe, none is stranger or more appalling in its quiet, inexorable
deadliness than the Sleeping Sickness of the West African coast.
Apparently it has existed among the natives of that region from
time immemorial; but the first printed record we have of it is due
to Winterbottom, who, writing in 1803 of Sierra Leone, said, “The
Africans are very subject to a species of lethargy which they are
much afraid of, as it proves fatal in every instance.” One of the
latest notices of the disease, before it became the subject of active
investigation within the last five years, is that of Miss Kingsley,
who saw a few cases near the Congo estuary, but, though she was
impressed by the mysterious fatality of the disease, she did not
describe it as very prevalent or as a general source of danger to
life. The opening up of the Congo basin and increased familiarity
with the inner lands of the West African coast have shown that this
disease is widely scattered--though rarely so abundant as to be a
serious scourge--through the whole of tropical West Africa. Writers
in the early part of the last century described the disease as
occurring in the West Indies and in Brazil. Its presence was almost
certainly due, in those days of the slave trade, to the importation
of negroes already infected with the disease; and a curious theory
obtained some favour, according to which the sleeping sickness of
the West Indian slaves was a kind of nostalgia, and, in fact, the
manifestation of what is sometimes called “a broken heart.”
The signs that a patient has contracted the disease are very obvious.
They are recognised by the black people, and the certainly fatal
issue accepted with calm acquiescence. The usually intelligent
expression of the healthy negro is replaced by a dull apathetic
appearance; and there is a varying amount of fever and headache.
This may last for some weeks but is followed more or less rapidly
by a difficulty in locomotion and speech, a trembling of the tongue
and hands. There is increased fever and constant drowsiness, from
which the patient is roused only to take food. At last--usually after
some three or four months of illness--complete somnolence sets in;
no food is taken; the body becomes emaciated and ulcerated; and the
victim dies in a state of coma. The course of the disease, from the
time when the apathetic stage is first noticed, may last from two to
twelve months.
It is this terrible disease which has lately appeared on the shores
of the Victoria Nyanza, in the kingdom of Uganda, administered by
the British Government. Until the early part of the year 1901 there
was not the slightest suspicion that sleeping sickness occurred
in any part of the Uganda Protectorate; nor was it known in East
Africa at all, any more than in the north and south of that great
continent. It seems gradually to have crept up the newly opened
trade-routes of the Congo basin, and thence to have spread into the
west of Uganda, the territory known as Busoga. Numbers of Soudanese
and Congo men are known to have settled in this region after the
death of Emin Pasha. First noticed in 1901, it was estimated in
June 1902, by the Commissioner of Uganda, writing officially to the
Marquess of Lansdowne, that 20,000 persons had died of this disease
in the district of Busoga alone, and several thousands in the more
eastern portion of Uganda. At this moment it is probable that the
number of deaths in this region due to sleeping sickness since 1901
amounts to more than 200,000; and this though, most fortunately,
the disease has not yet spread eastward from Uganda into British
East Africa,[23] nor, so far as has been reported, down the Nile. No
curative treatment for the disease has yet been discovered; nor is
there any authenticated instance of recovery.
The appalling mortality produced by this disease in Central Africa
naturally caused the greatest anxiety to his Majesty’s Government,
which had but just completed the railway from the East Coast to the
shores of lake Victoria Nyanza, and had established a prosperous and
happy rule in that densely populated region. The official medical
men on the spot, though capable and experienced practitioners,
were unable to cope with this new and virulent outbreak. The
Foreign Office, having no imperial board of hygiene and medical
administration to apply to in this country, sought the assistance of
the Royal Society of London.
A committee of that society had already undertaken the study of
malaria at the request of the Secretary of State for the Colonies,
and had sent out young medical men as a commission to make certain
enquiries and experiments on that subject and report to the
committee in London. The sleeping sickness enquiry was undertaken
by the same committee; but unfortunately very insufficient funds
were placed at its disposal. When the South African cattle-owners
found their herds threatened six years ago by a new form of mortal
disease--‘the East Coast fever’--the South African Government
accepted the offer of Dr. Robert Koch, of Berlin, to undertake the
investigation of the disease and the discovery, if possible, of a
remedy, for the sum of £10,000. No such sum was at the disposal
of the committee of the Royal Society. They were obliged to send
out young and enterprising medical men, practically without pay or
reward, to see what they could do in the way of determining the cause
of, and, if possible, the remedy for, the terrible sleeping sickness
raging in Uganda and destroying daily hundreds of British subjects.
The committee set to work in the summer of 1902, and sent out Drs.
Low, Christy, and Castellani to Entebbe, the capital of Uganda.
The guesses as to the cause and nature of sleeping sickness at the
time when this commission set forth were very various. Some highly
capable medical authorities held that it was due to poisonous food.
The root of the manioc, on which the natives feed, was supposed to
become infected by some poison-producing ferment. A more generally
received opinion was that it was caused by a specific bacterium which
invades the tissues of the brain and spinal cord. Several totally
different micro-organisms of this sort had been described with equal
confidence by French and Portuguese investigators as the cause of the
sleeping sickness studied by them in West Africa or on the Congo. Sir
Patrick Manson, the head of the British Colonial medical service, an
authority of great experience in tropical disease, had put forward
the suggestion that the sleeping sickness was due to the infection
of the patient by a minute thread worm (allied to the ‘vinegar-eel,’
and one of a great class of parasites) which he had discovered in the
blood of negroes and had named _Filaria perstans_.
The occurrence of minute worms (true worms, neither unicellular
plants nor protozoa) in the blood of man was first made known by Dr.
Timothy Lewis, who described the _Filaria sanguinis hominis_, as well
as some other most important blood-parasites, some years ago (1878),
when officially engaged in an enquiry into the cause of cholera in
Calcutta. Subsequently, in China, Manson found that these little
blood-worms were sucked up by mosquitoes when gorging themselves
on the blood of a patient. It is, indeed, difficult to imagine
how they should escape passing into the mosquito with the blood.
Manson suggested that the minute worms (known to be the embryos of
a worm which, when adult, is about one fifteenth of an inch long)
are obliged to pass through a mosquito in order to accomplish their
development; but no proof of this suggestion has ever been made.
We know by abundant and repeated demonstration and experiment that
another blood-parasite--the malaria parasite--must pass through a
mosquito, in whose body it develops, and by which it is carried to a
new victim of infection. This was suspected long ago by both peasants
and doctors, and experimentally proved by Ross; but no such proof
has been given of the relation of Lewis’s blood-worm to a mosquito.
The so-called _Filaria perstans_, discovered by Manson in the blood
of negroes, appears to be very different from the _Filaria sanguinis
hominis_ of Lewis. It is not known how it gets into the blood; and
it is very astonishing, and much to be regretted, that none of the
medical men who have had it under observation have given a proper
anatomical account of it. It appears that this worm is very common
in the blood of negroes in tropical Africa; and as it was found
in several cases in the blood of individuals attacked by sleeping
sickness, Sir Patrick Manson was justified in entertaining the view
that this parasite was the cause of the disease.
One of the first results obtained by the commission sent by the Royal
Society committee to Uganda was the proof--which had, indeed, been
already furnished by the resident medical officers of the Uganda
Protectorate--that _Filaria perstans_, though remarkably abundant
in the blood of the negroes of Uganda, can have nothing to do with
sleeping sickness, since, though it often occurs in persons attacked
with that disease, it also exists in districts where sleeping
sickness is unknown; and, further, many cases of sleeping sickness
have been observed in which no _Filaria perstans_ has been discovered
in the blood or other parts of the body.
While Drs. Low and Christy occupied themselves with settling
this question as to the connexion of _Filaria perstans_ with the
disease and carried out a careful study of its clinical aspects,
Dr. Castellani examined the brain and spinal cord of those who
died from sleeping sickness, for bacteria. He found again and
again an extremely minute globular vegetable parasite--of the kind
known as streptococcus--which he concluded to be the cause of the
disease, although he had not produced the disease experimentally by
inoculating an animal with this microbe.
In the early part of 1903 these were the only results obtained by
some six months’ work of the medical men sent out by the Royal
Society’s committee; and it was felt that something more must be
done. The investigation of a disease hitherto little known and
studied is one of the most difficult tasks in the world, requiring
the highest scientific qualities. Any serious attempt to deal with
the sleeping sickness in Uganda would, it was at length recognised,
require the dispatch of a man of proved capacity and experience,
provided with full powers and with trained men as his assistants. No
such men are provided by the public service of the British Empire.
To detach a medical man of recognised insight and experimental skill
from his practice--even were it possible to find one specially
qualified for the present enquiry--would involve the payment of a
large fee, which neither the Royal Society nor the Foreign Office
could command.
What, then, was to be done? Fortunately there was one man in the
public service, recently appointed to be one of the chiefs of the
educational arrangements of the Army Medical Department, who had
shown himself to be especially gifted in the investigation of
obscure diseases. This was Colonel David Bruce, F.R.S., who, some
fifteen years ago, established the existence of Malta fever, as
an independent disease, by his clinical observations and by the
isolation and cultivation of the parasitic bacterium causing it;
and who, further, when employed by the governor of Zululand a few
years later (1895) to investigate the celebrated tsetze-fly disease
of South Africa, had discovered, contrary to the assertions and
prejudices of a large number of African sportsmen and explorers, that
the horse and cattle disease known as nagana or tsetze-fly disease
was due to the presence in the blood of the affected animals of a
peculiar cork-screw-like animal parasite, the _Trypanosoma Brucei_.
This is carried by the bite of the tsetze-fly from the blood of wild
game, such as buffalo and antelope, where it does no harm, to the
blood of domesticated animals, in which it multiplies and proves to
be the source of a deadly poison causing death in a few weeks. The
experiments by which Colonel Bruce demonstrated this relationship of
tsetze-fly, trypanosome parasite, wild big game, and domesticated
animals, were universally regarded as masterly both in conception and
execution, and absolutely conclusive.
The committee of the Royal Society came to the conclusion that the
thing to be done was to get Colonel Bruce to consent to proceed
to Uganda, and to recommend the Foreign Office to obtain from the
War Office the temporary detachment of Colonel Bruce for this
service. Accordingly Colonel Bruce arrived in Uganda in the middle
of March, 1903. Dr. Low and Dr. Christy had already departed,
but Dr. Castellani was still at Entebbe engaged in the study of
his streptococcus. He mentioned to Colonel Bruce on his arrival
that he had on more than one occasion seen a trypanosome in the
cerebro-spinal fluid of negroes suffering from sleeping sickness;
but, inasmuch as Dutton on the West Coast and Hodges in Uganda had
described a trypanosome as an occasional parasite in human blood,
he had not considered its occurrence in sleeping-sickness patients
as of any more significance than is the occurrence of _Filaria
perstans_. Castellani regarded the trypanosome, like the filaria,
as a mere accidental concomitant of sleeping sickness, the cause of
which he considered to be the bacterial streptococcus which he had so
frequently found to be present.
Naturally enough, Bruce was impressed by the fact that trypanosomes,
of the deadly nature of which he had had ample experience, had been
found, even once, in the cerebro-spinal fluid of sleeping-sickness
patients; and he immediately set to work to make a thorough search
for this parasite in all the cases of sleeping sickness; then under
observation at Entebbe. He generously allowed Castellani to take
part in the investigation, which resulted in the immediate discovery
of the trypanosome in the cerebro-spinal fluid of twenty cases, out
of thirty-four examined, of negroes afflicted with the disease;
whilst in twelve negroes free from sleeping sickness the trypanosome
could not be found in the cerebro-spinal fluid. Castellani returned
to Europe three weeks after Bruce’s experiments were commenced, and
announced the discovery, which has been, in consequence, erroneously
attributed to him, although mainly due to Bruce.
Bruce continued his work in Uganda until the end of August, 1903,
having been joined there by Colonel Greig of the Indian Army, who
has continued the work of the Royal Society’s commission since Bruce
left. Other valuable observations have been carried out by various
medical men officially connected with the Uganda Protectorate.
Bruce soon showed that in every case of sleeping sickness, when
examined with sufficient care, the trypanosome parasite is found to
be present in the cerebro-spinal fluid. He also showed that it is
absent from that fluid in all negroes examined who were not afflicted
with the disease, but made the very important discovery that the
trypanosome is present in the blood (not the cerebro-spinal fluid)
of twenty-eight per cent. of the population in those areas where
sleeping sickness occurs, the persons thus affected having none of
the symptoms of sleeping sickness, but being either perfectly healthy
or merely troubled with a little occasional fever. The subsequent
history of all the cases thus observed has not as yet been recorded.
But in many such, even in some Europeans, the earlier presence of
the trypanosome in the blood has been followed by its entry into the
cerebro-spinal lymphatics, and by the fatal development of sleeping
sickness.
As already indicated, it was found by Bruce, on recording the cases
of sleeping sickness brought into or reported in Entebbe, that there
were certain “sleeping-sickness areas” and other areas free from
sleeping sickness. The theory now took shape in Bruce’s mind that
the trypanosome first gets into the blood, and then after a time,
makes its way into the cerebro-spinal system, only then producing
its deadly symptoms. Very generally, when once in the blood, the
trypanosome multiplies itself, and sooner or later--apparently,
in some cases, even after two or three years--gets into the
cerebro-spinal fluid. It is probable that it may be destroyed by
natural processes in the human body before this final stage is
reached; and thus the infected person may recover and escape the
deadly phase of the disease. But nothing certain is known, as yet,
on this head. Later observations show that the trypanosome is found
alive and in large quantity in the lymphatic glands, especially those
in the region of the neck in infected persons. These glands were
known to be enlarged in persons suffering from the disease.
Colonel Bruce’s next step was to ascertain the mode in which the
trypanosome is introduced into the blood. Naturally he looked for a
kind of tsetze fly, such as carries the trypanosome in the nagana
disease of horses and cattle already studied by him in Zululand. It
is a fact that the _Glossina morsitans_ and _Glossina pallidipes_,
which are the tsetze flies of the “fly-districts” where nagana
disease is rife, are unknown in Central or Western Africa; and
also it is a fact that no tsetze fly had been observed in the
neighbourhood of the Victoria Nyanza when Colonel Bruce began his
enquiries. He employed, through the good-will of the native chiefs
and rulers, a large number of natives to collect flies throughout
the country forming a belt of twenty or thirty miles around the north
of the lake. Many thousands of flies were thus brought in, and the
localities from which they came carefully noted. Among these flies
Colonel Bruce recognised a tsetze fly; and when these collections
were received at the Natural History Museum in London, it was at once
determined by Mr. Austen, the assistant in charge of our collections
of Diptera (or two-winged flies), that the Uganda tsetze fly was
not the same species as that of Zululand and the fly country, but
a distinct species previously known only on the West Coast and the
Congo basin, and described by the name _Glossina palpalis_. The
story thus developed itself: the trypanosome of sleeping sickness
is probably carried by this West Coast tsetze fly just as the
trypanosome of nagana is carried in the south-east of Africa by the
_Glossina morsitans_ and _pallidipes_, the regular and original
“tsetze” flies.
Sleeping sickness thus presented itself as a special kind of human
tsetze-fly disease. To test this hypothesis, Colonel Bruce pursued
two very important and distinct lines of enquiry. In the first
place he found that those places on his map which were marked as
“sleeping-sickness areas” were precisely those places from which the
collected flies included specimens of tsetze fly, whilst he found
that there were no tsetze flies in the collections of flies brought
in by the natives from the regions where there was no sleeping
sickness.
His second test inquiry consisted in ascertaining whether the tsetze
flies of Uganda are actually found, experimentally, to be capable
of carrying the trypanosome from one infected person to another.
For this purpose it was necessary to make use of monkeys, certain
species of which were ascertained to be liable to the infection
of the sleeping sickness trypanosome when this was introduced by
means of injection through a syringe. Such monkeys were found to
develop the chief symptoms of sleeping sickness, and ultimately
died of the disease, their cerebro-spinal fluid being invaded by
the parasites. Accordingly it was possible to use monkeys as test
animals. It was found by Colonel Bruce that tsetze flies (_Glossina
palpalis_) which had been made to bite infected negroes could carry
the infection to the monkeys; and it was also found that even when
a number of tsetze flies, not specially prepared, were allowed to
bite a monkey, the latter eventually developed the trypanosome in its
blood and cerebro-spinal fluid, thus showing that the tsetze flies,
as naturally occurring in the country around Entebbe, contain many of
them, the trypanosome ready to pass from the fly to a human or simian
victim, when casually bitten by the fly.
Experiments such as these of infection by the fly, and the use of
monkeys in the research, require very great care; and it is quite
reasonable to ask that they shall be repeated and most carefully
checked before they are considered as demonstrative and absolutely
certain. It may, however, be considered as practically certain that
the sleeping sickness is due to the presence in the cerebro-spinal
fluid of quantities of a minute parasite, the _Trypanosoma
Gambiense_, which is carried from man to man by the _palpalis_ tsetze
fly, which sucks it up from the blood of an infected individual and
conveys it to previously uninfected individuals. The natives in
Uganda lie about and sleep under the shade of trees where the tsetze
flies are especially abundant; and they are quite indifferent to the
bites of flies of one kind and another.
It is the dislike to the mere touch of a fly, still more to its bite,
which has protected Europeans almost entirely from the sleeping
sickness. Unfortunately there is no immunity for Europeans in the
matter; and the existence of half a dozen or more cases of white
people infected with the trypanosome, who have ultimately died in
England or elsewhere in Europe from sleeping-sickness contracted
through the bite of a fly in Africa, is abundant proof that there is
not, as has been supposed, any special freedom from the disease for
white people.[24]
The foregoing description of the nature and mode of the infection
of sleeping sickness will not cause any astonishment to the layman
of the present day who knows anything of recent medical science. We
are all familiar with the danger of fly-bites, even in this country,
where deadly bacteria are occasionally carried by biting flies, such
as the horse-flies, into the human subject; and nowadays every one is
more or less familiar with the discovery of the minute blood-parasite
which causes malaria or ague and is carried by a particular kind
of gnat in the interior of which it multiplies by a process of
sexual conjugation. At the same time the reader who is interested in
sleeping sickness will probably desire to know more about the nature
of the tsetze flies and some further details as to the parasite
spoken of as trypanosome.
[Illustration: FIG. 48.
Tsetze flies--_Glossina morsitans_--magnified two diameters. This
is the “fly” of the Nagana or horse and cattle disease of South
Africa. The _Glossina palpalis_, which carries the _Trypanosoma
Gambiense_ causing sleeping sickness, is very closely similar to
it in appearance.]
The tsetze flies form a genus called by Wiedemann (in 1830)
“Glossina.” They are only found in Africa; and some seven species
in all are known. They are little bigger than a common house-fly,
and much like it in colour (fig. 48). They differ in appearance
from the house-fly in the fact that the wings, when the insect is
at rest, are parallel to one another, and slightly over-lap in the
middle line, instead being to a small extent divergent at their free
extremities. The bite, like that of all flies, is rather a stab than
a bite, and is effected by a beak-like process of the head, the blood
of the animal pricked in this way being drawn into the fly’s mouth
by a sucking action of the gullet. The tsetze flies appear to be
especially greedy and are said to gorge themselves to such an extent
that the blood taken in from one animal overflows the gullet, and
so contaminates the wound inflicted by the fly on the next animal
it visits. It is at the present moment assumed very generally that
this is the way in which infection is produced. But it is not at all
improbable that the trypanosome undergoes some kind of multiplication
and change of form when sucked into the tsetze fly as happens in the
case of the malaria parasite when swallowed by the _Anopheles_ gnat.
No such change has yet been discovered in regard to the trypanosome
of sleeping sickness: but it cannot be said that the matter has been
exhaustively studied, or that a negative conclusion is justified.[25]
[Illustration: FIG. 49.
The earliest discovered Trypanosome, described by Gruby in 1843
as “_Trypanosoma sanguinis_” and found by him in the blood of the
common esculent Frog.
It was not noticed again until it was re-discovered by Lankester
in 1871, who published the above figure of it in the _Quarterly
Journal of Microscopical Science_ in that year.]
As to the parasite itself--the trypanosome--a long and very
interesting story has now to be told. The first blood-parasite ever
made known to naturalists and medical men was that to which Gruby,
in 1843, gave the name _Trypanosoma sanguinis_. He found it in the
blood of the common frog. We have here reproduced a figure of this
original trypanosome (fig. 49). Similar parasites had been seen, but
not named, in the blood of fishes. These trypanosomes are all very
minute and of a somewhat elongated form, a fair average length being
one thousandth of an inch. They are simple protoplasmic animals,
consisting of one single nucleated corpuscle. The protoplasm is
drawn out at one end of the creature into a motile undulating thread,
and from the point where this joins the body a membranous undulating
crest extends along the greater part of the animal’s length. There
is no mouth, nutrition being effected by the imbibition of soluble
nutrient matter.
After a long interval Gruby’s trypanosome was re-discovered in 1871;
and then several kinds were described in the blood of tortoises,
fishes and birds. In 1878, Dr. Timothy Lewis found a parasite in the
blood of rats, at first in India, and subsequently in the common
rats of London sewers. This parasite resembles a trypanosome in
many respects (fig. 46A), but was very properly given a distinct
name by Savile Kent, who called it “Herpetomonas.” This name has,
however, been dropped; and the rat’s-blood parasite is spoken of as
a trypanosome. It is the _Trypanosoma Lewisii_, and was the first of
these trypanosomes to be found in the blood of a mammalian animal.
The _Trypanosoma Lewisii_ of the rat’s blood seems to do no harm
to the rat, in which it swarms, multiplying itself by longitudinal
fission; nor is it at present known to produce any trouble in other
animals when transferred to their blood. Similarly, the frog’s
trypanosome seems to exist innocently in the frog’s blood.
The next trypanosome discovered (1880) was, however found in the
blood of camels, horses, and cattle suffering from a deadly disease
known in India by the name “surra.” It is called _Trypanosoma
Evansii_, after the observer who detected it. Trypanosomes now began
to get a bad name, for the next was discovered in animals afflicted
by a North African disease known to French veterinaries as “dourine.”
This trypanosome was called _T. equiperdum_.
A little later, namely, in the year 1895, came Bruce’s discovery of
a trypanosome associated with a tsetze fly in the production of the
terrible nagana disease of the “fly-belts” of South Africa, which
renders whole territories impassable for horses or cattle (fig.
46B). The remarkable and important observation was made by Bruce
that this trypanosome (known as _T. Brucei_) inhabits the blood
of big game without injuring them, just as the rat’s trypanosome
inhabits the rat’s blood without producing disease; and that it is
only when the trypanosome is carried from these natural wild “hosts”
to domesticated animals introduced by man, such as horses asses,
cattle, and dogs, that disease results. The wild animals are “immune”
to Bruce’s trypanosome; the introduced animals are poisoned by the
products of its growth and fissile multiplication in their blood.
Since Bruce’s researches on nagana, a trypanosome, _T. equinum_ (fig.
46D), has been discovered in the horse-ranches of South America,
where it causes deadly disease, the _mal de caderas_, among the
collected horses; and a curiously large-sized trypanosome has been
found by Theiler in the blood of cattle in the Transvaal. Down to
a recent date no trypanosome had been found in the blood of man;
and indeed it is almost certain that none of the kinds hitherto
mentioned can survive in his blood. But in 1902 Dutton discovered
a trypanosome in the blood of a West African patient; and a few
other cases were noted. This trypanosome of human blood was called
by Dutton _T. Gambiense_. It was not found to be connected with any
serious symptoms, a little fever being the only disturbance noted.
It now, however, appears that this trypanosome in the blood is the
preliminary stage of the infection which ends in sleeping sickness;
and, as we have seen, in a population seriously attacked by sleeping
sickness, as is that of Uganda, as many as 28 per cent. of the people
have trypanosomes in their blood.
There is no ground at present known for distinguishing Dutton’s
_T. Gambiense_ of human blood from that which Bruce has found to
be so terribly abundant in Uganda, and to be the cause of sleeping
sickness. Indeed all the trypanosomes of the blood of the larger
mammalia are singularly alike in appearance; and the figure which is
here given (fig. 50) of the trypanosome of sleeping sickness (_T.
Gambiense_) might quite well serve to represent the _T. Evansii_ of
surra disease, the _T. Brucei_ of nagana disease, or the _T. equinum_
of the South American _mal de caderas_.
[Illustration: FIG. 50.
_Trypanosome Gambiense_, from the blood of men suffering from the
early symptoms of sleeping sickness. A, after Bruce and Navarro;
B, after Castellani. They show a large oval nucleus (drawn as a
black mass), and a small black “micronucleus,” or “blepharoplast”
in front.]
A most characteristic feature, which has been made out by the careful
study of these trypanosomes by means of colouring reagents and very
high powers of the microscope, is that, whilst there is a large
granular nucleus there is also a small body at the anterior end of
the animalcule which readily stains and is placed at the end of the
root (so to speak) of the vibratile _flagellum_ or free thread.
This smaller nucleus has been variously called the “micronucleus,”
the “centrosome,” and the “blepharoplast.” It is identical with a
structure similarly placed in non-parasitic microscopic animals
to which trypanosoma is undoubtedly related. We find it in the
phosphorescent noctiluca of our seas, and in various animalcules
called “Flagellata.”
[Illustration: FIG. 51.
The Trypanosome (_T. equiperdum_) of the disease called
“Dourine,” as seen alive in the blood of a rat, eight days after
inoculation.
A, the actively wriggling cork-screw-like parasites; B, the
blood-corpuscles of the rat. This figure, of comparatively low
magnification, gives an indication of the relative size of the
parasites and the blood-corpuscles.
The blood-corpuscles are about 1/5000th of an inch each in
diameter.]
The creature drawn in our fig. 50 is, then, the typical trypanosome.
It is this which the medical investigator looks for in his human
or animal patients; it is this which he has regarded as the sign
and proof of infection. Experiments have shown that, though so much
alike in appearance in the different diseases we have named, yet each
trypanosome has its own properties. Human blood-serum is poisonous
to one and not to another; an animal immune to one is not immune
to another. At present no treatment has been discovered which will
destroy the parasites when once they have effected a lodgment, or
act as an antidote to the poison which they produce in the infected
animal or man. But the fact that in some cases an animal may become
immune to the attack of the parasite which usually is deadly to its
kind, gives hope of an eventual curative treatment for trypanosome
infection; as does also the fact that the serum of some animals acts
as a poison to trypanosomes which flourish in other animals.
With regard to immunity, it must always be remembered that we are
liable to confuse two different conditions under this one term.
An animal may be said to be immune to blood-parasite because that
parasite is actually unable to live in its blood. On the other
hand an animal is often said to be immune to a parasite when the
parasite can and does flourish in its blood or tissues but produces
no poisonous effect. A more precise nomenclature would describe the
attacked organism in the first case as “repellent,” for it repels
the parasite altogether; in the second case as “tolerant,” for it
tolerates the presence and multiplication of the parasite without
suffering by it.
We have yet to learn a good deal more as to the repulsion and the
toleration of the trypanosome parasites by mammals and man. Still
more have we to learn about the life-history of the trypanosome. At
the moment of writing, absolutely nothing has been ascertained as to
the life-history of the trypanosome of mammalian blood, except that
they multiply in the blood by longitudinal fission. Our ignorance
about them is all the more serious since other trypanosomes,
discovered by Danilewesky in birds, have been studied and have been
shown to go through the most varied phases of multiplication and
change of size and shape, including a process of sexual fertilisation
like that of the malaria parasite, to which, indeed, it now seems
certain the trypanosomes are very closely allied.
It is to Dr. Schaudinn[26], that we owe a knowledge of some most
extraordinary and important facts with regard to the trypanosomes
parasitic in the blood of the little stone-owl of southern Europe
(_Athene noctua_). These facts are so remarkable that, were Dr.
Schaudinn not known as a very competent investigator of microscopic
organisms we should hesitate to accept them as true. Supposing, as
is not improbable, that similar facts can be shown in regard to the
trypanosomes of mammalian blood, the conclusions which our medical
investigators have based upon a very limited knowledge of the form
and life-history of the trypanosomes occurring in diseases such
as sleeping sickness, surra, and nagana, are likely to be gravely
modified, and practical issues of an unexpected kind will be involved.
As has already been pointed out in this article, the British
Government has no staff of public servants trained to deal with the
world-wide problems of sanitation and disease which necessarily
come with increasing frequency before the puzzled administrators
of our scattered Empire. There is no provision for the study of
the nature and history of blood-parasites in this country, that
is to say, no provision of laboratories with the very ablest and
exceptionally-gifted investigators at their head[27]. We play with
the provision of an adequate army, officers, and equipment to fight
disease, which annually destroys hundreds of thousands of our people,
much as barbarous states or bankrupt European kingdoms play with
the provision of an ordinary army and navy. Their forces exist on
paper, or even in fact, but have no ammunition, no officers, and no
information; and there is no pay for the soldiers or sailors. Dr.
Schaudinn, on the other hand, carried on his researches as an officer
of the German Imperial Health Bureau of Berlin; and the account
of them was published in the official Report of that important
department of the German imperial administrative service three years
ago.
[Illustration: FIG. 52.
_Trypanosoma Ziemanni_, from the gut of the gnat (_Culex_),
having been sucked in with the blood of the owl (_Athene
noctua_). A, fertilized vermiform stage. B, multiplication of
nucleus. C, elongation and coiling, with increase of nuclei
(_after_ Schaudinn).]
[Illustration: FIG. 53.
Minute neutral Trypanosomes in the gut of the gnat liberated from
the coiled form of Fig. 52, C (_after_ Schaudinn).]
It is not possible here to give a full report on Dr. Schaudinn’s
work; but it appears that he has studied two distinct species of
trypanosoma, both occurring side by side in the blood of the little
stone-owl, and already seen but incompletely studied, by Danilewsky
and Ziemann. The second of the two species of trypanosome is in
some respects the more remarkable. Schaudinn calls it _Trypanosoma
Ziemanni_; and from the figures which are here given (figs. 4, 5,
6, and 7), copied from his article, with the explanations below
the figures, the reader will at once see what an extraordinary
range of form and mode of multiplication is presented by this one
species of trypanosome. Space will not permit us to comment on these
various phases beyond noting how assuredly such forms would have
escaped recognition as belonging to the trypanosome history if seen,
before Dr. Schaudinn’s memoir was printed, by any of our medical
commissioners blindly exploring round about the diseases caused by
trypanosomes in man and mammals.
[Illustration: FIG. 54.
A, B, C, D, Elongated spiral forms of _Trypanosoma Ziemanni_
(some intertwined) developed from those of Fig. 53--showing
transverse division, nucleus, and blepharoplast.
E, F, pear-shaped forms resulting from the contraction of forms
like A; G, a cluster of very minute individuals.
These forms are observed in the gnat and also in the blood of
the owl, into which they pass when the gnat bites that bird, and
there give rise to the large male and female Trypanosomes seen in
Fig. 55 (_after_ Schaudinn).]
One very astonishing and revolutionary fact discovered by Schaudinn
we must, however, especially point out. Medical men have long been
acquainted with the spirillum, or spiral threads, discovered by
Obermeyer in the blood of patients suffering from the relapsing
fever of eastern Europe. These were universally and without question
regarded as Bacteria (vegetable organisms) and referred to the genus
“Spirochæta” of Ehrenberg. They were called _Spirochæta Obermeieri_;
and relapsing fever was held to be a typical case of a bacterial
infection of the blood. It is now shown by Schaudinn that the
blood-parasite spirochæta is a phase of a trypanosome (fig. 54);
that it has a large nucleus and a micronucleus or blepharoplast,
neither of which are present in the spiral Bacteria; and, further,
that it alters its shape, contracting so as to present the form
of minute oval or pear-shaped bodies, each provided with a larger
and a smaller nucleus (fig. 54, E, F). These oval bodies are often
engulfed by the colourless corpuscles (phagocytes) of the blood;
and it is in the highest degree probable that in this condition
they have been observed in some tropical diseases without their
relation to the spiral forms being suspected. The corpuscles lately
described by Leishman, in cases of a peculiar Indian fever, are
very probably of this nature, as are also similar bodies recently
described in Delhi sore. On the whole, it may safely be said that the
researches of Dr. Schaudinn, of which only a preliminary account has
yet been published, have widely modified our conceptions as to these
blood-parasites, and must lead to important discoveries in regard to
diseases caused by them in mammals and in man.
[Illustration: FIG. 55.
_Trypanosoma Ziemanni_, from the blood of the little owl. The
stages shown in Figs. 52-54 are passed inside the gnat. The
spiral and pear-shaped bodies of Fig. 54 pass from the gnat’s
proboscis into the blood of the little owl, and grow there into
the large forms here figured. A, B, and C are females, destined
to be fertilized by spermatozoa (see Fig. 21) when swallowed by
a gnat. D and E are male Trypanosomes, which will give rise each
to eight fertilizing individuals or spermatozoa as shown in Fig.
56--when swallowed by a gnat.]
The facts that wild game serve as a tolerant reservoir of
trypanosomes for the infection of domesticated animals by the
intermediary of the tsetze fly, and that native children in
malarial regions act the same part for the malarial parasite and
mosquito, suggest very strongly that some tolerant reservoir of the
sleeping-sickness trypanosome may exist in the shape of a hitherto
unsuspected mammal, bird, or insect. The investigation of that
hypothesis and the discovery of the reproductive and secondary forms
of the mammalian trypanosomes are the matters which now most urgently
call for the efforts of capable medical officers. But we must not
be sanguine of rapid progress, since men of the scientific quality
needful for pursuing these enquiries are not numerous; and those who
exist are not endowed with private fortunes, as a rule. At the same
time no attempt is made by the British Government to take such men
into its pay, or to provide for the training and selection of such
officers.[28]
[Illustration: FIG. 56.
Male _Trypanosoma Ziemanni_, giving rise by nuclear division to
eight spermatozoa or microgametes. From the stomach of the gnat
(_Culex_).
Each of these penetrates and fuses with the substance of a female
Trypanosome, swallowed at the same time or already taken in by
the gnat. The fertilized animalculæ is the vermiform motile stage
of Fig. 52, A; and so we return to the starting-point of the
cycle (_after_ Schaudinn).]
The relations of parasites to the organisms upon or in which they are
parasitic, and the relation of man, once entered on the first steps
of his career of civilisation, to the world of parasites, form one of
the most instructive and fascinating chapters of natural history. It
cannot be fully written yet, but already some of the conclusions to
which the student is led in examining this subject have far-reaching
importance and touch upon great general principles in an unexpected
manner.
Before the arrival of man--the would-be controller, the disturber
of Nature--the adjustment of living things to their surrounding
conditions and to one another has a certain appearance of perfection.
Natural selection and the survival of the fittest in the struggle
for existence lead to the production of a degree of efficiency and
harmonious interaction of the units of the living world, which,
being based on the inexorable destruction of what is inadequate and
inharmonious as soon as it appears, result in a smooth and orderly
working of the great machine, and the continuance by heredity of
efficiency and a high degree of individual perfection.
Parasites, whether microscopic or of larger size, are not, in such
circumstances, the cause of widespread disease or suffering. The
weakly members of a species may be destroyed by parasites, as others
are destroyed by beasts of prey; but the general community of the
species, thus weeded, is benefited by the operation. In the natural
world the inhabitants of areas bounded by sea, mountain, and river
become adjusted to one another; and a balance is established. The
only disturbing factors are exceptional seasons, unusual cold, wet,
or drought. Such recurrent factors may from time to time increase the
number of the weakly who are unable to cope with the invasions of
minute destructive parasites, and so reduce, even to extermination
the kinds of animals or plants especially susceptible to such
influences. But anything like the epidemic diseases of parasitic
origin with which civilised man is unhappily familiar seems to be due
either to his own restless and ignorant activity or, in his absence,
to great and probably somewhat sudden geological changes--changes of
the connexions, and therefore communications, of great land areas.
It is abundantly evident that animals or plants which have, by
long æons of selection and adaptation, become adjusted to the
parasites and the climatic conditions and the general company (so
to speak) of one continent may be totally unfit to cope with those
of another; just as the Martian giants of Mr. H. G. Wells, though
marvels of offensive and defensive development, were helpless in
the presence of mundane putrefactive bacteria and were rapidly and
surely destroyed by them. Accordingly, it is not improbable that such
geological changes as the junction of the North and South American
continents, of North and South Africa, and of various large islands
and neighbouring continents, have, in ages before the advent of
man, led to the development of disastrous epidemics. It is not a
far-fetched hypothesis that the disappearance of the whole equine
race from the American continent just before or coincidently with
the advent of man--a region where horses of all kinds had existed in
greater variety than in any other part of the world--is due to the
sudden introduction, by means of some geological change, of a deadly
parasite which spread as an epidemic and extinguished the entire
horse population.
Whatever may have happened in past geological epochs, by force of
great earth-movements which rapidly brought the adaptations of one
continent into contact with the parasites of another, it is quite
certain that man, proud man, ever since he has learnt to build
a ship, and even before that, when he made up his mind to march
aimlessly across continents till he could go no further, has played
havoc with himself and all sorts of his fellow-beings by mixing up
the products of one area with those of another. Nowhere has man
allowed himself--let alone other animals or even plants--to exist in
fixed local conditions to which he or they have become adjusted. With
ceaseless restlessness he has introduced men and beasts and plants
from one land to another. He has constantly migrated with his herds
and his horses, from continent to continent. Parasites, in themselves
beneficent purifiers of the race, have been thus converted into
terrible scourges and the agents of disease. Europeans are decimated
by the locally innocuous parasites of Africa; the South Sea islanders
are exterminated by the comparatively harmless measles of Europe.
A striking example of the disasters brought about by man’s blind
dealings with Nature--disasters which can and will hereafter be
avoided by the aid of science--is to be found in the history of
the insect phylloxera and the vine. In America the vine had become
adjusted to the phylloxera larvae, so that when they nibbled its
roots the American vine threw out new root-shoots and was none the
worse for the little visitor. Man in his blundering way introduced
the American vine, and with it the phylloxera, to Europe; and in
three years half the vines in France and Italy were destroyed by
the phylloxera, because the European vines had not been bred in
association with this little pest, and had not acquired the simple
adjusting faculty of throwing out new shoots.
But it is not only by his reckless mixing up of incompatibles from
all parts of the globe that the unscientific man has risked the
conversion of paradise into a desert. In his greedy efforts to
produce large quantities of animals and plants convenient for his
purposes, and in his eagerness to mass and organise his own race for
defence and conquest, man has accumulated unnatural swarms of one
species in field and ranch and unnatural crowds of his own kind in
towns and fortresses. Such undiluted masses of one organism serve as
a ready field for the propagation of previously rare and unimportant
parasites from individual to individual. Human epidemic diseases as
well as those of cattle and crops, are largely due to this unguarded
action of the unscientific man.
A good instance of this is seen in the history of the coffee
plantations of Ceylon, where a previously rare and obscure parasitic
fungus, leading an uneventful life in the tropical forests of that
country, suddenly found itself provided with an unlimited field
of growth and exuberance in the coffee plantations. The coffee
plantations were destroyed by this parasite, which has now returned
to its pristine obscurity. Disharmonious, blundering man was
responsible for its brief triumph and celebrity. Dame Nature had not
allowed the coffee fungus more than a very moderate scope. Man comes
in and takes the reins; disaster follows; and there is no possibility
of return to the old régime. Man must make his blunders and retrieve
them by further interference--by the full use of his intelligence, by
the continually increasing ingenuity of his control of the physical
world, which he has ventured to wrest from the old rule of natural
selection and adaptation.
The adjustment of all living things to their proper environment
is one of great delicacy and often of surprising limitation. In
no living things is this more remarkable than in parasites. The
relation of a parasite to the “host” or “hosts” in which it can
flourish (often the host is only one special species or even variety
of plant or animal) is illustrated by the more familiar restriction
of certain plants to a particular soil. Thus the Cornish heath only
grows on soil overlying the chemically peculiar serpentine rocks
of Cornwall. The two common parasitic tape-worms of man pass their
early life the one in the pig and the other in bovine animals. But
that which requires the pig as its first host (_Tænia solium_) cannot
use a bovine animal as a substitute; nor can the other (_Tænia
mediocanellata_) exist in a pig. Yet the difference of porcine and
bovine flesh and juices is not a very patent one; it is one of small
variations in highly complex organic chemical substances. A big
earth-worm-like stomach-worm flourishes in man, and another kind
similar to it in the horse. But that frequenting man cannot exist in
the horse, nor that of the horse in man. Simpler parasites, such as
are the moulds, bacteria, and again the blood-parasites, trypanosoma,
etc., exhibit absolute restrictions as to the hosts in which they can
or can not flourish without showing specific changes in their vital
processes. Being far simpler in structure than the parasitic worms,
they have less “mechanism” at their disposal for bringing about
adjustment to varied conditions of life. The microscopic parasites
do not submit to alterations in the chemical character of their
surroundings without themselves reacting and showing changed chemical
activities. A change of soil (that is to say of host) may destroy
them; but, on the other hand, it may lead to increased vigour and the
most unexpected reaction on their part in the production of virulent
chemical poisons.
We are justified in believing that until man introduced his
artificially selected and transported breeds of cattle and horses
into Africa there was no nagana disease. The _Trypanosoma Brucei_
lived in the blood of the big game in perfect harmony with its
host. So, too, it is probable that the sleeping-sickness parasite
flourished innocently in a state of adjustment due to tolerance on
the part of the aboriginal men and animals of West Africa. It was not
until the Arab slave raiders, European explorers, and indiarubber
thieves stirred up the quiet populations of Central Africa, and mixed
by their violence the susceptible with the tolerant races, that the
sleeping-sickness parasite became a deadly scourge--a “disharmony” to
use the suggestive term introduced by my friend Elias Metschnikow.
The adjustment of primaeval populations to their conditions has also
been broken down by “disharmonies” of another kind, due to man’s
restless invention, as explained a few years ago in the interesting
book of Mr. Archdall Reid on the “Present Evolution of Man.” Not
only does the human race within given areas become adjusted to a
variety of local parasites, but it acquires a tolerance of dangerous
drugs, such as alcohol and opium, extracted by man’s ingenuity from
materials upon which he operates. A race thus provided and thus
immune imposes, by its restless migrations, on unaccustomed races the
deadly poisons to the consumption of which it is itself habituated.
The unaccustomed races are deteriorated or even exterminated by the
poisons thus introduced.
Infectious disease, it was long ago pointed out, must be studied
from three main points of view: (1) the life history and nature
of the disease-germ or infective matter; (2) the infected subject,
his repellant or tolerant possibilities, and his predisposition or
receptivity; (3) the intermediary or carrying agents. Whilst it is
true that little or nothing has been done by the State in acquiring
or making use of knowledge as to the first and second of these
factors, with a view to controlling the spread of disease, it is
the fact that much has been done both in the way of investigation
and administration in relation to the third factor. The great
public-health enquiries and consequent legislation in this country,
in which scientific men of the highest qualifications, such as
Simon, Farr, Chadwick, and Parkes, took part during the Victorian
period, have had excellent results; to them are due the vast
expenditure at the present day on pure water, sewage disposal, and
sanitary inspection. But little or nothing has been done in regard
to the first and second divisions of the subject, in which the less
organised portions of the British Empire are more deeply concerned
than in waterworks and sewer-pipes. It is still contested whether
leprosy (which is a serious scourge in the British Empire, though
expelled from our own islands) is a matter of predisposition caused
by diet or solely due to contagion; and yet it is left to individual
practitioners to work out the problem. The State prepares vaccine
lymph in a cheap and unsatisfactory way for the use of its, till
recently, compulsorily vaccinated citizens; but the State, though
thus interfering in the matter of vaccine, has spent no money to
study effectively and so to improve the system of vaccination. Here
and there some temporary and ineffective enquiry has been subsidised
by a Government office; but there is no great army of investigators
working in the best possible laboratories, led by the ablest minds
of the day, with the constant object of improving and developing in
new directions the system of inoculation. Surely if compulsion, or
every pressure short of compulsion, is justified in enforcing vaccine
inoculation on every British family, it would be only reasonable and
consistent to expend a million or so a year in the perfection and
intelligent control of this remedy by the most skilled investigators.
Yet not a halfpenny is spent by the British Government in this way.
Medicine is organised in this country by its practitioners as a
fee-paid profession; but as a necessary and invaluable branch of
the public service it is neglected, misunderstood, and rendered to
a large extent futile by inadequate funds and consequent lack of
capable leaders. The defiant desperate battle which civilised man
wages with Nature must go on; but man’s suffering and loss in the
struggle--the delay in his ultimate triumph--depend solely on how
much or how little the great civilised communities of the world seek
for increased knowledge of nature as the basis of their practical
administration and government.
POSTSCRIPT, December, 1906.--Messrs. Thomas and Breinl, of the
Liverpool School of Tropical Medicine, two years ago discovered
and published the fact that an arsenical aniline product known as
“atoxyl” when injected into patients suffering from Sleeping Sickness
destroys the parasite and promises to be a cure for this terrible
infection. Experiments are in progress in many quarters in regard to
this treatment, but certainty can only be arrived at by prolonged
observation of the patients. The newspapers have lately, in error,
attributed this discovery to Dr. Robert Koch of Berlin, who has
merely confirmed the observations of the earlier workers.--E. R. L.
FOOTNOTES:
[1] The foundation of the Royal Society of London is most intimately
connected with the University of Oxford. Dr. Wallis, an original
member, writes:--‘I take its first ground and foundation to have
been in London about the year 1645, when Dr. Wilkins and others met
weekly at a certain day and hour.... About the year 1648-9 some of
our company were removed to Oxford; first Dr. Wilkins, then I, and
soon after Dr. Goddard. Those in London continued to meet there as
before (and we with them, when we had occasion to be there), and
those of us at Oxford; with Dr. Ward (since Bishop of Salisbury),
Dr. Ralph Bathurst (now President of Trinity College in Oxford),
Dr. Petty (since Sir William Petty), Dr. Willis (then an eminent
physician in Oxford), and divers others, continued such meetings in
Oxford and brought those studies into fashion there; meetings first
at Dr. Petty’s lodgings (in an apothecarie’s house) because of the
convenience of inspecting drugs and the like, as there was occasion;
and after his remove to Ireland (though not so constantly) at the
lodgings of Dr. Wilkins, then Warden of Wadham College, and after
his removal to Trinity College in Cambridge, at the lodgings of
the Honourable Mr. Robert Boyle, then resident for divers years in
Oxford.... In the meanwhile our company at Gresham College being much
again increased by the accession of divers eminent and noble persons,
upon his Majesty’s return, we were (about the beginning of the year
1662) by his Majesty’s grace and favour incorporated by the name of
the Royal Society.’
[2] See, however, the letter from the _Times_, reprinted on p. 62.
[3] There is a tendency among writers on Variation, as affording
the opportunity for the operation of Natural Selection, to assume
that the variations presented by organisms are minute variations in
every direction around a central point. Those observers who have done
useful work in showing the definite and limited character of organic
variations have very generally assumed that they are opposing a
commonly held opinion that variation is of this equally distributed
character. I cannot find that Mr. Darwin made any such assumption;
and it is certain, and must on reflection have been recognized by all
naturalists, that the variations by the selection and intensification
of which natural selection has produced distinct forms or species,
and in the course of time altogether new groups of plants and
animals, are strictly limited to definite lines rendered possible,
and alone possible, by the constitution of the living matter of the
parental organism. We have no reason to suppose that the offspring
of a beetle could in the course of any number of generations present
variations on which selection could operate so as to eventually
produce a mammalian vertebrate; or that, in fact, the general result
of the process of selection of favourable variations in the past
has not been _ab initio_ limited by the definite and restricted
possibilities characteristic of the living substance of the parental
organisms of each divergent line or branch of the pedigree.
[4] See p. 62.
[5] M. Paul Bourget of the Académie Française, is not only a charming
writer of modern ‘novels,’ but claims to be a ‘psychologist,’ a title
which perhaps may be conceded to every author who writes of human
character. His works are so deservedly esteemed, and his erudition
is as a rule, so unassailable, that in selecting him as an example
of the frequent misrepresentation, among literary men, of Darwin’s
doctrine, I trust that my choice may be regarded as a testimony of
my admiration for his art. In his novel _Un Divorce_, published in
1904, M. Bourget, says: ‘La lutte entre les espèces, cette inflexible
loi de l’univers animal, a sa correspondance exacte dans le monde
des idées. Certaines mentalités constituent de véritables espèces
intellectuelles qui ne peuvent pas durer à côté les unes des autres’
(Edition Plon, p. 317). This inflexible law of the animal universe,
the struggle between species, is one which is quite unknown to
zoologists. The ‘struggle for existence,’ to which Darwin assigned
importance, is not a struggle between different species, but one
between closely similar _members of the same species_. The struggle
between species is by no means universal, but in fact very rare. The
preying of one species on another is a moderated affair of balance
and adjustment which may be described rather as an accommodation than
as a struggle.
A more objectionable misinterpretation of the naturalists’ doctrine
of the survival of the fittest in the struggle for existence is that
made by journalists and literary politicians, who declare, according
to their political bias, either that science rightly teaches that
the gross quality measured by wealth and strength alone can survive
and should therefore alone be cultivated, or that science (and
especially Darwinism) has done serious injury to the progress of
mankind by authorizing this teaching. Both are wrong, and owe their
error to self-satisfied flippancy and traditional ignorance in
regard to nature-knowledge and the teaching of Darwin. The ‘fittest’
does not mean the ‘strongest.’ The causes of survival under Natural
Selection are very far indeed from being rightly described as mere
strength, nor are they baldly similar to the power of accumulating
wealth. Frequently in Nature the more obscure and feeble survive
in the struggle because of their modesty and suitability to given
conditions, whilst the rich are sent empty away and the mighty perish
by hunger.
[6] A short discussion of this subject and the introduction of the
term ‘educability’ was published in a paper by me entitled ‘The
Significance of the Increased Size of the Cerebrum in recent as
compared with extinct Mammalia,’ Cinquantenaire de la Société de
Biologie, Paris, 1899, pp. 48-51.
It has been pointed out to me by my friend Dr. Andrews, of the
Geological Department of the British Museum, that the brain cavity
of the elephants was already of relatively large size in the Eocene
members of that group, which may be connected with the persistence of
these animals through subsequent geological periods.
[7] It would be an error to maintain that the process of Natural
Selection is entirely in abeyance in regard to Man. In an interesting
book, _The Present Evolution of Man_, Dr. Archdall Reid has shown
that in regard to zymotic diseases, and also in regard to the use of
dangerous drugs such as alcohol and opium, there is first of all the
acquirement of immunity by powerful races of men through the survival
among them of those strains tolerant of the disease or of the drug,
and secondly, the introduction of those diseases and drugs by the
powerful immune race, in its migrations, to races not previously
exposed either to the diseases or the drugs, and a consequent
destruction of the invaded race. The survival of the fittest is, in
these cases, a survival of the tolerant and eventually of the immune.
[8] ‘Religion means the knowledge of our destiny and of the means
of fulfilling it.’--_Life and Letters of Mandell Creighton sometime
Bishop of London_, vol. ii. p. 195.
[9] This has been established in the case of the _Trypanosoma
Brucei_, a minute parasite living in the blood of big game
in south-east Africa, amongst which it is disseminated by a
blood-sucking fly, the _Glossina morsitans_ or Tsetze fly. The
parasite appears to do little or no harm to the native big game, but
causes a deadly disease both in the horses and cattle introduced by
Europeans and in the more anciently introduced native cattle (of
Indian origin). Similar cases are found where a disease germ (such
as that of measles) produces but a small degree of sickness and
mortality in a population long associated with it, but is deadly to
a human community to which it is a new-comer. Thus Europeans have
introduced measles with deadly results in the South Sea Islands. A
similar kind of difficulty, of which many might be cited, is brought
about by man’s importations and exportations of useful plants. He
thus brought the Phylloxera to Europe, not realizing before hand
that this little parasitic bug, though harmless to the American
vine, which puts out new shoots on its roots when the insect injures
the old ones, is absolutely deadly to the European vine, which
has not acquired the simple but all-important mode of growth by
which the American vine is rendered safe. Thus, too, he took the
coffee-plant to Ceylon, and found his plantations suddenly devastated
by a minute mould, the _Himileia vastatrix_, which had lived very
innocently before that in the Cingalese forests, but was ready to
burst into rapacious and destructive activity when the new unadjusted
coffee-trees were imported by man and presented in carefully crowded
plantations to its unrestrained infection.
[10] The phosphorescent disease of the sand-hopper (_Talitrus_) is
described by Giard and Billet in a paper entitled ‘Observations
sur la maladie phosphorescente des Talitres et autres Crustacés,’
in the memoirs of the Société de Biologie, Oct. 19, 1889. Billet
subsequently gave a further account of this organism, and named
it _Bacillus Giardi_--after Professor Giard of Paris. (Bulletins
scientifiques de la France et de la Belgique, xxi. 1898, p. 144).
It appears that the parasite is transmitted from one individual to
another in coition. The specimens studied by Giard and Billet were
obtained at Wimereux near Boulogne. I found the disease very abundant
at Ouistreham near Caen in the summer of 1900. I have not observed
it nor heard of its occurrence on the English coast. Sea-water
commonly contains a free-living phosphorescent bacterium which can
be cultivated in flasks of liquid food so as to give rich growths
which glow like a lamp when the flask is agitated so as to expose the
contents to oxidation. This bacterium is not, however, the cause of
the ‘phosphorescence’ of the sea often seen on our coasts. That is
due in most cases to a much larger organism, as big as a small pin’s
head, and known as _Noctiluca miliaris_.
[11] As little is the question of the use and abuse of food and drink
dealt with, as yet, by civilized man. As in many other matters man
has carried into his later crowded, artificial, nature-controlling
life habits and tendencies derived from savage prehistoric days, so
has he perpetuated ways of feeding which are mere traditions from his
early ‘animal’ days, and have never been seriously called in question
and put to proof. The persistence under new conditions of either
habit or structure which belonged to old conditions may be attended
with great danger and difficulty to an organism which changes, as
man does, with great rapidity important features in its general
surroundings and mode of life. This is in effect Metschnikoff’s
doctrine of ‘désharmonies.’ It is probable that in very early days
when a tribe of primitive men killed a mammoth, they all rushed on
to the dead monster and gorged as much of its flesh as they could
swallow (cooked or possibly uncooked). They had to take in enough to
last for another week or two--that is to say, until another large
animal should be trapped and slain. Accordingly he who could eat most
would be strongest and best able to seize a good share when the next
opportunity arrived, and it naturally became considered an indication
of strength, vigour, and future prosperity to be capable of gorging
large quantities of food. By means of the phrases ‘enjoying a good
appetite,’ or ‘a good trencherman,’ or other such approving terms,
civilized society still encourages the heavy feeder. The lower
classes always consider a ravenous appetite to be an indication of
strength and future prosperity in a child. Most healthy men, and
even many women, in Western Europe, attack their food and swallow
it without sufficient mastication, and as though they did not hope
to get another chance of feeding for a week or two to come. Medical
men have never ventured to investigate seriously whether civilized
man is doing best for his health in behaving like a savage about
his food. It is their business to attend to the patient with a
disordered digestion, but not to experiment upon the amount of food
of various kinds which the modern man should swallow in order to
avoid indigestion and yet supply his alimentary needs. No individual
can possibly pay medical men to make these observations. It is the
business of the State to do so, because such knowledge is not only
needed by the private citizen, but is of enormous importance in the
management of armies and navies, in the victualling of hospitals,
asylums, and prisons. Thousands of tons of preserved meat have been
wasted in recent wars because the reckless and ignorant persons who
purchased the preserved meat to feed soldiers had never taken the
trouble to ascertain whether preserved meat can be eaten by a body of
men as a regular and chief article of diet. It appears that certain
methods of preserving meat render it innutritious and impossible as
a diet.
It is probable from recent experiment that we all, except those
unfortunate few who do not get enough, eat about twice as much
as we require, and that the superfluous quantity swallowed not
only is wasted, but is actually a cause of serious illness and
suffering. It surely is an urgent matter that these questions about
food should be thoroughly investigated and settled. In the opinion
of the most eminent physiologist of the United States (Professor
Bowditch), we shall never establish a rational and healthy mode of
feeding ourselves until we give up the barbarous but to some persons
pleasant custom of converting the meal into a social function; we
are thus tempted into excess. Only long and extensive experiment
can provide us with definite and conclusive information on this
matter, which is far more important than, at first sight, it seems
to be. And similarly with regard to the admittedly serious question
of alcohol--only very extensive and authoritative experiment will
suffice to show mankind whether it is a wise and healthy thing to
take it in small quantities, the exact limits of which must be
stated, or to reject it altogether.
[12] It is, perhaps, needful to point out that what is aimed at is
that the education of all the youth of the country, both of pass-men
and of class-men, of girls as well as of boys, of the rich as
well as of the poor, should be primarily directed to imparting an
acquaintance with what we already possess in respect of knowledge
of Nature, and the training of the pupil so as to enable him or
her (_a_) to make use of that knowledge, and (_b_) to take part
in gaining new knowledge of Nature, at this moment needed but
non-existent. This does not involve the complete exclusion of other
subjects of instruction, to which about one-third of the time and
effort of school and college life might be devoted.
[13] I desire especially to draw the attention of those who have
misunderstood and misrepresented my estimate of the importance of the
study of History, to this paragraph.--E.R.L.
[14] The practical steps which would correspond to the views
enunciated in this discourse are two. First, the formation of an
educational association to establish one or more schools and colleges
in which nature-knowledge and training in nature-searching should
be the chief matters to which attention would be given, whilst
reasonable methods would also be employed for implanting in the
minds of the students a love and understanding of literature and
other forms or art. Those who desired such an education for their
children would support these schools and colleges, just as in the
days of Anglican exclusiveness the Nonconformists and Roman Catholics
supported independent educational institutions. The second practical
step would be the formation of a political union which would make due
respect to efficiency, that is to say, to a knowledge of Nature, a
test question in all political contests. No candidate for Parliament
would receive the votes of the union unless he were either himself
educated in a knowledge of Nature or promised his support exclusively
to ministers who would insist on the utilization of nature-knowledge
in the administration of the great departments of State, and would
take active measures of a financial character to develop with far
greater rapidity and certainty than is at present the case, that
inquiry into and control of Nature which is the indispensable factor
in human welfare and progress. Such a programme will, I hope,
at no distant date obtain the support of a sufficient number of
parliamentary voters to raise political questions of a more genuine
and interesting character than those which many find so tedious at
the present moment.
[15] It seems necessary to emphasize that I here say merely that
no “new support” is given to the notion of so-called telepathy, a
support some persons have wrongly claimed. I do not say that the
notion is rendered less likely to prove true than it was before.
[16] See the introduction to Part II. of a Treatise on Zoology.
Edited by E. Ray Lankester (London: A. & C. Black).
[17] From the Jubilee volume of the Soc. de Biol. of Paris, 1899.
Reprinted in _Nature_, vol. lxi., 1900, pp. 624, 625.
[18] I use the term ‘acquired’ without prejudice in the sense given
to that word by Lamarck himself. It is of primary importance that
those who follow this controversy should clearly understand what
Lamarck pointed to by this word ‘acquired.’ Utter confusion and
absurdity has resulted from a misunderstanding on this subject
by some writers who deliberately call newly appearing congenital
characters ‘acquired’ or ‘acquisitions.’
[19] _Nature_, vol. li., 1894, p. 127.
[20] In a review of Metschnikoff’s ‘Leçons sur l’Inflammation’ in
_Nature_, 1899.
[21] See the next chapter, devoted to this subject.
[22] I had the honour and good fortune to found this association and
to collect the funds so generously given to it--then for many years
to act as its honorary secretary, to design and superintend the
erection of the laboratory and to organize, in conjunction with my
scientific colleagues, its staff, its scheme of work and government.
On the death of our beloved president, Professor Huxley, I was
elected as his successor, and still occupy that position.
[23] The disease has actually entered into the administrative area
known as British East Africa, but has not made any rapid progress
towards the coast. According to a report by Dr. Wiggins, the disease
is confined in British East Africa, as in Uganda, to those areas in
which _Glossina palpalis_ occurs.
[24] Only last year (1905) Lieut. Tulloch, of the Army Medical
Department, who with Professor Minchin was engaged in carrying on
further researches for the Royal Society on the sleeping sickness
at Entebbe in Uganda, became infected by the trypanosome, probably
through an unobserved bite by a tsetze fly, and died of the disease
soon after his return to England.
[25] Professor Minchin investigated this subject during 1905 in
Uganda whither he went on behalf of the Tropical Diseases Committee
of the Royal Society. He did not discover anything corresponding
to the development of the malarial parasite in the gnat, but his
investigations are not yet brought to a conclusion (December, 1906).
[26] Dr. Schaudinn died in 1906. He was only 35 years of age.
[27] Since this was written a professorship of Protozoology has
with the assistance of the Colonial Office been established in the
University of London. This is a first step towards a recognition of
the duty of the State in this matter.
[28] See footnote on p. 179.
* * * * * *
Transcriber’s note:
The repeated caption heading ‘Fig. x.’ has been removed in Figures
1, 2, 3, 4, 10, 12 and 44.
Obvious typographical errors and punctuation errors have been
corrected after careful comparison with other occurrences within
the text and consultation of external sources.
Except for those changes noted below, all misspellings in the text,
and inconsistent or archaic usage, have been retained: for example,
sleeping sickness, sleeping-sickness; kosmos; acquirement; employés;
imbibition.
Pg 84 (Fig. 11): ‘at 3186 (Soddy)’ replaced by ‘at 318·6 (Soddy)’.
Pg 91 (Fig. 12): ‘the line A A)’ replaced by ‘the line A A,’.
Pg 95: ‘Brunettière and his’ replaced by ‘Brunetière and his’.
Pg 146 (Fig. 46): ‘T. Brucii’ replaced by ‘T. Brucei’.
Pg 148: ‘Spirocheta pallida’ replaced by ‘Spirochæta pallida’.
Pg 149: ‘of the commuity,’ replaced by ‘of the community,’.
Pg 177: ‘miscroscopic animals’ replaced by ‘microscopic animals’.
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