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Title: Food Poisoning
Author: Jordan, Edwin Oakes
Language: English
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  THE UNIVERSITY OF CHICAGO
  SCIENCE SERIES



 _Editorial Committee_

  ELIAKIM HASTINGS MOORE, _Chairman_
  JOHN MERLE COULTER
  ROBERT ANDREWS MILLIKAN


The University of Chicago Science Series, established by the Trustees of
the University, owes its origin to a feeling that there should be a
medium of publication occupying a position between the technical
journals with their short articles and the elaborate treatises which
attempt to cover several or all aspects of a wide field. The volumes of
the series will differ from the discussions generally appearing in
technical journals in that they will present the complete results of an
experiment or series of investigations which previously have appeared
only in scattered articles, if published at all. On the other hand, they
will differ from detailed treatises by confining themselves to specific
problems of current interest, and in presenting the subject in as
summary a manner and with as little technical detail as is consistent
with sound method.



FOOD POISONING


  THE UNIVERSITY OF CHICAGO PRESS
  CHICAGO, ILLINOIS


+Agents+

  THE BAKER & TAYLOR COMPANY
  NEW YORK

  THE CUNNINGHAM, CURTISS & WELCH COMPANY
  LOS ANGELES

  THE CAMBRIDGE UNIVERSITY PRESS
  LONDON AND EDINBURGH

  THE MARUZEN-KABUSHIKI-KAISHA
  TOKYO, OSAKA, KYOTO, FUKUOSA, SENDAI

  THE MISSION BOOK COMPANY
  SHANGHAI



FOOD POISONING

  _By_

EDWIN OAKES JORDAN

  _Chairman of the Department of Hygiene and Bacteriology
  The University of Chicago_

[Illustration: emblem]

  THE UNIVERSITY OF CHICAGO PRESS
  CHICAGO, ILLINOIS



  COPYRIGHT 1917 BY
  THE UNIVERSITY OF CHICAGO

  All Rights Reserved

  Published May 1917



  Composed and Printed By
  The University of Chicago Press
  Chicago, Illinois, U.S.A.



CONTENTS


  CHAPTER                                               PAGE

  I. INTRODUCTION                                          1
    The Extent of Food Poisoning
    Various Kinds of Food Poisoning
    The Articles of Food Most Commonly
      Connected with Food Poisoning

  II. SENSITIZATION TO PROTEIN FOODS                       9

  III. POISONOUS PLANTS AND ANIMALS                       13
    Poisonous Plants
    Poisonous Animals

  IV. MINERAL OR ORGANIC POISONS ADDED TO FOOD            26
    Arsenic
    Antimony
    Lead
    Tin
    Copper
    Various Coloring Substances
    Food Preservatives
    Food Substitutes

  V. FOOD-BORNE PATHOGENIC BACTERIA                       44
    Typhoid Food Infection
    Asiatic Cholera
    Tuberculosis
    Various Milk-borne Infections
    Possible Infection with _B. proteus_

  VI. FOOD-BORNE PATHOGENIC BACTERIA (_Continued_)        58
    Paratyphoid Infection
      Typical Paratyphoid Outbreaks
      General Characters of Paratyphoid Infection
      Toxin Production
      Sources of Infection
      Means of Prevention

  VII. ANIMAL PARASITES                                   79
    Trichiniasis
    Teniasis
    Uncinariasis
    Other Parasites

  VIII. POISONOUS PRODUCTS FORMED IN FOOD BY BACTERIA
    AND OTHER MICRO-ORGANISMS                             85
    Ergotism
    Botulism
      Symptoms
      Anatomical Lesions
      Bacteriology
      Epidemiology
      Prevention and Treatment
    Other Bacterial Poisons
    Spoiled and Decomposed Food

  IX. POISONING OF OBSCURE OR UNKNOWN NATURE             100
    Milksickness or Trembles
    Deficiency Diseases
      Beriberi
      Pellagra
      Lathyrism
      Favism
      Scurvy
      Rachitis
    The Foods Most Commonly Poisonous

  INDEX                                                  109



CHAPTER I

INTRODUCTION


How frequently food poisoning occurs is not definitely known. Everybody
is aware that certain articles of food are now and again held
responsible for more or less severe "attacks of indigestion" or other
physiological disturbances that have followed their consumption, but in
many cases the evidence for assuming a causal connection is of the
slightest. That convenient refuge from etiological uncertainty, "ptomain
poisoning," is a diagnosis that unquestionably has been made to cover a
great variety of diverse conditions, from appendicitis and the pain
caused by gallstones to the simple abdominal distention resulting from
reckless gorging.

No doubt can be entertained, however, that intestinal and other
disorders due to particular articles of food occur much more frequently
than they are recorded. There are few persons who have not experienced
gastro-intestinal attacks of moderate severity which could be reasonably
attributed to something eaten shortly before. It is often possible to
specify with a fair degree of certainty the offending food. The great
majority of such attacks are of a mild character, are quickly recovered
from, and are never heard of beyond the immediate family circle. Only
when the attack is more serious than the average or when a large number
of persons are affected simultaneously does knowledge of the occurrence
become more widely spread. A small proportion of food-poisoning cases
receives notice in the public press and a still smaller proportion is
reported in the medical journals. Very few indeed are ever completely
investigated as to their origin.

Although most attacks of food poisoning are usually of a slight and
apparently temporary nature, it does not follow that they are to be
considered negligible or of trivial importance from the standpoint of
public health. The human organism is always more or less weakened by
such attacks, many of them, as we shall see, genuine infections; and, as
is known to be the case with many infectious diseases, some permanent
injurious impression may be left on the body of the affected individual.
Under certain conditions it is possible that degenerative changes are
initiated or accelerated in the kidneys or blood vessels by the acute
poisoning which is manifested for a short time in even the milder cases.
In yet greater degree these changes may follow those insidious forms of
food poisoning due to the frequent ingestion of small quantities of
mineral or organic poisons, which in each dose may cause little or no
measurable physiological change, but whose cumulative effect may be
vicious. In view of the grave situation evidenced by the increase in the
degenerative diseases affecting early middle life in the United
States,[1] the extent, causes, and means of prevention of food poisoning
seem pressing subjects for investigation.


THE EXTENT OF FOOD POISONING

Since cases of food poisoning, "ptomain poisoning," and the like are not
required by law to be reported, public health authorities in general
possess no information respecting their occurrence. Very indirect and
imperfect indications of the prevalence of certain kinds of food
poisoning are afforded by casual press reports. Such as they are, these
accounts are the only available material. Tables I and II summarize data
I have gathered through a press-clipping bureau and other sources during
the period October, 1913, to October, 1915. They serve to show at least
the universality and complexity of the problem.

The 375 group and family outbreaks together involved 5,238 persons.
While it is not probable that all the instances reported as due to food
poisoning can properly be so considered, there is no doubt that the
number recorded in the tables falls far short of the actual occurrences.
In the past few years the writer has investigated several large
food-poisoning outbreaks which have never been reported in the press nor
received public notice in any way. There is reason to think that the
majority of cases escape notice. Probably several thousand outbreaks of
food poisoning in families and larger groups, affecting at least
15,000-20,000 persons, occur in the United States in the course of a
year.

The assignment of causes indicated in Table I is of limited value. The
tendency to incriminate canned food is here manifest. Proper
investigation of the origin of an outbreak is so rarely carried out that
the articles of food ordinarily accused are selected rather as the
result of popular prejudice and tradition than of any careful inquiry.

TABLE I

FOOD POISONING IN THE UNITED STATES, OCTOBER, 1913, TO OCTOBER, 1915

  =================================================================
          Assigned cause             |  Group   |          |
                                     |and Family|Individual|
                                     | Outbreaks|  Cases   |  Total
  -----------------------------------+----------+----------+-------
  Meat                               |    40    |    35    |    75
  Canned fish                        |    29    |    35    |    64
  Canned vegetables                  |    27    |    34    |    61
  Ice cream                          |    31    |    22    |    53
  Fish, oysters                      |    17    |    31    |    48
  Cheese                             |    31    |     9    |    40
  Sausage and canned meat            |    18    |    18    |    36
  Milk                               |    14    |    13    |    27
  Mushrooms                          |    12    |     7    |    19
  Fruit                              |     8    |    11    |    19
  Vegetables                         |    11    |     7    |    18
  Fowl                               |    12    |     4    |    16
  Salad                              |     9    |     5    |    14
  Contact of food or drink with metal|    12    |     1    |    13
  Miscellaneous                      |    29    |    55    |    84
  -----------------------------------+----------+----------+-------
                                     |   300    |   287    |   587
  No cause assigned                  |   357    |    88    |   445
  -----------------------------------+----------+----------+-------
                                     |   657    |   375    | 1,032
  -----------------------------------------------------------------

TABLE II

SEASONAL DISTRIBUTION OF FOOD POISONING CASES, 1914-15 (GROUP, FAMILY,
AND INDIVIDUAL)

  ==========================================
  January | 90 ||May   | 63 ||September| 76
  February| 66 ||June  |108 ||October  | 96
  March   | 75 ||July  | 99 ||November | 96
  April   | 79 ||August| 96 ||December | 88
  ------------------------------------------

There is no very striking seasonal incidence apparent in the figures
here gathered (Table II). The warmer months seem to have a slight
preponderance of cases, but general conclusions from such data are
hardly warranted.


VARIOUS KINDS OF FOOD POISONING

Cases of poisoning by articles of food may be distinguished as: (1)
those caused by some injurious constituent in the food itself, and (2)
those caused by a peculiar condition of the individual consuming the
food, by virtue of which essentially wholesome food substances are
capable of producing physiological disturbance in certain individuals.
The latter group includes persons, apparently normal in other respects,
who are more or less injuriously affected by some particular article of
diet, such as eggs or milk, which is eaten with impunity by all normal
individuals. This is the so-called food sensitization or food allergy.

Food poisoning, as more commonly understood, is due to the composition,
contents, or contamination of the food itself. It is not within the
scope of this book to consider any of those cases in which definite
poisonous substances are added to food with criminal intent. The term
food poisoning is here taken to include the occasional cases of
poisoning from organic poisons present in normal animal or plant
tissues, the more or less injurious consequences following the
consumption of food into which formed mineral or organic poisons have
been introduced by accident or with intent to improve appearances or
keeping quality, the cases of infection due to the swallowing of
bacteria and other parasites which infest or contaminate certain foods,
and the poisoning due to deleterious substances produced in food by the
growth of bacteria, molds, and similar organisms. As already pointed
out, little is known about the relative frequency of occurrence of these
different causes or the extent to which they are separately and
collectively operative.


THE ARTICLES OF FOOD MOST COMMONLY CONNECTED WITH FOOD POISONING

In addition to the definitely poisonous plants or animals, certain
everyday articles of food have been frequently associated with the more
serious outbreaks of food poisoning. Meat in particular has been
implicated so often that the term meat poisoning is used about as
commonly as the term food poisoning in general discussions of this
subject. Certain it is that the great majority of the best-studied and
most severe outbreaks of food poisoning have been attributed on good
grounds to the use of meat or meat products. Other animal foods, and
especially milk and its derivatives, cheese and ice-cream, have likewise
been held responsible for extensive and notable outbreaks.

Perhaps the most significant feature of food poisoning attacks is the
frequency with which they have been traced to the use of raw or
imperfectly cooked food. The probable interpretation of this fact will
be discussed in the later chapters. Especially have the use of uncooked
milk, either by itself or mixed with other food substances, and the
eating of raw sausage brought in their train symptoms of poisoning in a
disproportionately large number of cases.

Canned goods of various sorts have likewise been repeatedly accused of
causing injurious effects, but the evidence adduced is not always
convincing. The actual degree of danger from this source is far from
being determined. The National Canners Association publishes in the
annual report of the secretary a brief list of "libels on the industry"
or instances in which canned foods of various sorts were regarded as the
cause of illness. The 1916 report contains fifty-one cases of this
character, none of which was considered by the investigator of the
Association to be based on sound evidence. A still more searching
investigation of all such cases would seem to be desirable, not with a
view to incriminating or exculpating any particular product, but simply
for the purpose of ascertaining and placing on record all the facts.


FOOTNOTES:

[1] Tables A and B show that the "expectation of life" for adults of
forty years and over is shorter in New York City now than it was thirty
years ago (Table A), and that this increase in the death-rate in the
higher-age groups is manifested in recent years in a wide area in this
country (Table B). This increased mortality is due chiefly to diseases
of the heart, arteries, and kidneys, and to cancer.

TABLE A[1a]

APPROXIMATE LIFE TABLE, TRIENNA 1879-81 AND 1909-11, BASED ON NEW YORK
CITY STATISTICS

  ==================================================
          |Expectation|Expectation|   Gain (+) or
          |  of Life, |  of Life, |Loss (-) in Years
     Ages |  1879-81  |  1909-11  |  of Expectancy
  --------+-----------+-----------+-----------------
  Under 5 |   41.3    |   51.9    |      +10.6
        5 |   46.3    |   51.1    |      + 4.8
       10 |   43.8    |   46.9    |      + 3.1
       15 |   39.7    |   42.5    |      + 2.8
       20 |   35.8    |   38.3    |      + 2.5
       25 |   32.6    |   34.3    |      + 1.7
       30 |   29.6    |   30.5    |      + 0.9
       35 |   26.7    |   26.9    |      + 0.2
       40 |   23.0    |   23.4    |      - 0.5
       45 |   21.1    |   20.0    |      - 1.1
       50 |   18.3    |   16.8    |      - 1.5
       55 |   15.4    |   13.9    |      - 1.5
       60 |   13.0    |   11.3    |      - 1.7
       65 |   10.5    |    9.1    |      - 1.4
       70 |    8.9    |    7.2    |      - 1.7
       75 |    7.3    |    5.5    |      - 1.8
       80 |    6.4    |    4.3    |      - 2.1
       85 |    5.5    |    2.2    |      - 3.3
  Balance |           |           |      +26.6
          |           |           |      -16.6
          |           |           |-----------------
          |           |           |      +10.0
  --------------------------------------------------

TABLE B[1b]

COMPARISON OF MORTALITY OF MALES AND FEMALES, BY AGE GROUPS. DEATH-RATES
PER 1,000 POPULATION (REGISTRATION STATES AS CONSTITUTED IN 1900)

  ============================================================
  Ages        |   Males   |Percentage |  Females  |Percentage
              |-----------|Increase or|-----------|Increase or
              | 1900| 1911| Decrease  | 1900| 1911| Decrease
  ------------+-----+-----+-----------+-----------------------
  Under 5     | 54.2| 39.8|   -26.27  | 45.8| 33.3|   -27.29
      5-9     |  4.7|  3.4|   -27.66  |  4.6|  3.1|   -32.61
    10-14     |  2.9|  2.4|   -17.24  |  3.1|  2.1|   -32.26
    15-19     |  4.9|  3.7|   -24.49  |  4.8|  3.3|   -31.25
    20-24     |  7.0|  5.3|   -24.29  |  6.7|  4.7|   -29.85
    25-34     |  8.3|  6.7|   -19.28  |  8.2|  6.0|   -26.83
    35-44     | 10.8| 10.4|    -3.70  |  9.8|  8.3|   -15.31
    45-54     | 15.8| 16.1|    +1.90  | 14.2| 12.9|    -9.15
    55-64     | 28.9| 30.9|    +6.92  | 25.8| 26.8|    +0.78
    65-74     | 59.6| 61.6|    +3.36  | 53.8| 55.1|    +2.42
   75 and over|146.1|147.4|    +0.89  |139.5|139.2|    +0.22
   All ages   | 17.6| 15.8|   -10.23  | 16.5| 14.0|   -15.15
  ------------------------------------------------------------

[1a] _Monthly Bull., Dept. of Health, City of New York_, III (1913),
113.

[1b] Dublin, _Amer. Jour. Public Health_, III (1915), 1262.



CHAPTER II

SENSITIZATION TO PROTEIN FOODS


The first introduction under the skin of a guinea-pig of a minute
quantity of egg-white or other apparently harmless protein substance is
itself without visible injurious effect, but if this is followed by a
second injection of the same substance after an interval of about ten
days, the animal will die in a few minutes with symptoms of violent
poisoning. Whatever be the physiological explanation of the remarkable
change that thus results from the incorporation of foreign protein into
the body, there can be no doubt that the phenomenon known as protein
sensitization or anaphylaxis is relatively common.[2] Sensitization to
proteins came to light in the first instance through the study of
therapeutic sera, and has been found to have unexpectedly wide bearings.
It is now known that not only the rash and other symptoms which
sometimes follow the administration of horse serum containing diphtheria
antitoxin, but the reaction to tuberculin and similar accompaniments of
bacterial infection, are probably to be explained on the principle of
anaphylactic change. The sensitiveness of certain individuals to the
pollen of particular plants (hay fever) is also regarded as a typical
instance of anaphylaxis, accompanied as it is by asthma and other
characteristic manifestations of the anaphylactic condition.

Among the reactions usually classed as anaphylactic are the occasional
cases of sensitivity to particular food substances. It is a familiar
fact that certain foods that can be eaten with impunity by most persons
prove more or less acutely poisonous for others. Strawberries and some
other fruits and some kinds of shellfish are among the articles of food
more commonly implicated. Unpleasant reactions to the use of eggs and of
cow's milk are also noted. The severity of the attacks may vary from a
slight rash to violent gastro-intestinal, circulatory, and nervous
disturbances.

Coues[3] has described a rather typical case in a child twenty-one
months old and apparently healthy except for some eczema. When the child
was slightly over a year old egg-white was given to it, and nausea and
vomiting immediately followed. About eight months later another feeding
with egg-white was followed by sneezing and all the symptoms of an acute
coryza. Extensive urticaria covering most of the body also appeared, and
the eyelids became edematous. The temperature remained normal and there
was no marked prostration. The symptoms of such attacks vary
considerably in different individuals, but usually include pronounced
urticaria along with nausea, vomiting, and diarrhea. The rapidity with
which the symptoms appear after eating is highly characteristic.
Schloss[4] has reported a case of an eight-year-old boy who evinced
marked sensitiveness to eggs, almonds, and oatmeal. Experiments in this
instance showed that a reaction was produced only by the proteins of
these several foods, and that extracts and preparations free from
protein were entirely inert. It was further found that by injection of
the patient's blood serum guinea-pigs could be passively sensitized
against the substances in question, thus showing the condition to be one
of real anaphylaxis.

Idiosyncrasy to cow's milk which is observed sometimes in infants is an
anaphylactic phenomenon.[5] The substitution of goat's milk for cow's
milk has been followed by favorable results in such cases.

In very troublesome cases of protein idiosyncrasy a method of treatment
based on animal experimentation has been advocated. This consists in the
production of a condition of "anti-anaphylaxis" by systematic feeding of
minute doses of the specific protein substance concerned.[6] S. R.
Miller[7] describes the case of a child in whom a constitutional
reaction followed the administration of one teaspoonful of a mixture
composed of one pint of water plus one drop of egg-white, while a like
amount of albumen diluted with one quart of water was tolerated
perfectly. "Commencing with the dilution which failed to produce a
reaction, the child was given gradually increasing amounts of solutions
of increasing strength. The dosage was always one teaspoonful given
three times during the day; the result has been that, in a period of
about three months, the child has been desensitized to such an extent
that one dram of pure egg-white is now taken with impunity."

Many other instances of anaphylaxis to egg albumen are on record.[8] In
some of these cases the amount of the specific protein that suffices to
produce the reaction is exceedingly small. One physician writes of a
patient who "was unable to take the smallest amount of egg in any form.
If a spoon was used to beat eggs and then to stir his coffee, he became
very much nauseated and vomited violently."[9]

The dependence of many cases of "asthma" upon particular foods is an
established fact. Various skin rashes and eruptions are likewise
associated with sensitization to certain foods.[10] McBride and
Schorer[11] consider that each particular kind of food (as tomatoes or
cereals) produces a constant and characteristic set of symptoms.
Possibly certain definitely characterized skin diseases are due to this
form of food poisoning. Blackfan[12] found that of forty-three patients
without eczema only one showed any evidence of susceptibility to protein
by cutaneous and intracutaneous tests, while of twenty-seven patients
with eczema twenty-two gave evidence of susceptibility to proteins.


FOOTNOTES:

[2] General agreement respecting the true physiological and chemical
nature of anaphylactic phenomena has not yet been reached. For a
discussion of the theories of anaphylaxis, see in Hans Zinsser,
_Infection and Resistance_ (New York, 1914), chaps. xv-xviii; also
Doerr, "Allergie und Anaphylaxis," in Kolle and Wassermann, _Handbuch_,
2d edition, 1913, II, 947.

[3] _Boston Med. and Surg. Jour._, CLXVII (1912), 216.

[4] _Amer. Jour. Obstet._ (New York), LXV (1912), 731.

[5] F. B. Talbot, _Boston Med. and Surg. Jour._, CLXXV (1916), 409.

[6] See, for example, Schloss, _loc. cit._

[7] _Johns Hopkins Hosp. Bull._, XXV (1914), 78.

[8] See, for example, K. Koessler, _Ill. Med. Jour._, XXIII (1913), 66;
Bronfenbrenner, Andrews, and Scott, _Jour. Amer. Med. Assoc._, LXIV
(1915), 1306; F. B. Talbot, _Boston Med. and Surg. Jour._, CLXXI (1914),
708.

[9] _Jour. Amer. Med. Assoc._, LXV (1915), 1837.

[10] Strickler and Goldberg, _Jour. Amer. Med. Assoc._, LXVI (1916),
249.

[11] _Jour. Cutaneous Dis._, XXXIV (1916), 70.

[12] _Amer. Jour. Dis. of Children_, XI (1916), 441.



CHAPTER III

POISONOUS PLANTS AND ANIMALS


Some normal plant and animal tissues contain substances poisonous to man
and are occasionally eaten by mistake for wholesome foods.


POISONOUS PLANTS

Poisonous plants have sometimes figured conspicuously in human affairs.
Every reader of ancient history knows how Socrates "drank the hemlock,"
and how crafty imperial murderers were likely to substitute poisonous
mushrooms for edible ones in the dishes prepared for guests who were out
of favor. In our own times the eating of poisonous plants is generally
an accident, and poisoning from this cause occurs chiefly among the
young and the ignorant.

According to Chesnut[13] there are 16,673 leaf-bearing plants included
in Heller's _Catalogue of North American Plants_, and of these nearly
five hundred, in one way or another, have been alleged to be poisonous.
Some of these are relatively rare or for other reasons are not likely to
be eaten by man or beast; others contain a poison only in some
particular part, or are poisonous only at certain seasons of the year;
in some the poison is not dangerous when taken by the mouth, but only
when brought in contact with the skin or injected beneath the skin or
into the circulation. There are great differences in individual
susceptibility to some of these plant poisons. One familiar plant, the
so-called poison-ivy, is not harmful for many people even when handled
recklessly; it can be eaten with impunity by most domestic animals.

The actual number of poisonous plants likely to be inadvertently eaten
by human beings is not large. Chesnut[14] has enumerated about thirty
important poisonous plants occurring in the United States, and some of
these are not known to be poisonous except for domestic animals.[15]
Many of the cases of reported poisoning in man belong to the class of
exceedingly rare accidents and are without much significance in the
present discussion. Such are the use of the leaves of the American false
hellebore (_Veratrum viride_) in mistake for those of the
marsh-marigold[16], the use of the fruit pulp of the Kentucky coffee
tree (_Gymnocladus dioica_) in mistake for that of the honey-locust[17],
the accidental employment of daffodil bulbs for food, and the confusion
by children of the young shoots of the broad-leaf laurel (_Kalmia
latifolia_) with the wintergreen.[18] One of the most serious
instances of poisoning of this sort is that from the use of the
spindle-shaped roots of the deadly water hemlock (_Cicuta maculata_)
allied to the more famous but no more deadly poison hemlock. These
underground portions of the plant are sometimes exposed to view by
washing out or freezing, and are mistaken by children for horseradish,
artichokes, parsnips, and other edible roots. Poisoning with water
hemlock undoubtedly occurs more frequently than shown by any record.
Eight cases and two deaths from this cause are known to have occurred in
one year in the state of New Jersey alone.

[Illustration: FIG. 1.--_Conium maculatum._ The fresh juice of _Conium
maculatum_ was used in the preparation of the famous hemlock potion
which was employed by the Greeks in putting their criminals to death.
(From _Applied and Economic Botany_, by courtesy of Professor Kraemer
[after Holm].)]

An instance of food poisoning to be included under this head is the
outbreak in Hamburg and some thirty other German cities in 1911 due to
the use of a poisonous vegetable fat in preparing a commercial butter
substitute.[19] In the attempt to cheapen as far as possible the
preparation of margarin various plant oils have been added by the
manufacturers. In the Hamburg outbreak, in which over two hundred cases
of illness occurred, poisoning was apparently due to substitution of
so-called maratti-oil, derived from a tropical plant (_Hydrocarpus_).
This fat is said to be identical with oil of cardamom, and its toxic
character in the amounts used in the margarin was proved by animal
experiment. Increasing economic pressure for cheap foods may lead to the
recurrence of such accidents unless proper precautions are used in
testing out new fats and other untried substances intended for use in
the preparation of food substances.[20]

[Illustration: FIG. 2.--_Cicuta maculata_ (water hemlock); _A_, upper
part of stem with leaves and compound umbels; _B_, base of stem and
thick tuberous roots; _C_, cross-section of stem; _D_, flower; _E_,
fruit; _F_, fruit in longitudinal section; _G_, cross-section of a
mericarp. (From _Applied and Economic Botany_, by courtesy of Professor
Kraemer [after Holm].)]

Investigators from the New York City Health Department have found that
certain cases of alleged "ptomain poisoning" were really due to
"sour-grass soup."[21] This soup is prepared from the leaves of a
species of sorrel rich in oxalic acid. In one restaurant it was found
that the soup contained as much as ten grains of oxalic acid per pint!

[Illustration: FIG. 3.--Fly Amanita (poisonous). (_Amanita muscaria_ L.)
(After Marshall, _The Mushroom Book_, by courtesy of Doubleday, Page &
Company.)]

By far the best-known example of that form of poisoning which results
from confounding poisonous with edible foods is that due to poisonous
mushrooms.[22] There is reason to believe that mushroom (or "toadstool")
intoxication in the United States has occurred with greater frequency of
late years, partly on account of the generally increasing use of
mushrooms as food and the consequently greater liability to mistake, and
partly on account of the growth of immigration from the mushroom-eating
communities of Southern Europe. Many instances have come to light in
which immigrants have mistaken poisonous varieties in this country for
edible ones with which they were familiar at home. In the vicinity of
New York City there were twenty-two deaths from mushroom poisoning in
one ten-day period (September, 1911) following heavy rains. The "fly
_Amanita_"[23] (_Amanita muscaria_) in this country has been apparently
often mistaken for the European variety of "royal _Amanita_" (_A.
caesaria_).[24] Such a mistake seems to have been the cause of death
of the Count de Vecchi in Washington, D.C., in 1897.

  The Count, an attaché of the Italian legation, a cultivated
  gentleman of nearly sixty years of age, considered something of an
  expert upon mycology, purchased, near one of the markets in
  Washington, a quantity of fungi recognized by him as an edible
  mushroom. The plants were collected in Virginia about seven miles
  from the city of Washington. The following Sunday morning the count
  and his physician, a warm personal friend, breakfasted together upon
  these mushrooms, commenting upon their agreeable and even delicious
  flavor. Breakfast was concluded at half after eight and within
  fifteen minutes the count felt symptoms of serious illness. So rapid
  was the onset that by nine o'clock he was found prostrate on his
  bed, oppressed by the sense of impending doom. He rapidly developed
  blindness, trismus, difficulty in swallowing, and shortly lost
  consciousness. Terrific convulsions then supervened, so violent in
  character as to break the bed upon which he was placed. Despite
  rigorous treatment and the administration of morphine and atropine,
  the count never recovered consciousness and died on the day
  following the accident. The count's physician on returning to his
  office was also attacked, dizziness and ocular symptoms warning him
  of the nature of the trouble. Energetic treatment with apomorphine
  and atropine was at once instituted by his colleagues and for a
  period of five hours he lay in a state of coma with occasional
  periods of lucidity. The grave symptoms were ameliorated and
  recovery set in somewhere near seven o'clock in the evening. His
  convalescence was uneventful, his restoration to health complete,
  and he is, I believe, still living. On this instance the count
  probably identified the fungi as _caesaria_ or _aurantiaca_.
  From the symptoms and termination the species eaten must have
  been _muscaria_.

_A. muscaria_ contains an alkaloidal substance which has a
characteristic effect upon the nerve centers and to which the name
muscarin and the provisional chemical formula C{5}H{15}NO{3} has been
given. The drug atropin is a more or less perfect physiological
antidote for muscarin and has been administered with success in cases of
muscarin poisoning. It is said that the peasants in the Caucasus are in
the habit of preparing from the fly _Amanita_ a beverage which they use
for producing orgies of intoxication. Deaths are stated to occur
frequently from excessive use of this beverage.[25]

The deadly _Amanita_ or death-cup (_A. phalloides_) is probably
responsible for the majority of cases of mushroom poisoning. Ford
estimates that from twelve to fifteen deaths occur annually in this
country from this species alone. This fungus is usually eaten through
sheer ignorance by persons who have gathered and eaten whatever they
chanced to find in the woods. A few of these poisonous mushrooms mixed
with edible varieties may be sufficient to cause the death of a family.
Ford thus describes the symptoms of poisoning with _A. phalloides_:

  Following the consumption of the fungi there is a period of six to
  fifteen hours during which no symptoms of poisoning are shown by the
  victims. This corresponds to the period of incubation of other
  intoxications or infections. The first sign of trouble is sudden
  pain of the greatest intensity localized in the abdomen, accompanied
  by vomiting, thirst, and choleraic diarrhoea with mucous and bloody
  stools. The latter symptom is by no means constant. The pain
  continues in paroxysms often so severe as to cause the peculiar
  Hippocratic facies, _la face vultueuse_ of the French, and though
  sometimes ameliorated in character, it usually recurs with greater
  severity. The patients rapidly lose strength and flesh, their
  complexion assuming a peculiar yellow tone. After three to four
  days in children and six to eight in adults the victims sink into a
  profound coma from which they cannot be roused and death soon ends
  the fearful and useless tragedy. Convulsions rarely if ever occur
  and when present indicate, I am inclined to believe, a mixed
  intoxication, specimens of _Amanita muscaria_ being eaten with the
  _phalloides_. The majority of individuals poisoned by the "deadly
  Amanita" die, the mortality varying from 60 to 100 per cent in
  various accidents, but recovery is not impossible when small amounts
  of the fungus are eaten, especially if the stomach be very promptly
  emptied, either naturally or artificially.

A number of other closely related species of _Amanita_ (e.g., _A.
verna_, the "destroying angel," probably a small form of _A.
phalloides_) have a poisonous action similar to that of _A. phalloides_.
All are different from muscarin.

[Illustration: FIG. 4.--Death-cup; destroying angel (_Amanita
phalloides_ Fries); reduced; natural size: cap, 3-1/2 inches; stem,
7-1/2 inches. (After Marshall, _The Mushroom Book_, by courtesy of
Doubleday, Page & Company.)]

The character of the poison was first carefully investigated by Kobert,
who showed that the _Amanita_ extract has the power of laking or
dissolving out the coloring matter from red blood corpuscles. This
hemolytic action is so powerful that it is exerted upon the red cells of
ox blood even in a dilution of 1:125,000. Ford[26] has since shown that
in addition to the hemolytic substance another substance much more toxic
is present in this species of _Amanita_ and he concludes that the
poisonous effect of the fungus is primarily due to the latter
("_Amanita_ toxin"). The juice of the cooked _Amanita_ is devoid of
hemolytic power, but is poisonous for animals in small doses, a fact
that agrees with the observation that these mushrooms, after cooking,
remain intensely poisonous for man. Extensive fatty degeneration in
liver, kidney, and heart muscle is produced by the true _Amanita_ toxin.
In the Baltimore cases studied by Clark, Marshall, and Rowntree[27]
the kidney rather than the liver was the seat of the most interesting
functional changes. These authors conclude that the nervous and mental
symptoms, instead of being due to some peculiar "neurotoxin," are
probably uremic in character. No successful method of treatment is
known. An antibody for the hemolysin has been produced, but an antitoxin
for the other poisonous substance seems to be formed in very small
amount. Attempts to immunize small animals with _Amanita_ toxin succeed
only to a limited degree.[28]


POISONOUS ANIMALS

While the muscles or internal organs of many animals are not palatable
on account of unpleasant flavor or toughness, there do not seem to be
many instances in which normal animal tissues are poisonous when eaten.
As pointed out elsewhere (chapter vi), the majority of outbreaks of meat
and fish poisoning must be attributed to the presence of pathogenic
bacteria or to poisons formed after the death of the animal. This has
been found especially true of many of the outbreaks of poisoning
ascribed to oysters and other shellfish; in most, if not all, cases the
inculpated mollusks have been derived from water polluted with human
wastes and are either infected or partially decomposed.

In some animals, however, notably certain fish, the living and healthy
organs are definitely poisonous. The family of Tetrodontidae (puffers,
balloon-fish, globe-fish) comprises a number of poisonous species,
including the famous Japanese _Fugu_, which has many hundred deaths
scored against it and has been often used to effect suicide. Poisonous
varieties of fish seem more abundant in tropical waters than in
temperate, but this is possibly because of the more general and
indiscriminate use of fish as food in such localities as the Japanese
and South Sea Islands. It is known that some cool-water fish are
poisonous. The flesh of the Greenland shark possesses poisonous
qualities for dogs and produces a kind of intoxication in these
animals.[29]

Much uncertainty exists respecting the conditions under which the
various forms of fish poisoning occur. One type is believed to be
associated with the spawning season, and to be caused by a poison
present in the reproductive tissues. The roe of the European barbel is
said to cause frequent poisoning, not usually of a serious sort. The
flesh or roe of the sturgeon, pike, and other fish is also stated to be
poisonous during the spawning season. Some fish are said to be poisonous
only when they have fed on certain marine plants.[30]

There is little definite knowledge about the poisons concerned. They are
certainly not uniform in nature. The _Fugu_ poison produces cholera-like
symptoms, convulsions, and paralysis. It is not destroyed by boiling.
The effect of the Greenland shark flesh on dogs is described as being
"like alcohol." It is said that dogs fed with gradually increasing
amounts of the poisonous shark's flesh become to some degree immune.
Different symptoms are described in other fish poisoning cases.[31]


FOOTNOTES:

[13] _Science_, XV (1902), 1016.

[14] _U.S. Dept. of Agric., Div. of Botany, Bull. 20_, 1898.

[15] Among the plants that seem to be most commonly implicated in the
poisoning of stock are the larkspur (_Delphinium._ _U.S. Dept. of
Agric., Bull. 365_, September 8, 1916), the water hemlock (_Cicuta
maculata_) and others of the same genus, the lupines (_U.S. Dept. of
Agric., Bull. 405_, 1916), some of the laurels (_Kalmia_), and the Death
_Camas_ or _Zygadenus_ (_U.S. Dept. of Agric., Bull. 125_, 1915). The
famous loco-weed of the western United States (_U.S. Dept. of Agric.,
Bull. 112_, 1909) is less certainly to be held responsible for all the
ills ascribed to it (H. T. Marshall, _Johns Hopkins Hosp. Bull._, XXV
[1914], 234).

[16] Chesnut, _U.S. Dept. of Agric., Div. of Botany, Bull. 20_, 1898, p.
17.

[17] _Ibid._, p. 28.

[18] _Ibid._, p. 45. The seeds of the castor-oil bean, which contain a
very powerful poison (ricin) allied to the bacterial toxins, have been
known to cause the death of children who ate the seeds given them to
play with.

[19] Mayer, _Deutsche Viertelj. f. öffentl. Ges._, XLV (1913), 12.

[20] Cf. an instance of palmolin poisoning, _Centralbl. f. Bakt._, I,
Ref., LXII (1914), 210.

[21] _Weekly Bull., N.Y. Dept. of Health_, September 16, 1916.

[22] Seventy-three species of mushrooms known or suspected to be
poisonous are enumerated in a bulletin of the United States Department
of Agriculture, Patterson and Charles ("Mushrooms and Other Common
Fungi," _Bull. 175_, 1915). This bulletin contains descriptions and
excellent illustrations of many edible and of the commoner poisonous
species.

[23] Used in some places as a fly poison.

[24] Ford, _Science_, XXX (1909), 97.

[25] Another species of mushroom occurring in this country and commonly
regarded as edible (_Panaeolus papilionaceus_) has on occasion shown
marked intoxicating properties (A. E. Verrill, _Science_, XL (1914),
408).

[26] _Jour. Infect. Dis._, III (1906), 191.

[27] _Jour. Amer. Med. Assoc._, LXIV (1915), 1230.

[28] W. W. Ford, "Plant Poisons and Their Antibodies," _Centralbl. f.
Bakt._, I Abt., Ref., LVIII (1913), 129 and 193, with full bibliography.

[29] A. H. Clark, _Science_, XLI (1915), 795.

[30] See W. M. Kerr, _U.S. Nav., Monthly Bull._, VI (1912), 401.

[31] _Ibid._



CHAPTER IV

MINERAL OR ORGANIC POISONS ADDED TO FOOD


Well-known mineral or organic poisons--"chemical poisons"--sometimes
find their way into food, being either introduced accidentally in the
process of manufacture or preparation, or being added deliberately with
intent to improve the appearance or keeping qualities of the food.


ARSENIC

So powerful a poison as arsenic has been occasionally introduced into
food by stupidity or carelessness. Arsenic has been found by English
authorities to be generally present in food materials dried or roasted
with gases arising from the combustion of coal, and in materials treated
with sulphuric acid during the process of preparation. In both cases the
source is the same: the iron pyrites, practically always arsenical,
contained in the coal or used in making the sulphuric acid.

A celebrated epidemic of "peripheral neuritis" in the English Midlands
in 1900 was traced to the presence of dangerous quantities of arsenic in
beer. About six thousand persons were affected in this outbreak and
there were some seventy deaths. The beer coming from the suspected
breweries had all been manufactured with the use of brewing sugars
obtained from a single source, and these sugars were found to have been
impregnated with arsenic by the sulphuric acid used in their
preparation, some specimens of the acid containing as much as 2.6 per
cent of arsenic.[32]

The use of glucose, not only in beer, but as an admixture or adulterant
in jams, syrups, candies, and the like, is open to serious objection
unless the glucose is known to have been prepared with sulphuric acid
freed from arsenical impurity. In fact, the use of any food material
prepared by the aid of sulphuric acid is permissible only in case
arsenic-free acid is employed.[33]


ANTIMONY

The cheaper grades of enameled cooking utensils in use in this country
contain antimony, and this is dissolved out in noteworthy amounts in
cooking various foods.[34] The rubber nipples used for infants' milk
bottles also sometimes contain antimony.[35] Although the poisonous
qualities of antimony are well known, there is little information about
the toxic effect of repeated very minute doses. Recognized instances of
chronic antimony poisoning are very rare. Further investigation is
needed.


LEAD

The well-known poisonousness of lead and its compounds prevents, as a
rule, the deliberate addition of lead salts to food substances, although
it is true that lead chromate is sometimes used for imparting a yellow
color to candy and decorating sugars.[36] Foods that are wrapped in
foil, however, such as chocolate and soft cheese, contain traces of
lead, as do the contents of preserve jars with metallic caps and the
"soft drinks" vended in bottles with patent metal stoppers. Occasional
ingestion of minute quantities of lead is probably a matter of little
physiological importance, but since lead is a cumulative poison,
frequent taking into the body of even very small amounts entails danger.
Severe lead poisoning has been known to result from the habitual use of
acid beverages contained in bottles with lead stoppers. Investigations
made to determine the possible danger of poisoning from lead taken up
from glazed and earthenware cooking utensils indicate that injury from
this source is unlikely. The enameled ware in common use in this country
is lead-free.

Objection on the ground of possible contamination has been raised to the
use of solder for sealing food cans. Such objections have less weight
than formerly owing to changes in the construction of the container, so
that any contact of solder with the food is now minimized and to a large
extent done away with altogether.

In consequence of the fact that many natural waters attack lead, the use
of lead service pipes for wells, cisterns, and public water supplies has
given rise to numerous outbreaks of lead poisoning. It is now generally
recognized that water intended for drinking purposes should not be drawn
through lead pipes.

A special liability to take lead into the stomach exists in persons
working at the painters' trade and other occupations involving contact
with lead and its salts. It has been shown that the eating of food
handled with paint-smeared hands brings about the ingestion of
considerable quantities of lead and, when long continued, results in
lead poisoning. The risk of contaminating food with lead in this way can
be greatly lessened by thorough cleansing of the hands with soap and hot
water before eating.[37]


TIN

Special interest has attached to the possibility of tin poisoning on
account of the widespread use of canned foods.[38] It is established
chemically that tin is attacked, not only by acid fruits and berries,
but by some vegetables having only a slightly acid reaction. More tin is
found in the drained solids than in the liquor, and the metal is largely
in an insoluble form.[39] It has been the general opinion based on
experiments by Lehmann[40] and others that the amounts of tin ordinarily
present in canned foods "are undeserving of serious notice," and this
view has found expression in the leading textbooks on hygiene.[41]
Certainly there has not been any noticeable amount of tin poisoning
observed coincident with the enormous increase in the use of canned
foods. An instance of poisoning by canned asparagus observed by
Friedmann,[42] however, is attributed by him to the tin content, and
this view is rendered probable by the negative result of his
bacteriological and serological examinations. Canned asparagus
apparently contains an unusually large amount of soluble tin
compounds.[43] There seems some ground for the assumption that certain
individuals are especially susceptible to small quantities of tin and
that the relative infrequency of such cases as that cited by Friedmann
can be best explained in this way. Lacquered or "enamel-lined" cans are
being used to an increasing extent for fruits and vegetables that are
especially likely to attack tin.[44]

Intentional addition of tin salts to food substances does not appear to
be common, although protochloride of tin is said sometimes to be added
to molasses for the purpose of reducing the color. The chlorides are
regarded as more definitely poisonous than other compounds of tin, and
for this and other reasons the practice is undesirable. Sanitarians
insist that chemical substances likely to be irritating to the human
tissues in assimilation or elimination should not be employed in food.
Each new irritant, even in small quantity, may add to the burden of
organs already weakened by age or previous harsh treatment.


COPPER

Danger is popularly supposed to attend the cooking and especially the
long standing of certain foods in copper vessels on account of the
verdigris or copper acetate that is sometimes formed, but Professor
Long, of the Referee Board of Consulting Scientific Experts,[45] points
out that this substance is far less toxic than it was once imagined to
be, and he considers it likely that the cases of illness attributed to
"verdigris poisoning" reported in the older literature should have been
explained in some other way.

The use of copper sulphate for imparting a green color to certain
vegetables, such as peas, beans, and asparagus, is a relatively modern
practice, having been started in France about 1850. Since the natural
green of vegetables is in part destroyed or altered by heat, restoration
of the color has appealed to the color sense of some consumers. It must
be admitted that this aesthetic gratification is fraught with some
degree of danger to health. The experiments by Long show that copper is
absorbed and retained in certain tissues, and that even small amounts
ingested at brief intervals may have a deleterious action. He concludes
that the use of copper salts for coloring foods must be considered as
highly objectionable. The United States Government now prohibits the
importation of foods colored with copper and also the interstate trade
in these substances.


VARIOUS COLORING SUBSTANCES

Copper sulphate is but one of a host of chemical substances applied to
various foods for the purpose of altering the color which the foods
would otherwise possess. In some cases perhaps it may be the general
opinion that by special treatment the attractiveness of a food product
is increased, as when dark-colored flour is bleached white with
nitrogen peroxide, but in many instances the modification of color is
based on preposterously artificial standards. The use of poisonous
aniline dyes for staining candies all the colors of the rainbow must be
defended, if at all, on aesthetic rather than on sanitary grounds. Some
coloring matters in common use, such as the annatto, universally
employed in coloring butter, are believed to be without harmful effect,
but others are to be viewed with suspicion, and still others, like
copper sulphate, are unquestionably dangerous. The whole practice of
food coloration at its best involves waste and may entail serious danger
to health. Broadly speaking, all modification of the natural color of
foodstuffs is based on an idle convention and should be prohibited in
the interest of the public welfare. Bleached flour, stained butter, dyed
jelly and ice-cream are no whit more desirable as foods than the natural
untreated substances; in fact, they are essentially less desirable. If
the whole process of food coloration were known to the public,
artificially colored foods would not be especially appetizing.
Economically the practice is singularly futile. The artificial whitening
of flour with the highly poisonous nitrogen peroxide seems hardly worth
the extra tax of fifty cents to a dollar a barrel. Such bleaching with a
poisonous gas certainly does not improve the nutritive or digestive
qualities of flour; it may be insidiously injurious. The solution of the
problem of food coloration seems to lie in a policy of educational
enlightenment which shall make natural foods appear more desirable than
those sold under false colors. Custom, however, buttressed by skilful
advertising, offers a difficult barrier to reform in this field.


FOOD PRESERVATIVES

It is not only legitimate, but in every way most desirable, to keep food
over from a season of superabundance to a season of scarcity. From time
immemorial food has been preserved by drying, smoking, or salting, and,
in modern times, by refrigeration and by heat (canning). These latter
methods have come to play a large part in the food habits of civilized
communities. Since food spoils because of microbic action, all methods
of preservation are based upon the destruction of the microbes or the
restraint of their growth by various physical and chemical agencies. The
use of certain chemical preservatives such as strong sugar and salt
solutions, saltpeter brines, and acid pickles has long been known and
countenanced. In recent times the employment of chemical preservatives
has acquired a new aspect through the increasing tendency of
manufacturers to add to food products antiseptic chemicals in wide
variety and of dubious physiological effect.

It is not so easy and simple as it might appear to declare that no
substance that is poisonous shall be added to food. The scientific
conception of a poison is one involving the amount as well as the kind
of substance. Common salt itself is poisonous in large doses, but, as
everyone knows, small amounts are not only not injurious, but absolutely
necessary to health. Well-known and very powerful protoplasmic poisons
such as strychnine and quinine are frequently administered in minute
doses for medicinal purposes, without causing serious results.

How complicated the question of using food preservatives really is
appears in the case of smoked meats and fish, which owe their keeping
qualities to the creosote and other substances with which they are
impregnated by the smoke. Although these substances are much more highly
poisonous than chemical preservatives like benzoic acid, over which much
concern has been expressed, but little if any objection has been made to
the use of smoked foods.

The use of benzoic acid (benzoate of soda) as a food preservative
illustrates several phases of the controversy. Observations by Wiley in
1908 upon so-called "poison squads" were thought by him to indicate that
benzoate of soda administered with food led to "a very serious
disturbance of the metabolic functions, attended with injury to
digestion and health." On the other hand, the experiments of the Referee
Board of Scientific Experts (1909), conducted with at least equal care
and thoroughness, were considered to warrant the conclusions that:

  (1) Sodium benzoate in small doses (under five-tenths of a gram per
  day) mixed with the food is without deleterious or poisonous action
  and is not injurious to health. (2) Sodium benzoate in large doses
  (up to four grams per day) mixed with the food has not been found to
  exert any deleterious effect on the general health, nor to act as a
  poison in the general acceptance of the term. In some directions
  there were slight modifications in certain physiological processes,
  the exact significance of which modification is not known. (3) The
  admixture of sodium benzoate with food in small or large doses has
  not been found to injuriously affect or impair the quality or
  nutritive value of such food.

Still later experiments under the auspices of the German government
(1913) showed that in the case of dogs and rabbits relatively large
doses of benzoic acid (corresponding to sixty to one hundred grams per
day for a man weighing one hundred and fifty pounds) were necessary in
order to produce demonstrable effects of any kind. This finding may be
considered to confirm in a general way the finding of the Referee Board
that four grams per day is harmless.

Probably the evidence respecting the effect of benzoic acids and the
benzoates when used as food preservatives constitutes as favorable a
case as can be made out at the present time for the employment of any
chemical substance. Benzoic acid is present in noteworthy amounts in
many fruits and berries, especially cranberries, and its presence in
these natural foods has never been connected with any injurious action.
In point of fact, substances present in many ordinary foodstuffs are
converted within the human body first into benzoic acid and then into
hippuric acid. Folin's masterly summing up is worth quoting:

  We know that the human organism is prepared to take care of and
  render harmless those small quantities of benzoic acid and benzoic
  acid compounds which occur in food products or which are formed
  within the body; we know how this is accomplished and are reasonably
  sure as to the particular organ which does it. We also know that the
  mechanism by means of which the poisonous benzoic acid is converted
  into the harmless hippuric acid is an extremely efficient one, and
  that it is capable of taking care of relatively enormous quantities
  of benzoic acid. In this case, as in a great many others, the normal
  animal organism is abundantly capable of performing the function
  which it must regularly perform in order to survive. From this point
  of view it can be argued, and it has been argued with considerable
  force, that the human organism is abundantly capable of rendering
  harmless reasonable amounts of benzoic acid or benzoate which are
  added for purposes of preservation to certain articles of our food.
  In my opinion this point of view is going to prevail, and the strife
  will resolve itself into a controversy over how much benzoic acid
  shall be permitted to go into our daily food.

  But we ought to be exceedingly cautious about accepting any definite
  figure, certainly any large figure, as representing the permissible
  amount of added benzoic acid in our food. The very fact that we are
  in possession of an efficient process for converting poisonous
  benzoic acid into harmless hippuric acid indicates that there is a
  necessity for doing so. It suggests that even the small quantities
  of benzoic acid which we get with unadulterated food, or produce
  within ourselves, might be deleterious to health except for the
  saving hippuric acid forming process. And because that "factor of
  safety" is a large one with respect to the normal benzoic acid
  content of our food it does not follow that we can encroach on it
  with perfect impunity. What the effect of a general, regular
  encroachment on it would be cannot be determined by a few relatively
  short feeding experiments. It is known that while certain chemicals
  may be taken in substantial quantities for a month or a year without
  producing demonstrably injurious effects, nevertheless the continued
  use of the same substances, even in smaller quantities, will
  eventually undermine the health. Perhaps the final solution of the
  benzoic acid problem could be best obtained directly from the people
  at large. If they were to consume benzoic acid as knowingly as they
  consume, for example, sodic carbonate in soda biscuits, or caffeine
  and theobromine in coffee and tea, it would not require more than a
  decade or two before we should have a well-defined and well-founded
  public opinion on the subject, at least in the medical
  profession.[46]

With respect to other familiar and more or less poisonous substances
used to preserve foods, defense of their harmlessness is far more
difficult. Formaldehyde, salicylic acid, sulphurous acid, and sulphite
are compounds definitely poisonous in relatively small amounts, their
injurious action in minute successive doses in animal experiments is
quite marked, and their use in human food products practically without
justification. Boric acid and borax are perhaps on a slightly different
footing, but are never present in natural foods, and there is no good
evidence that their long-continued ingestion in small doses is without
injurious effect. It must not be forgotten that all such substances owe
their preservative or antiseptic power to the poisonous effect they have
upon bacterial protoplasm. It is fair to assume that, in general,
bacterial protoplasm is no more easily injured than human protoplasm,
and this raises at once the propriety of bringing into repeated contact
with human tissues substances likely to produce injury even if such
injury is slight and recovery from it is ordinarily easy. In every case
the burden of proof should be properly placed on those who advocate the
addition of bacterial-restraining substances to food intended for human
consumption. It is for them to show that substances powerful enough to
hold in check the development of bacteria are yet unable to interfere
seriously with the life-processes of the cells of the human body.

When this view of the situation is taken, not only the chemical
substances mentioned previously fall under some suspicion, but also
certain household preservatives long sanctioned by custom. Spices such
as cinnamon, oil of cloves, and the like are, so far as we know, as
likely to have an injurious physiological effect when taken in small
recurring quantities as are some of the "chemical" preservatives whose
use is debarred by law. The chemicals deposited by wood smoke in meat
are of a particularly objectionable nature, and their continuous
ingestion may quite conceivably lead to serious injury.

One fact persistently comes to the front in any comprehensive study of
the food-preservative question, namely, the need of further experiment
and observation. We do not at present know what effect is produced in
human beings of different ages and varying degrees of strength by the
_long-continued_ consumption of food preserved with particular
chemicals.

  There is, I think, only one way to get at the facts with regard to
  the various chemicals which have been used for the preservation of
  foods, and that is by trying them and keeping track of the results.
  To try them properly, on a sufficiently extensive scale and for a
  sufficiently long time, is, however, more of a task than can be
  undertaken by private investigators; for it is only by their
  continuous use for many years under competent supervision and
  control that we can hope to attain adequate information for final
  conclusions. Work of this sort should be done and could very well be
  done at large government institutions, as, for example, among
  certain classes of prison inmates. I do not know how many life
  prisoners or long-term prisoners may be available, but there must be
  an abundance of them. They would make better subjects than students
  on whom to try out a substance like boric acid. This, not because
  they are prisoners whose fate or health is of comparatively little
  consequence, but because they represent a body of persons whose mode
  of life is essentially uniform and whose health record could easily
  be kept for a long period of years. I am well aware that this
  suggestion will impress many persons as heartless and brutal, but
  such an experiment would be a mild and humane one when compared with
  the unrecorded boric acid experiments which have been made by
  manufacturers on all kinds and conditions of people. Prisoners are
  unfortunate in not being able to render any useful service to
  society. Probably not a few would be willing to co-operate in
  prolonged feeding experiments, similar to the short ones conducted
  by Dr. Wiley and by the Referee Board. Acceptable reward in the way
  of well-prepared food of sufficient variety would attract
  volunteers. If additional inducement were necessary, shortened term
  of service would probably appeal to many. And in the face of the
  fact that every civilized country is prepared to sacrifice thousands
  of its most virile citizens for the honor of its flag (and its
  foreign trade), the sentiment against endangering the health of a
  handful of men in the interest of all mankind is not particularly
  intelligent.[47]

Until such information is forthcoming we do well to err on the side of
caution. The desirability of adopting this attitude is especially borne
in upon us by the facts already instanced (pp. 2-4) concerning the
increased death-rates in the higher-age groups in this country. For
aught we now know to the contrary, the relatively high death-rates from
degenerative changes in the kidneys, blood vessels, and other organs may
be in part caused by the use of irritating chemical substances in food.
Although no one chemical by itself and in the quantities in which it is
commonly present in food can perhaps be reasonably accused of producing
serious and permanent injury, yet when to its effect is superadded the
effect of still other poisonous ingredients in spiced, smoked, and
preserved foods of all kinds the total burden laid upon the excretory
and other organs may be distinctly too great. There can be no escape
from the conclusion that the more extensive and widespread the use of
preservatives in food the greater the likelihood of injurious
consequences to the public health.

The use of spoiled or decomposed food falls under the same head. It
cannot be assumed that the irritating substances produced in food by
certain kinds of decomposition can be continually consumed with
impunity. We do not even know whether these decomposition products may
not be more fundamentally injurious than preservatives that might be
added to prevent decomposition!

So far as our present knowledge indicates, therefore, effort should be
directed (1) to the purveying of food as far as possible in a fresh
condition; (2) to the avoidance of chemical preservatives of all kinds
except those unequivocally demonstrated to be harmless. The methods of
preserving food by drying, by refrigeration, and by heating and sealing
are justified by experience as well as on theoretical grounds, and the
same statement can be made regarding the use of salt and sugar
solutions. But the use of sulphites in sausage and chopped meat, the
addition of formaldehyde to milk, and of boric acid or sodium fluoride
to butter are practices altogether objectionable from the standpoint of
public health.

The remedy is obvious and has been frequently suggested--namely, laws
prohibiting the addition of any chemical to food except in certain
definitely specified cases. The presumption then would be--as in truth
it is--that such chemicals are more or less dangerous, and proof of
innocuousness must be brought forward before any one substance can be
listed as an exception to the general rule. Such laws would include not
only the use of chemicals or preservatives, but the employment of
substances to "improve the appearance" of foodstuffs. As already pointed
out, the childish practice of artificially coloring foods involves waste
and sometimes danger. It rests on no deep-seated human need; food that
is natural and untampered with may be made the fashion just as easily as
the color and cut of clothing are altered by the fashion-monger. The
incorporation of any chemical substance into food for preservative or
cosmetic purposes could wisely be subject to a general prohibition, and
the necessary list of exceptions (substances such as sugar and salt)
should be passed on by a national board of experts or by some
authoritative organization like the American Public Health Association.


FOOD SUBSTITUTES

On grounds of economy or convenience familiar and natural articles of
food are sometimes replaced or supplemented by artificial chemical
products, or by substances whose food value is not so definitely
established. I need refer only briefly to those notorious instances of
adulteration in which chicory is added to coffee, or ground olive stones
to pepper, or glucose to candy. On hygienic grounds alone some such
practices are not open to criticism, however fraudulent they may be from
the standpoint of public morals. It might be argued with some
plausibility that chicory is not so likely to harm the human organism as
caffeine and that sprinklings of ground cocoanut shell are more
wholesome than pepper. But there is another group of cases in which the
artificial substitute is strictly objectionable. The use of the coal-tar
product saccharin for sweetening purposes is an example. This substance,
whose sweetening power is five hundred times as great as that of cane
sugar, has no nutritive value in the quantities in which it would be
consumed, and in not very large quantities (over 0.3 gram per day) is
likely to induce disturbance of digestion. As a substitute for sugar in
ordinary foodstuffs it is undesirable.[48]

The use of cheap chemically prepared flavors such as "fruit ethers" in
"soft drinks," fruit syrups, and the like in place of the more expensive
natural fruit extracts affords another well-known instance of
substitution. Probably more important hygienically is the production of
"foam" in "soda water" by saponin, a substance known to be injurious for
red blood corpuscles.

Among the many other familiar examples of food substitution,
sophistication, and adulteration there are some of demonstrable hygienic
disadvantage and others whose chief demerit lies in simple deception. Of
practically all it may be said that they are indefensible from the
standpoint of public policy since they are based on the intent to make
foodstuffs appear other than what they really are.

It is the opinion of some who have closely followed the course of food
adulteration that, while the amount of general sophistication--legally
permissible and otherwise--has greatly increased in recent years, the
proportion of really injurious adulteration has fallen off. Be that as
it may, it is plain that the opportunity for wholesale experimentation
with new substances should not be allowed to rest without control in the
hands of manufacturers and dealers largely impelled by commercial
motives. So long as the motive of gain is allowed free scope, so long
will a small minority of unscrupulous persons add cheap, inferior, and
sometimes dangerous ingredients to foodstuffs. The net of restriction
must be drawn tighter and tighter. The motives leading to the tampering
with food fall mainly under three heads: (1) a desire to preserve food
from spoiling or deterioration; (2) a puerile fancy--often skilfully
fostered for mercenary reasons--for a conventional appearance, as for
polished rice, bleached flour, and grass-green peas; and (3) intent to
make the less valuable appear more valuable--deliberate fraud. Only the
first-named motive can claim any legitimate justification, and its
gratification by the use of chemical preservatives is surrounded with
hygienic difficulties and uncertainty, as already set forth. From the
unbiased view of human physiology the dangers of slow poisoning from
chemically treated foods must be regarded as no less real because they
are insidious and not easily traced.


FOOTNOTES:

[32] E. S. Reynolds, _Lancet_, I (1901), 166.

[33] The sulphuric acid used in making glucose in the United States is
authoritatively declared to be absolutely free from arsenic (report of
hearing before Illinois State Food Standard Commission, June 21-23,
1916; see _Amer. Food Jour._, July, 1916, p. 315).

[34] E. W. Miller, _Jour. Home Economics_, VIII (1916), 361.

[35] Phelps and Stevenson, _Hyg. Lab., U.S. Public Health Service, Bull.
96_, 1914, p. 55.

[36] Harrington and Richardson, _Manual of Practical Hygiene_, 5th ed.,
p. 224.

[37] See Alice Hamilton, "Hygiene of the Painters' Trade," _U.S. Bureau
of Labor Statistics, Bull. 120_, 1913.

[38] In 1909 the value of foods canned in the United States amounted to
about $300,000,000 (_U.S. Dept. of Agric., Bull. 196_, 1915).

[39] W. D. Bigelow, _Amer. Food Jour._, XI (1916), 461.

[40] _Arch. f. Hyg._, XLV (1902), 88; _ibid._, LXIII (1907), 67.

[41] See, e.g., Harrington and Richardson, _Practical Hygiene_, 5th ed.,
p. 274.

[42] _Ztschr. f. Hyg._, LXXV-LXXVI (1913-14), 55.

[43] Bigelow, _loc. cit._

[44] A. W. Bitting, _U.S. Dept. of Agric., Bull. 196_, 1915.

[45] _U.S. Dept. of Agric., Report 97_, 1913.

[46] Folin, _Preservatives and Other Chemicals in Foods_ (Harvard
University Press, 1914), p. 32.

[47] Folin, _op. cit._, p. 42.

[48] See _U.S. Dept. of Agric., Report 94_, 1911.



CHAPTER V

FOOD-BORNE PATHOGENIC BACTERIA


Many cases of so-called food poisoning are due to the presence of
pathogenic bacteria in the food. In some instances, as in the typical
meat poisoning epidemics, symptoms develop so soon after eating that the
particular food involved is immediately suspected and laid hands on. In
other cases the guilty article of food is difficult to trace. Certain
cases of tuberculosis are undoubtedly caused by swallowing tubercle
bacilli in the food, but the precise source and date of infection can be
rarely, if ever, certainly established.

The presence of pathogenic bacteria in food is usually due either to the
contamination of the food by infected human beings during the process of
preparation or serving, or to an infection of the animal from which the
food is derived. The relative importance of these two factors is quite
different in the various infections.


TYPHOID FOOD INFECTION

The typhoid bacillus does not attack any of the domestic animals;
consequently all food-borne typhoid is caused more or less directly by
human contamination. A remarkable instance of typhoid infection due to
food was reported in 1914 in Hanford, California, where ninety-three
typhoid cases were caused by eating Spanish spaghetti served at a public
dinner.[49] Investigation showed that this dish was prepared by a woman
typhoid-carrier who was harboring living typhoid bacilli at the time
she mixed the sauce for the spaghetti before baking. Further laboratory
experiments indicated that the ordinary baking temperature at which the
spaghetti was cooked was not only not sufficient to sterilize the food,
but afforded a favorable opportunity for the bacteria in the interior of
the mass to multiply. The infection of the food was consequently heavy
and involved a very large proportion (57 per cent) of those present at
the dinner.

Merited celebrity attaches to the exploits of the typhoid-carrier, Mary
Malloy, who, in pursuing her career as cook in and about New York City,
is known to have caused at least seven typhoid outbreaks in various
families in which she worked and one extensive hospital epidemic.
Similar cases of typhoid food infection by employees in restaurants and
public institutions are by no means uncommon, and show the necessity of
protecting food from contamination during the whole process of
preparation and serving. Acting on this principle, the Department of
Health of New York City has inaugurated a comprehensive examination of
the cooks and waiters (approximately 90,000) employed in the public
restaurants and dining-rooms in that city. Results have been obtained in
the discovery of typhoid-carriers and of cases of communicable disease
that amply justify this procedure as an important measure for protecting
the community against the dissemination of infection.

Some foods by their origin are exposed more than others to typhoid
contamination. Such vegetables as lettuce, celery, radishes, and
watercress, which are commonly eaten without cooking, are more likely
to convey typhoid than peas, beans, and potatoes. A typhoid outbreak
apparently due to watercress has been reported from Philadelphia.[50] At
a wedding breakfast to forty-three guests on June 24, 1913, watercress
sandwiches were served, and subsequent inquiry showed that nineteen of
the guests partook of these sandwiches. Eighteen of this number became
ill with typhoid fever within a month, the illness developing in most
cases after the guests had scattered to their summer homes. Those who
did not eat watercress sandwiches were not affected. Typhoid infection
by uncooked celery has also been reported.[51]

The practice of using human excreta as fertilizer in truck gardens is
sometimes responsible for a dangerous contamination of the soil, which
is communicated to the growing plants and persists for a long time.[52]
Even scrupulous washing of vegetables is not sufficient to render them
bacterially clean. In the future the danger to the community from this
source is likely to become increasingly serious unless the growing use
of this method of soil enrichment is definitely checked.

In 1915 an increasing number of typhoid cases in South Philadelphia led
to an investigation by the state health department.[53] This disclosed
the fact that the majority of the cases were clustered in and about
three public markets.

  These are all curb markets--fruits, vegetables, pastry, clothing,
  and miscellaneous merchandise of every description are dumped on
  push-carts and pavements without regard for any sanitary
  precautions. The patrons of these markets handle and pick over the
  exposed foodstuffs, thus giving every opportunity for the
  transmission of disease....

  The greatest number of cases occurred in the immediate vicinity of
  the Christian Street Market. This market is largely patronized by
  the inhabitants of the section known as "Little Italy." The patrons
  of the South Street Market are principally Hebrews, while the
  Seventh Street Market is patronized in the main by Hebrews
  and Poles.

The following conclusion was reached regarding the particularly large
number of cases among persons of one nationality:

  Our inspectors have found that the different methods used by the
  Italians and Hebrews in the preparation of their food are
  responsible for the larger number of cases being found in the
  vicinity of the Christian Street Market in Little Italy. It is the
  custom of the Italians to eat many of the fruits and vegetables raw,
  while the Hebrews cook the greater portion of their food. It is
  presumably due to this custom that the members of the Italian
  colony have suffered to a greater extent than the other residents
  of the district.

A bacterial examination of various kinds of vegetables obtained from
push-carts and curb markets led to the finding of the typhoid bacillus
upon some of the celery. It would naturally be difficult to determine in
such cases whether the typhoid bacilli were derived from infected soil
in which the celery was grown or whether the contamination occurred
through improper handling.

Bread, when marketed unwrapped, is subject to contamination from flies
and from uncleanly handling. Katherine Howell[54] has shown that
unwrapped loaves of bread sold in Chicago were more or less thickly
smeared with bacteria and were coated on the average with a much larger
number than wrapped loaves. In some cases typhoid fever has been
directly traced to bread. Hinton[55] has recorded the occurrence of
seven typhoid cases in the Elgin (Illinois) State Hospital, which were
apparently due to a typhoid-carrier whose duty it was as attendant to
slice the bread before serving. When this typhoid-bearing attendant was
transferred to another department where she handled no uncooked food,
cases of typhoid ceased to appear.[56]

Food such as milk that is not only eaten customarily without cooking,
but is also suitable for the growth of typhoid bacilli, needs to be
particularly safeguarded. It is noteworthy that the compulsory
pasteurization of milk in New York, Chicago, and other large American
cities has been accompanied by a great diminution in the prevalence of
typhoid fever. Until recent years milk-borne typhoid in the United
States has been common and hundreds of typhoid epidemics have been
traced to this source.

[Illustration: FIG. 5.--Bacteria left by fly passing over gelatin plate.
(By courtesy of Doubleday, Page & Company.)]

One food animal, the oyster, frequently eaten raw, has been connected on
good evidence with certain typhoid outbreaks.[57] The number of
well-established oyster typhoid epidemics is not great, however, and
the danger from this source has sometimes been exaggerated. The source
of oyster contamination is in sewage pollution either of the shellfish
beds or of the brackish water in which the oyster is sometimes placed to
"fatten" before it is marketed. State and federal supervision of the
oyster industry in the United States in recent years has largely done
away with the taking of oysters from infected waters, and although
oysters--and clams and mussels as well--must be steadily safeguarded
against sewage contamination, the actual occurrence of oyster infection
at the present time is believed to be relatively rare.

Probably the most effective method of preventing typhoid food infection
is to investigate every case of typhoid fever and trace it, so far as
practicable, to its origin. In this way typhoid-carriers may be
discovered and other foci of infection brought to light. Carriers, once
found, may be given proper advice and warned that they constitute a
danger to others; the complete control of typhoid-carriers who are not
disposed to act as advised is a difficult problem and one not yet solved
by public health authorities.


ASIATIC CHOLERA

With Asiatic cholera, just as with typhoid fever, domestic animals are
not susceptible to the disease, all cases of infection having a direct
human origin. Drinking-water is the usual vehicle of cholera infection,
and even in countries where the disease is endemic, food-borne outbreaks
of this disease are far less common than those of typhoid fever.
Occasional instances of Asiatic cholera due to milk supply and to
contaminated fruits or lettuce are on record, but these are exceptional
and cannot be regarded as exemplifying a common mode of spread of this
disease. The extent, however, to which dwellers in tropical
countries--and indeed in all lands--are at the mercy of their household
helpers is illustrated by the following experience of the English
bacteriologist, Hankin. "I have seen," he says, "a cook cooling a jelly
by standing it in a small irrigation ditch that ran in front of his
cookhouse. The water running in this drain came from a well in which I
had detected the cholera microbe. He cleaned a spoon by dipping it in
the drain and rubbing it with his fingers; then he used it to stir the
jelly."[58]


TUBERCULOSIS

Animal experiments have shown that both meat and milk derived from
tuberculous cattle are capable of conveying infection. The precise
degree of danger to human beings from the use of these foods under
modern conditions is still in dispute. Since the tubercle bacillus of
bovine origin differs from the tubercle bacillus of human origin in
certain well-defined particulars, it is possible by careful study to
distinguish the human infections caused by the bovine bacillus from
those caused by the so-called human tubercle bacillus. Additional
comparative investigations are needed in this field, and these may
enable us to estimate eventually more fully than is possible at present
the extent of human tuberculous infection derived from bovine sources.

Meat is a less likely source of infection than milk, chiefly because it
is rarely eaten without cooking. Opinion regarding the actual frequency
of the transmission of tuberculosis by means of the meat of tuberculous
cattle has been widely at variance in the past, and must even now be
based on indirect evidence. There is no well-established instance of
human infection from the use of the flesh of tuberculous cattle. The
significance of this fact, however, is diminished by the observation
that tubercle bacilli can pass through the intestinal wall without
leaving any trace of their passage and can make their way to the lungs
or to other distant organs where they find opportunity for growth. This,
together with the long period which usually elapses between the actual
occurrence of infection and the discovery of the existence of infection,
makes the difficulty of securing valid evidence peculiarly great.
Opposed to any very frequent occurrence of meat-borne tuberculosis are
the facts that the tubercle bacillus is not commonly or abundantly
present in the masses of muscle usually marketed as "meat," that the
tubercle germ itself is not a spore-bearer and is killed by ordinary
cooking, and that the reported cases of the finding of tubercle bacilli
of bovine origin in adults over sixteen years of age are extremely rare.
This latter fact is perhaps the strongest evidence indicating that
tuberculous meat infection, although theoretically possible, is at least
not of common occurrence.

Most of the commissions and official agencies that have considered the
precautions to be taken against possible tuberculous meat infection are
agreed that the entire carcass of an animal should be condemned when the
tuberculous lesions are generalized or when the lesions are extensive in
one or both body cavities as well as when the lesions are "multiple,
acute, and actively progressive." Any organ showing evidence of
tuberculous lesions is obviously not to be passed as food. On the other
hand, it is considered that portions of properly inspected animals may
be put on the market if the tuberculous lesion is local and limited and
the main part of the body is unaffected; in such cases contamination of
the meat in dressing must be avoided. It is the general belief that
when such precautionary measures are taken the danger of tuberculous
infection through properly cooked meat is so slight as to be negligible.

Milk is a much more likely vehicle than meat for the transmission of
tuberculosis. Freshly drawn raw milk from tuberculous cattle may contain
enormous numbers of tubercle bacilli, especially if the udder is
diseased. Contamination of milk by the manure of tuberculous cows can
also occur. Observers in England, Germany, France, and the United States
have found tubercle bacilli in varying numbers in market milk, and have
proved that such milk is infectious for laboratory animals. Although, as
pointed out with reference to meat infection, the difficulties of
tracing any particular case of tuberculosis to its source are very
great, there are a number of instances on record in which the
circumstantial evidence strongly indicates that milk was the vehicle of
infection. Especially convincing are the observations on the relative
frequency of infection with bovine and human tubercle bacilli at
different ages as shown in the following tabulation:[59]

  ====================================================================
                      |Adults Sixteen|Children Five to|Children under
                      | Years Old    | Sixteen Years  |  Five Years
                      | and Over     |      Old       |
  --------------------+--------------+----------------+--------------
  Human tubercle      |    677       |      99        |     161
    bacilli found     |              |                |
  Bovine tubercle     |      9       |      33        |      59
    bacilli found     |              |                |
  -------------------------------------------------------------------

The large proportion of bovine tubercle bacillus infections in children
stands in all probability in causal relation to the relatively extensive
use of raw milk in the child's dietary.

The proper pasteurization of milk affords a safe and reasonably
satisfactory means of preventing tuberculous infection from this source.
The general introduction of the pasteurizing process in most American
cities has ample justification from the standpoint of the prevention of
infection.


VARIOUS MILK-BORNE INFECTIONS

The facts related in the foregoing pages indicate that of all foods milk
is the most likely to convey disease germs into the human body. This is
partly due to the fact that milk is sometimes obtained from diseased
animals, and partly to the fact that unless great care is taken it may
readily become contaminated during the process of collection and
transportation; if milk is once seeded with dangerous bacteria these can
multiply in the excellent culture medium it affords. It is also partly
because milk is commonly taken into the alimentary tract without being
cooked. For these reasons the amount of illness traceable to raw milk
far exceeds that ascribable to any other food.

There are several infections that may be communicated by milk, but are
rarely if ever due to other foodstuffs. Diphtheria and scarlet fever are
perhaps the best known of these. Both diseases have been repeatedly
traced to the use of particular milk supplies, although various forms of
individual contact also play a large rôle in their dissemination.
Milk-borne scarlet fever and diphtheria seem to be generally, if not
always, due to the direct contamination of the milk from human sources.
It is considered possible, however, by some investigators that the cow
may sometimes become infected from human sources with the virus of
scarlet fever or diphtheria and may herself occasionally contribute
directly to the infection of the milk.

A serious milk-borne disease, which has lately been conspicuous in
Boston, Chicago, Baltimore, and other American cities under the name of
"septic sore throat" or "streptococcus sore throat," originates
apparently in some cases from infection of the udder of the cow by an
infected milker; in other cases the milk has seemingly been directly
infected by a human "carrier." The specific germ is thought to have been
isolated and its connection with the disease demonstrated in the
laboratory. This disease, like diphtheria and scarlet fever, is
sometimes due to contact. It is not known to be caused by any food
except milk.

Foot-and-mouth disease of cattle is transmissible to man through the
milk of infected cattle, but this infection in man is not very common or
as a rule very serious. So far as known, it is not communicated to man
in any other way except through the use of uncooked milk.

Such cases of infection or "poisoning" by milk may be prevented, as
already stated, by the exclusive use of heated milk. The possible
occurrence of nutritional disturbances (e.g., scurvy) in a small
proportion of the children fed on pasteurized or boiled milk is
considered by many physicians to be easily remedied and to possess much
less practical importance than the avoidance of infection.


POSSIBLE INFECTION WITH B. PROTEUS

One widely distributed organism known as _Bacillus proteus_ has been
several times held responsible for food poisoning outbreaks, but it is
not yet certain how far this accusation is justified. _B. proteus_ is
related to _B. coli_, but most varieties do not ferment lactose and are
much more actively proteolytic than the latter organism, as shown by
their ability to liquefy gelatin and casein. Like _B. coli_, they form
indol and ferment dextrose with gas production. Varieties of _B.
proteus_ are found widely distributed in decomposing organic matter of
all sorts.

The evidence upon which this bacillus is regarded as the cause of food
poisoning is not altogether convincing. The outbreak described by
Pfuhl[60] is typical. Eighty-one soldiers in a garrison at Hanover were
suddenly attacked with acute gastro-enteritis four to twelve hours after
eating sausage meat. The meat was found to contain _B. proteus_ in large
numbers, although it was prepared with ordinary care and was entirely
normal in appearance, taste, and smell. Rats and mice fed with the
sausage became ill and _B. proteus_ was isolated from the blood and
internal organs. But these animals sometimes die when fed with quite
normal meat, and _B. proteus_ and other common intestinal bacteria are
often isolated from the body after death. _B. proteus_, in fact, is
found in many animal foods and in the apparently normal human intestine.
Like _B. coli_, it frequently invades the internal organs after or
shortly before death. Finding _B. proteus_ in food or in the internal
organs does not therefore constitute definite proof of any causal
relationship. The evidence attributing other outbreaks to infection with
_B. proteus_ is similarly inconclusive.

It is equally uncertain whether the production of a poison in food by
this species can in any degree be held responsible for meat poisoning.
_B. proteus_ is common enough in decomposing food material and under
certain circumstances is known to generate substances that are toxic for
man. It is possibly true that toxic substances are produced in the early
stages of decomposition by this organism. In the opinion of Mandel[61]
and others, if any injurious effect at all is to be attributed to _B.
proteus_, it is in the nature of an intoxication and not an infection
(see chapter viii). So far as the existing evidence goes, the question
of the responsibility of this organism for food poisoning is still an
open one.


FOOTNOTES:

[49] Sawyer, _Jour. Amer. Med. Assoc._, LXIII (1914), 1537.

[50] _Eng. News_, LXX (1913), 322.

[51] Morse, _Report of State Board of Health of Mass._, 1899, p. 761.

[52] R. H. Creel, _Reprint from Public Health Reports, No. 72_,
Washington, 1912.

[53] _Health Bull. No. 76, Pennsylvania State Department of Health_,
December, 1915.

[54] _Amer. Jour. Public Health_, II (1912), 321.

[55] _Institution Quarterly_, III (1912), 18.

[56] See also a similar instance reported by Lumsden, _Hyg. Lab., U.S.
Public Health and Marine Hosp. Service, Bull. 78_, p. 165.

[57] For a discussion of the oyster question see G. W. Fuller, _Jour. of
Franklin Institute_, August, 1905; _N.Y. City Dept. of Health, Monthly
Bull._, November, 1913, and May, 1915; H. S. Cumming, _U.S. Public
Health Service, Pub. Health Bull. 74_, March, 1916.

[58] _Lancet_, II (1895), 46.

[59] Park and Krumwiede, _Jour. Med. Research_, N.S., XVIII (1910), 363.

[60] _Ztschr. f. Hyg._, XXXV (1900), 265.

[61] _Centralbl. f. Bakt._, I, Orig., LXVI (1912), 194.



CHAPTER VI

FOOD-BORNE PATHOGENIC BACTERIA (_Continued_)


PARATYPHOID INFECTION

The most characteristic examples of "food poisoning," popularly
speaking, are those in which the symptoms appear shortly after eating
and in which gastro-intestinal disturbances predominate. In the typical
group-outbreaks of this sort all grades of severity are manifested, but
as a rule recovery takes place. The great majority of such cases that
have been investigated by modern bacteriological methods show the
presence of bacilli belonging to the so-called paratyphoid group (_B.
paratyphosus_ or _B. enteritidis_). Especially is it true of meat
poisoning epidemics that paratyphoid bacilli are found in causal
relation with them. Hübener[62] enumerates forty-two meat poisoning
outbreaks in Germany in which bacilli of this group were shown to be
implicated, and Savage[63] gives a list of twenty-seven similar
outbreaks in Great Britain. In the United States relatively few
outbreaks of this character have been placed on record, but it cannot be
assumed that this is due to their rarity, since no adequate
investigation of food poisoning cases is generally carried out in our
American communities.

_Typical paratyphoid outbreaks._--Kaensche[64] describes an outbreak at
Breslau involving over eighty persons in which chopped beef was
apparently the bearer of infection. The animal from which the meat came
had been ill with severe diarrhea and high fever and was slaughtered as
an emergency measure (_notgeschlachtet_). On examination a pathological
condition of the liver and other organs was noted by a veterinarian who
declared the meat unfit for use and ordered it destroyed. It was,
however, stolen, carried secretly to Breslau, and portions of it were
distributed to different sausage-makers, who sold it for the most part
as hamburger steak (_Hackfleisch_). The meat itself presented nothing
abnormal in color, odor, or consistency. Nevertheless, illness followed
in some cases after the use of very small portions. With some of those
affected the symptoms were very severe, but there were no deaths.
Bacilli of the _Bacillus enteritidis_ type were isolated from the meat.

A large and unusually severe outbreak reported by McWeeney[65] occurred
in November, 1908, among the inmates of an industrial school for girls
at Limerick, Ireland. There were 73 cases with 9 deaths out of the total
number of 197 pupils. The brunt of the attack fell on the first or
Senior class comprising 67 girls between the ages of thirteen and
seventeen. Out of 55 girls belonging to this class who partook of beef
stew for dinner 53 sickened, and 8 of these died. One of the two who
were not affected ate the gravy and potatoes but not the beef. Some of
the implicated beef was also eaten as cold meat by girls in some of the
other classes, and also caused illness. Part of the meat had been eaten
previously without producing any ill effects. "The escape of those who
partook of portions of the same carcass on October 27 and 29 [five days
earlier] may be accounted for either by unequal distribution of the
virus, or by thorough cooking which destroyed it. Some of the infective
material must, however, have escaped the roasting of the 29th, and,
multiplying rapidly, have rendered the whole piece intensely toxic and
infective during the five days that elapsed before the fatal Tuesday
when it was finally consumed." The animal from which the fore quarter of
the beef was taken had been privately slaughtered by a local butcher. No
reliable information could be obtained about the condition of the calf
at, or slightly prior to, slaughter. The meat, however, was sold at so
low a price that it was evidently not regarded as of prime quality. In
this outbreak the agglutination reactions of the blood of the patients
and the characteristics of the bacilli isolated showed the infection to
be due to a typical strain of _Bacillus enteritidis_.

An epidemic of food poisoning occurred in July, 1915, at and near
Westerly, Rhode Island.[66] The outbreak was characterized by the usual
symptoms of acute gastro-enteritis, and followed the eating of pie which
was obtained at a restaurant in Westerly. All the circumstances of the
outbreak showed that a particular batch of pies was responsible. About
sixty persons were made seriously ill and four died. There was no
unusual taste or odor to the pies to excite suspicion. The symptoms
followed the eating of various kinds of pie: custard, squash, lemon,
chocolate, apple, etc., that had been made with the same pie-crust
mixture. _Bacillus paratyphosus_ B was isolated from samples of pie
that were examined. No definite clue was obtained as to the exact source
of infection of the pie mixture. It is possible that the pie became
infected in the restaurant through the agency of a paratyphoid-carrier,
but since there had been no change in the personnel of the restaurant
for several months, this explanation is largely conjectural. Possibly
some ingredient of animal origin was primarily infected.

_General characters of paratyphoid infection._--The symptoms of
paratyphoid food infection are varied. As a rule the first signs of
trouble appear within six to twelve hours after eating, but sometimes
they may come on within half an hour, or they may not appear until after
twenty-four to forty-eight hours. Gastro-intestinal irritation is
practically always present, and may take the form of a mild
"indigestion" or slight diarrhea or may be of great severity accompanied
with agonizing abdominal pain. Fever is usual, but is generally not very
high. Recovery may occur quickly, so that within two or three days the
patient regains his normal state, or it may be very slow, so that the
effects of the attack linger for weeks or months.

Investigators have noted the occurrence of at least two clinical types
of paratyphoid infection, the commoner gastro-intestinal type just
described and a second type resembling typhoid fever very closely, and
occasionally not to be distinguished from it except by careful bacterial
examination. It is not yet clear how these two clinical varieties are
related to the amount and nature of the infecting food material. No
difference in the type of paratyphoid bacillus has been observed to be
associated with the difference in clinical manifestation. Possibly the
amount of toxin present in the food eaten as well as the number of
bacilli may exercise some influence. The individual idiosyncrasy of the
patient doubtless plays a part.

While there is still some uncertainty about particular features of
paratyphoid infection, a few significant facts have been clearly
established: (1) Certain articles of diet are much more commonly
associated than others with this type of food poisoning. The majority of
recorded outbreaks are connected with the use of meat, milk, fish, and
other protein foods. Vegetables and cereals have been less commonly
implicated, fruits rarely. (2) In many, though not all, of the cases of
paratyphoid meat poisoning it has been demonstrated that the meat
concerned has been derived from an animal slaughtered while ailing
(_notgeschlachtet_, to use the expressive German term). There seems
reason to believe that in such an animal, "killed to save its life," the
specific paratyphoid germ is present as an infection before death. Milk
also has caused paratyphoid poisoning and in certain of these cases has
been found to be derived from a cow suffering from enteritis or some
other disorder. (3) There is evidence that originally wholesome food may
become infected with paratyphoid bacilli during the process of
preparation or serving in precisely the same way that it may become
infected with typhoid bacilli; the handling of the food by a
paratyphoid-carrier is commonly responsible for this. In a few instances
the disease is passed on from case to case, but this mode of infection
seems exceedingly rare and is not nearly so frequent as "contact"
infection in typhoid. (4) The majority of paratyphoid outbreaks are
associated with the use of uncooked or partly cooked food. A selective
action is often manifested, those persons who have eaten the
incriminated food substance raw or imperfectly cooked being most
seriously affected, while those who have partaken of the same food after
cooking remain exempt.

[Illustration: FIG. 6.--_Bacillus enteritidis_, Gärtner; pure culture;
Van Ermengem preparation. (Kolle and Wassermann.)]

The discovery of the connection of paratyphoid bacilli with meat
poisoning dates from the investigation by Gärtner,[67] in 1888, of a
meat poisoning outbreak in Frankenhausen, a small town in Germany. This
epidemic was traced to the use of meat from a cow that was slaughtered
because she was ill with a severe enteritis. Fifty-eight persons were
affected in varying grades of severity; the attack resulted fatally in
one young workman who ate about eight hundred grams of raw meat. Gärtner
isolated from the spleen of the fatal case and also from the flesh and
intestines of the cow a bacillus to which he gave the name _B.
enteritidis_. Inoculation experiments showed it to be pathogenic for a
number of animal species. Bacilli with similar characters have since
been isolated in a number of other meat poisoning epidemics in Germany,
Belgium, France, and England. One well-studied instance of food
poisoning due to the paratyphoid bacillus has been reported in the
United States.[68]

The bacteria of the paratyphoid group are closely related to the true
typhoid bacillus, but differ from the latter organism in being able to
ferment glucose with gas production. They are more highly pathogenic for
the lower animals than is the typhoid bacillus, but apparently somewhat
less pathogenic for man. Most types of paratyphoid bacilli found in food
poisoning produce more or less rapidly a considerable amount of alkali,
and, if they are inoculated into milk containing a few drops of litmus,
the milk after a time becomes a deep blue color. Several distinct
varieties of paratyphoid bacilli have been discovered. The main
differences shown by these varieties are agglutinative differences. That
is, the blood serum of an animal that has been inoculated with a
particular culture or strain will agglutinate that strain and also other
strains isolated from certain other meat poisoning epidemics, but will
not agglutinate certain culturally similar paratyphoid bacteria found in
connection with yet other outbreaks. Except in this single matter of
agglutination reaction, no constant distinction between these varieties
has been demonstrated. The clinical features of the infections produced
in man and in the higher animals by the different varieties seem to be
very similar if not identical.

The bacillus discovered by Gärtner (_loc. cit._) and known as _B.
enteritidis_ or Gärtner's bacillus is commonly taken as the type of one
of the agglutinative varieties. Bacilli with all the characters of
Gärtner's bacillus have been found in meat poisoning epidemics in
various places in Belgium and Germany. Mayer[69] has compiled a list of
forty-eight food poisoning outbreaks occurring between 1888 and 1911 and
attributed to _B. enteritidis_ Gärtner. These outbreaks comprised
approximately two thousand cases and twenty deaths. In twenty-three of
the forty-eight outbreaks the meat was derived from animals known to be
ill at the time, or shortly before, they were slaughtered. Sausage and
chopped meat of undetermined origin were responsible for eleven of the
remaining twenty-five outbreaks. Two of the _B. enteritidis_ outbreaks
were attributed to _Vanille Pudding_; one, to potato salad.

In other food poisoning outbreaks a bacillus is found which is
culturally similar to the Gärtner bacillus, but refuses to agglutinate
with the Gärtner bacillus serum. Its cultural and agglutination
reactions are almost, if not quite, identical with those of the bacilli
found in human cases of paratyphoid fever which have no known connection
with food poisoning. Mayer[70] gives a list of seventy-seven outbreaks
of food poisoning (1893-1911) in which organisms variously designated as
"_B. paratyphosus_ B" or as "_B. suipestifer_" were held to be
responsible. The total number of cases (two thousand) and deaths
(twenty) is about the same as ascribed to _B. enteritidis_. According to
Mayer's tabulation meat from animals definitely known to be ailing is
less commonly implicated in this type (ten in seventy-seven) than in _B.
enteritidis_ outbreaks (twenty-three in forty-eight). Sausage and
chopped meat of unknown origin, however, were connected with eighteen
outbreaks.

The bacillus named _B. suipestifer_ was formerly believed to be the
cause of hog cholera, but it is now thought to be merely a secondary
invader in this disease; it is identical with the bacillus called _B.
paratyphosus_ B in its cultural and to a large extent in its
agglutinative behavior, but is regarded by some investigators as
separable from the latter on the basis of particularly delicate
discriminatory tests. Bainbridge, Savage, and other English
investigators consider indeed that the true food poisoning cases should
be ascribed to _B. suipestifer_ and would restrict the term _B.
paratyphosus_ to those bacteria causing "an illness clinically
indistinguishable from typhoid fever." German investigators, on the
other hand, regard _B. suipestifer_ and _B. paratyphosus_ B as
identical. My own investigations[71] indicate that there is a real
distinction between these two types.

Bearing directly on this question is the discussion concerning the
distribution of the food poisoning bacilli in nature. Most investigators
in Germany, where the majority of food poisoning outbreaks have
occurred, or at least have been bacteriologically studied, are of the
opinion that _B. suipestifer_ (the same in their opinion as _B.
paratyphosus_ B) is much more widely distributed than _B. enteritidis_
and that it occurs, especially in certain regions, as in the southern
part of the German Empire, quite commonly in the intestinal tract of
healthy human beings. Such paratyphoid-carriers, it is supposed, may
contaminate food through handling or preparation just as
typhoid-carriers are known to do. A number of outbreaks in which
contamination of food during preparation is thought to have occurred
have been reported by Jacobitz and Kayser[72] (vermicelli),
Reinhold[73] (fish), and others. Reinhold notes that in one outbreak
several persons who had nursed those who were ill became ill themselves,
indicating possible contact infection. In another outbreak also reported
by Reinhold it was observed that those who partook of the infected food,
in this case dried codfish, on the first day were not so severely
affected as those who ate what was left over on the second day. A
bacillus belonging to the paratyphoid group was isolated from the stools
of patients, but not from the dried codfish. These facts were
interpreted as signifying that the fish had become infected in the
process of preparation and that the bacilli multiplied in the food while
it was standing.

There seems no doubt that certain cases of paratyphoid food poisoning
are caused by contamination of the food during preparation and are,
sometimes at least, due to infection by human carriers. The bacilli in
such cases are usually (according to many German investigators) or
always (according to most English bacteriologists) of the _B.
suipestifer_ type. Other cases are due to pathogenic bacteria derived
from diseased animals, and these bacteria are often, possibly always, of
a slightly different character (_B. enteritidis_ Gärtner). It is still
unsettled whether both types of food poisoning bacteria are always
associated with disease processes of man or animals, or whether they are
organisms of wide distribution which may at times acquire pathogenic
properties. In certain regions, as in North Germany and England, such
bacteria are rarely, if ever, found except in connection with definite
cases of disease. In parts of Southwest Germany, on the other hand, they
are said to occur with extraordinary frequency in the intestines of
healthy men and animals. Savage[74] believes that there is some
confusion on this subject owing to the existence of saprophytic bacteria
which he calls "Paragaertner" forms and which bear a close resemblance
to the "true" Gärtner bacilli. They can be distinguished from the latter
only by an extended series of tests. The bacilli of this group show
remarkable variability, and in the opinion of some investigators
"mutations" sometimes occur which lead to the transformation of one type
into another.[75]

In spite of the present uncertainty regarding the relationship and
significance of the varieties observed, a few facts emerge plainly from
the confusion: (1) The majority of meat poisoning outbreaks that have
been bacterially studied in recent years have been traceable to one or
another member of this group and not to "ptomain poisoning." (2)
Bacteria of the _paratyphoid enteritidis_ group that are culturally
alike but agglutinatively dissimilar can, when taken in with the food,
give rise to identical clinical symptoms in man. (3) Food poisoning
bacteria of this group, when derived directly from diseased animals,
seem more likely to be of the Gärtner type (_B. enteritidis_) than of
the _B. suipestifer_ type.

_Toxin production._--The problem of the production of toxin by the
bacteria of this group and the possible relation of the toxin to food
poisoning has been much discussed. Broth cultures in which the living
bacilli have been destroyed by heat or from which they have been removed
by filtration contain a soluble poison. When this germ-free broth is
injected into mice, guinea-pigs, or rabbits, the animals die from the
effects. Practically nothing is known about the nature of the poisonous
substances concerned, except that they are heat-resistant. They are
probably not to be classed with the so-called true toxins generated by
the diphtheria and tetanus bacilli, since there is no evidence that they
give rise to antibodies when injected into susceptible animals. In the
opinion of some investigators the formation of these toxic bodies by the
_paratyphoid-enteritidis_ bacilli in meat and other protein foodstuffs
is responsible for certain outbreaks and also for some of the phenomena
of food poisoning, the rapid development of symptoms being regarded as
due to the ingested poisons, whereas the later manifestations are
considered those of a true infection. Opposed to this view is the fact
that well-cooked food has proved distinctly less liable to cause food
poisoning than raw or imperfectly cooked food.

A large proportion of the recorded meat poisoning outbreaks are
significantly due to sausages made from raw meat and to meat pies,
puddings, and jellies. This is most likely because the heat used in
cooking such foods is insufficient to produce germicidal results. In
milk-borne epidemics also it is noteworthy that the users of raw milk
are the ones affected. For example, respecting an extensive _B.
enteritidis_ outbreak in and about Newcastle, England, it is stated:

  In no instance was a person who had used only boiled milk known to
  have been affected. Thus in one family, consisting of husband,
  wife, and wife's mother, the two women drank a small quantity of raw
  milk from the farm, at the most a tumblerful, and both were taken
  ill about twelve hours later. The husband, on the other hand,
  habitually drank a pint a day, but always boiled. He followed his
  usual custom on this occasion, and was unaffected.[76]

When in addition it is taken into consideration that the ordinary
roasting or broiling of a piece of meat is often not sufficient to
produce a germicidal temperature throughout, the argument that a
heat-resistant toxin is present in such cases is not conclusive. It must
be remembered also that in some outbreaks those persons consuming raw or
partly cooked meat have been affected while at the same time others
eating well-cooked meat from the same animal have remained exempt; this
would seem to indicate the destruction of living bacilli by heat, since
the toxic substances formed by these organisms are heat-resistant. The
view that a definite infection occurs, is favored, too, by the fact that
the blood-serum of affected persons so frequently has an agglutinative
action upon the paratyphoid bacillus. This would not be the case if the
symptoms were due to toxic substances alone. Altogether the rôle of
toxins formed by _B. enteritidis_ and its allies in food outside the
body cannot be said to be established. The available evidence points to
infection as the main, if not the sole, way in which the bacilli of this
group are harmful.

_Sources of infection._--The main sources of _enteritidis-suipestifer_
infection are: (1) diseased domestic animals, the infected flesh or milk
of which is used for food; (2) infection of food by human carriers
during the process of preparation or serving. To these may be added a
third possibility: (3) contamination of food with bacteria of this group
which are inhabitants of the normal animal intestine. Considering these
in order:

1. Diseased animals: The majority of the meat poisoning outbreaks are
caused by meat derived from pigs or cattle. Table III gives the figures
for a number of British[77] and German[78] epidemics.

TABLE III[79]

  ====================================================================
           |                    |                    |  BELONGING TO
           |   B. ENTERITIDIS   | B. SUIPESTIFER     | THIS GROUP BUT
           |                    |                    |UNDIFFERENTIATED
           |--------------------+--------------------+----------------
           |British|German|Total|British|German|Total|    British
  ---------+-------+------+-----+-------+------+-----+----------------
  Pig      |   1   |   1  |  2  |   3   |   5  |  8  |      4
  Ox or cow|   3   |   9  | 12  |   2   |   3  |  5  |      5
  Calf     |   0   |   7  |  7  |   2   |   2  |  4  |      0
  Horse    |   0   |   1  |  1  |   0   |   1  |  1  |     ...
  Chickens |   1   |   0  |  1  |   0   |   1  |  1  |     ...
  --------------------------------------------------------------------

Occasional outbreaks have also been attributed to infection through
eating rabbit, sheep, goose, fish, shrimp, and oysters. Especially
noteworthy is the relative rarity of infection from the meat of the
sheep.

More definite information is needed respecting the pathological
conditions caused by these bacteria in animals and the relation of such
conditions to subsequent human infection. A rather remarkable problem
is presented by the relation of _B. suipestifer_ to hog cholera. This
bacillus, although not now considered the causal agent of hog cholera,
is very commonly associated with the disease as an accessory or
secondary invader, and is frequently found in the internal organs of
swine after death. It might be supposed that in regions where hog
cholera is prevalent human infections would be more common than in
other districts, but this seems not to be the case. No connection
has ever been demonstrated between outbreaks of hog cholera--in which
_B. suipestifer_ is known to be abundantly distributed--and so-called
_B. suipestifer_ infections in man.

Suppurative processes in cattle, and especially in calves, have
given rise to poisoning from the use of the meat or milk of the
infected animals. It has been often demonstrated that bacteria of
the _enteritidis-suipestifer_ group are associated with inflammation
of the udder in cows and with a variety of septicemic conditions in
cattle and other domestic animals as well as with manifestations of
intestinal disturbances ("calf diarrhea," etc.).[80] The frequency
with which poisoning has occurred through the use of the meat of
"emergency-slaughtered" animals has been already mentioned. K. F.
Meyer[81] has reported an instance of accidental infection in a
laboratory worker caused by handling a bottle of sterilized milk
that had been artificially contaminated with a pure culture of
_B. enteritidis_ for experimental purposes. The strain responsible
for the infection had been isolated from the heart blood of a calf
that had succumbed to infectious diarrhea.

2. Human contamination: In a certain number of paratyphoid food
infections there is some evidence that the food was originally derived
from a healthy animal and became infected from human sources during the
process of preparation. In addition to the instances already mentioned
(Reinhold _et al._, p. 67) the Wareham (England, 1910) epidemic[82] was
considered by the investigators to be due to infection of meat pies by a
cook who was later proved to be a carrier of paratyphoid bacilli. The
evidence in this case, however, is not altogether conclusive.
Söderbaum[83] mentions a milk-borne paratyphoid epidemic occurring in
Kristiania which was ascribed to infection of the milk by a woman
milker. Sacquépée and Bellot[84] report an interesting paratyphoid
outbreak involving nineteen out of two hundred and fifty men in a
military corps. The patients fell ill on different dates between June 14
and June 21.

  It was found that an assistant cook who had been in the kitchen for
  several months had been attacked a little before the epidemic
  explosion by some slight malady which was not definitely diagnosed.
  He had been admitted to the hospital and was discharged
  convalescent. The cook, on being recalled and quarantined, stated
  that some days before June 10 he was indisposed with headache and
  anorexia. He had nevertheless continued his service in the
  kitchen.... _B. paratyphosus_ B (_B. suipestifer_) was repeatedly
  found in his stools in August, September, and October.... In all
  probability, therefore, the outbreak was due to food contaminated
  by a paratyphoid-carrier who had passed through an abortive attack
  of the fever.[85]

Bainbridge and Dudfield[86] describe an outbreak of acute
gastro-enteritis occurring in a boarding-house; it was found that no one
article of food had been eaten by all the persons affected, and there
were other reasons for supposing the outbreak to be due to miscellaneous
food contamination by a servant who was a carrier.

There is, therefore, ground for believing that occasional contamination
of food may be brought about by bacteria of this group derived from
human sources. It is not clear, however, how frequent this source of
infection is, compared to infection originating in diseased animals. It
must be admitted, too, that English investigators are disposed to look
upon outbreaks similar to those just described as infections with _B.
paratyphosus_ B, an organism which they would distinguish from the
"true" food poisoning bacilli, _B. enteritidis_ and _B. suipestifer_.

3. Miscellaneous contaminations: Some investigators, especially certain
German writers, regard the bacilli of the paratyphoid group as so widely
distributed in nature that any attempt to control the spread of
infection is like fighting windmills. According to this view the bacilli
occur commonly in our everyday surroundings and thence make their way
rather frequently into a variety of foodstuffs. Various German
investigators have reported the presence of paratyphoid bacilli in the
intestinal contents of apparently normal swine, cattle, rats, and mice
and more rarely of other animals, in water and ice, in German sausage
and chopped meat, and in the bodies of apparently healthy men. To what
extent their alleged ubiquity is due to mistaken bacterial
identification, as claimed by some English investigators, remains to be
proved. There is no doubt that in some quarters exaggerated notions have
prevailed respecting a wide distribution of the true paratyphoid
bacteria. Savage and others believe that the hypothesis that food
poisoning outbreaks are derived from ordinary fecal infection of food is
quite unfounded. It is pointed out that there is good evidence of the
frequent occurrence of intestinal bacteria in such food as sausages and
chopped meat, and that consequently, if paratyphoid infections could
occur through ordinary contamination with intestinal bacteria not
connected with any specific animal infection, food poisoning outbreaks
should be exceedingly common instead of--as is the case--comparatively
rare.

At the present time even those who maintain that these bacilli are of
common occurrence admit that their abundance is more marked in some
regions than in others. Southwest Germany, for example, seems to harbor
paratyphoid bacilli in relatively large numbers. Possibly local
differences in distribution may account for the discrepancies in the
published findings of German and British investigators.

A special case is presented by the relation of these bacilli to rats and
mice. Among the large number of bacteria of the paratyphoid group is the
so-called Danysz bacillus, an organism quite pathogenic for rodents, and
now and again used in various forms as a "rat virus" for purposes of
rodent extermination. Several outbreaks of food poisoning in man have
been attributed on more or less cogent evidence to food contamination
by one of these viruses either directly by accident, as in the case
described by Shibayama,[87] in which cakes prepared for rats were eaten
by men, or indirectly through food contaminated by mice or rats that had
been infected with the virus.[88] The use of such viruses has not proved
of very great practical value in the destruction of rodents, and is open
to serious sanitary objections, since the animals after apparent
recovery can continue to carry the bacilli of the virus and to
distribute them on or near food substances.

It seems possible that rats and mice may become infected with certain
bacteria of this group without human intervention, and that these
infected animals may be the means of contaminating foodstuffs and so
causing outbreaks of food poisoning. Proof of the frequency with which
this actually occurs is naturally difficult to obtain.

There is no escape from the conclusion that in any given case of food
poisoning the exact source of infection is often largely conjectural.
Even when suspicion falls strongly on a particular article of food, it
may not be possible to establish beyond a reasonable doubt whether the
material (meat or milk) came from a diseased animal or whether it was
infected from other sources (man or other animals) at some stage during
the process of preparation and serving. The most definitely attested
cases yet put on record are those in which it is possible to trace the
infection to food derived from an ailing animal.

_Means of prevention._--The most obvious and probably the most important
method of preventing infection with paratyphoid bacilli is the adoption
of a system of inspection which will exclude from the market as far as
possible material from infected animals. To be most effective such
inspection must be directed to examination of the living animal. The
milk or the meat from diseased animals may give no visible sign of
abnormality. In the Ghent outbreak of 1895 the slaughter-house
inspector, a veterinary surgeon, was so firmly convinced that the meat
which he had passed could have had no connection with the outbreak, that
he ate several pieces to demonstrate its wholesomeness. The experiment
had a tragic ending, as the inspector was shortly attacked with severe
choleraic symptoms and died five days later, paratyphoid bacilli being
found at the autopsy. Müller[89] also has described a case in which
paratyphoid bacilli were found in meat that had given rise to a meat
poisoning outbreak although the meat was normal in appearance and the
organs of the animal showed no evidence of disease to the naked eye. It
is evident that inspection of the live animal will often reveal evidence
of disease which might be missed in the ordinary examination of
slaughter-house products.

Although inspection of cows used for milking and of food animals before
slaughter is highly important, it does not constitute an absolute
protection. Emphasis must be repeatedly laid on the fact that meat, and
especially milk that is derived from seemingly healthy animals, may
nevertheless contain paratyphoid bacilli. To meet this difficulty in
part the direct bacterial examination of the carcasses of slaughtered
food animals has been proposed, but this seems hardly practicable as a
general measure. In spite of all precautions taken at the time of
slaughtering it seems probable that occasionally paratyphoid-infected
meat will pass the first line of defense and be placed on the market.

This danger, which is probably not a very grave one under a reasonably
good system of inspection of live animals, may be met by thoroughly
cooking all foods of animal origin. It is worth noting that some of the
internal organs, as the liver and kidneys, are more likely to contain
bacteria than the masses of muscle commonly eaten as "meat." Sausages,
from their composition and mode of preparation, and chopped meat
("hamburger steak") are also to be treated with especial care.
Consumption of such foods as raw sausage or diseased goose liver (paté
de foie gras) involves a relatively high risk. It is true of paratyphoid
infection as of most other forms of food poisoning that thorough cooking
of food greatly diminishes the likelihood of trouble.

Whatever be the precise degree of danger from food infection by healthy
paratyphoid-carriers (man or domestic animals), it is obvious that
general measures of care and cleanliness will be more or less of a
safeguard. As with typhoid fever so all outbreaks of paratyphoid should
be thoroughly investigated in order that the sources of infection may be
found and eliminated. The possible connection of rats and mice with
these outbreaks should furnish an additional incentive to lessen the
number of such vermin as well as to adopt measures of protecting food
against their visits.


FOOTNOTES:

[62] _Fleischvergiftungen u. Paratyphusinfektionen_ (Jena, 1910).

[63] _Rept. to Local Govt. Board_, N.S. No. 77 (London, 1913).

[64] _Zeit. f. Hyg._, XXII (1896), 53.

[65] _Brit. Med. Jour._, I (1909), 1171.

[66] Bernstein and Fish, _Jour. Amer. Med. Assoc._, LXVI (1916), 167.

[67] _Breslau aerztl. Ztschr._, X (1888), 249.

[68] Bernstein and Fish, _Jour. Amer. Med. Assoc._, LXVI (1916), 167.

[69] _Deutsche Viertelj. f. öffentl. Ges._, XLV (1913), 58-59.

[70] _Op. cit._, pp. 60-62.

[71] _Jour. Infect. Dis._, XX (1917), 457.

[72] _Centralbl. f. Bakt._, I Orig., LIII (1910), 377.

[73] _Cor.-Bl. f. schweiz. Aerzte_, XLII (1912), 281 and 332.

[74] _Jour. Hyg._, XII (1912), 1.

[75] See Sobernheim and Seligmann, _Centralbl. f. Bakt._, Ref., Beilage,
L (1911), 134.

[76] _Report Med. Officer of Health_ (Newcastle-upon-Tyne, 1913).

[77] Compiled from Savage, _Report of Local Gov't Board_, 1913.

[78] Mayer, _Deutsche Viertelj. f. öffentl. Ges._, XLV (1913), 8.

[79] It must be noted that origin of the food from a diseased animal was
not definitely proved in all the cases cited. Some of these cases should
possibly be classed under human contamination (2).

[80] Although not directly connected with the question of food
poisoning, it is of interest to note that certain diseases of birds have
been traced to infection with members of this group of bacteria. In a
few cases, as in several epidemics among parrots in Paris and elsewhere,
the infection has been communicated to man by contact.

[81] _Jour. Infect. Dis._, XIX (1916), 700.

[82] R. Trommsdorff, L. Rajchman, and A. E. Porter, _Jour. Hyg._, XI
(1911), 89.

[83] _Hygiea_, LXXV (1913), 1.

[84] _Progrès méd._, 3d series, XXVI (1910), 25.

[85] Ledingham and Arkwright, _The Carrier Problem in Infectious
Diseases_, pp. 152-53.

[86] _Jour. Hyg._, XI (1911), 24.

[87] _Münch. med. Wchnschr._, LIV (1907), 979.

[88] See, for example, H. Langer and Thomann, _Deutsche med. Wchnschr._,
XL (1914), 493.

[89] _Ztschr. f. Infektionsk. ... d. Haustiere_, VIII (1910), 237.



CHAPTER VII

ANIMAL PARASITES


Not only pathogenic bacteria but certain kinds of animal parasites
sometimes enter the human body in or upon articles of food. One of the
most important of these is the parasite causing trichiniasis.


TRICHINIASIS

Trichiniasis or trichinosis is a disease characterized by fever,
muscular pains, an enormous increase in the eosinophil blood corpuscles,
and other more or less well-defined symptoms; at the onset it is
sometimes mistaken by physicians for typhoid fever. The responsible
parasite is a roundworm (_Trichinella spiralis_, formerly known as
_Trichina_) which is swallowed while in its encysted larval stage in raw
or imperfectly cooked pork.[90] The cysts or envelopes in which the
parasites live are dissolved by the digestive fluids and the young
larvae which are liberated develop in the small intestine to the adult
worm, usually within two days. The young embryos, which are produced in
great numbers by the mature worms, gain entrance to the lymph channels
and blood stream, and after about ten days begin to invade the
muscles--a procedure which gives rise to many of the most characteristic
symptoms of the infection. It is estimated that in severe cases as many
as fifty million embryos may enter the circulation. The parasites
finally quiet down and become encysted in the muscle tissue and the
symptoms, as a rule, gradually subside. Ingestion of a large number of
parasites at one time often results fatally, the mortality from
trichiniasis being on the average somewhat over 5 per cent and rising in
some outbreaks to a much higher figure (30 per cent). On the other hand,
many infections are so light as to pass unnoticed. Williams[91] found
_Trichinella_ embryos present in 5.4 per cent of the bodies of persons
dying from other causes. Such findings are considered to indicate that
occasional slight _Trichinella_ infections even in the United States are
quite common. This might indeed be expected from the frequent occurrence
of infection in swine, about 6 per cent of these animals being found to
harbor the parasite.

[Illustration: FIG. 7.--Trichinae encysted in intercostal muscle of pig.
(About 35×1.) (After Neumann and Mayer.)]

The specific symptoms (such as the muscular pain) of trichiniasis may be
due in part to mechanical damage of the muscle tissue, but it is also
probable that they are partly due to toxic products exuded by the worms
and partly to the introduction of alien protein material--the protein of
the worm--into the tissues. Secondary bacterial infection is also a
possibility, but there is little evidence to prove that this is an
important factor in most cases of trichiniasis. The various stages
observed in the progress of the disease are plainly connected with the
different phases of the worm's development--the initial localization in
the intestines, the invasion of the muscles, and the final encystment.

Swine become infected with this parasite by eating scraps of infected
meat, or the offal of their own kind, or by eating infected rats. The
rat, through its cannibalistic propensities, becomes infected
frequently, and is one of the chief factors in the wide dissemination of
the disease. Human infection is practically accidental and self-limited;
biologically speaking, man as a host does not enter into the
calculations of the parasite.

Treatment of established trichiniasis infection is palliative, not truly
remedial. The parasites, once inside the body, cannot be materially
affected by the administration of any drug. While cure of trichiniasis
is thus difficult, if not impossible, prevention is very simple. The
thorough cooking of all food is sufficient to preclude infection. This
relatively simple means of destroying the larvae is a more certain as
well as less expensive method of preventing infection than is the
laborious microscopic examination of the tissues of every slaughtered
hog. In Germany between 1881 and 1898 over 32 per cent of 6,329 cases of
trichinosis that were investigated were traced to meat that had been
microscopically examined and passed as free from trichinae.[92] On the
other hand, thorough cooking removes all possibility of danger.


TENIASIS

Various tapeworm or cestode infections are contracted by eating meat
containing the parasite. Particular species of tapeworm usually infest
the flesh of specific hosts, as _Tenia saginata_ in the beef and _Tenia
solium_ in the hog. The dwarf tapeworm, _Hymenolepis nana_, develops in
rats, and the human infections with this parasite occasionally observed
are probably caused by contamination of food by these animals.

[Illustration: FIG. 8.--_Cysticercus cellulosae_ in pig's tongue. (After
Neumann and Mayer.)]

Sometimes the existence of the tapeworm in man is restricted to the
alimentary tract and the symptoms vary from trivial to severe, but
sometimes (_Tenia solium_) the larval stage of the tapeworm invades the
tissues and becomes encysted in various organs (brain, eye, etc.),
where, as in the case of cerebral infection, it may result fatally. The
encysted larva of _Tenia solium_ was at one time regarded as an
independent animal species and named _Cysticercus cellulosae_. The
condition known as "measly pork" is produced by the occurrence of this
encysted parasite.

So-called hydatid disease is due to the cystic growth produced by the
larva of a species of tapeworm (_Echinococcus_) inhabiting the intestine
of the dog. Human infection may be caused by contaminated food as well
as more directly by hands soiled with petting infected dogs. Several
varieties of tapeworms infesting fish, especially certain fresh-water
species, may be introduced into the human body in raw or partly cooked
fish.

Methods for the prevention of tapeworm infection include the destruction
of the larvae by heat--that is, the thorough cooking of all meat and
fish--and the minimization of close contact with those animals, such as
the dog and cat, that are likely to harbor parasites. Cleanliness in the
preparation and serving of food, and attention to hand-washing before
meals, and especially after touching pet animals, are necessary
corollaries.


UNCINARIASIS

Hookworm infection (uncinariasis, ankylostomiasis) is commonly caused by
infection through the skin of the feet, but the possibility of mouth
infection cannot be disregarded, and in regions where hookworm disease
exists methods of guarding against food contamination should be
practiced, as well as other precautions. Billings and Hickey[93] believe
that hookworm disease is contracted by unconscious coprophagy (from raw
vegetables) much more frequently than is generally supposed.


OTHER PARASITES

A number of other parasitic worms (e.g., _Strongyloides_, _Ascaris_ or
eelworm, and _Oxyuria_ or pinworm) may conceivably enter the human body
in contaminated food, and while, as in hookworm disease, other modes of
infection are probably more important, the liability to occasional
infection by uncooked food must not be overlooked.

[Illustration: FIG. 9.--_Lamblia intestinalis._ (After Neumann and
Mayer.)]

Various forms of dysentery or diarrhea have been attributed to infection
with _Giardia (Lamblia) intestinalis_. Observations made by Fantham and
Porter[94] upon cases contracted in Gallipoli and Flanders have given
support to this view. Strains of this parasite of human origin have been
shown to be pathogenic for mice and kittens. It is considered possible
that these animals may act as reservoirs of infection and spread the
disease by contamination of human food.


FOOTNOTES:

[90] The consumption of raw sausage made with pig meat is particularly
likely to give rise to trichiniasis.

[91] _Jour. Med. Research_, VI (1901), 64.

[92] Edelmann, Mohler, and Eichhorn, _Meat Hygiene_, 1916, p. 182.

[93] _Jour. Amer. Med. Assoc._, LXVII (1916), 1908.

[94] _Brit. Med. Jour._, II (1916), 139.



CHAPTER VIII

POISONOUS PRODUCTS FORMED IN FOOD BY BACTERIA AND OTHER MICRO-ORGANISMS


In close relation to the cases of infection with animal or plant
parasites which have been discussed, there are certain well-established
instances of poisoning by substances that have been generated in food
while it is still outside of the body. This is the common type of food
poisoning in popular estimation, but in point of fact the proved cases
of this class are much less frequent than the instances of true
infection with bacteria of the _paratyphoid-enteritidis_ group (chapter
vi). Thus far the best-known examples of poisoning by the products of
micro-organisms are botulism and ergotism.


ERGOTISM

Ergotism or ergot poisoning is due to the use of rye that has become
diseased through the attack of a fungus, _Claviceps purpurea_. It
occurred frequently in the Middle Ages when in times of famine the ergot
or spurred rye (O.Fr. _argot_, "a cock's spur") was often used in
default of better food. In Limoges in 922 it is said that forty thousand
persons perished from this cause. Improvement in the facilities for
transportation of food into regions where crops have failed, and the use
of special methods for separating the diseased grain from the wholesome
have greatly reduced the prevalence of ergotism. In Western Europe
poisoning from this cause has practically ceased, although Hirsch
recorded some twenty-eight outbreaks in the nineteenth century; in
parts of Russia the disease is said still to occur in years of bad
harvest.[95]

The poison ergot itself has long been used as a drug in obstetrics, but
its composition is complex and is still not completely understood.
Several constituents of ergot have been extracted, and these have been
shown to possess different physiological effects.[96] The symptoms
observed in the outbreaks of ergotism of mediaeval times are not wholly
reproduced experimentally by the drug and are thought to have been in
part due to the semi-starvation engendered by the use of rye from which
the nutritious portions had been largely removed by the growth of the
fungus.


BOTULISM

The best established case of poisoning by means of bacterial products
taken in with the food is the serious malady known somewhat
inappropriately as botulism (botulus, sausage).[97] This kind of food
poisoning, which has a characteristic set of symptoms, seems to have
been first recognized and described in 1820 by the German poet and
medical writer Justinus Kerner. In two articles (1820-22) he enumerates
174 cases with 71 deaths occurring in Württemberg between 1793 and 1822
and apparently in most cases connected with the use of insufficiently
smoked sausage. Mayer[98] tabulates about 600 additional cases observed
in various parts of Germany down to the end of 1908, the total mortality
in the 800 cases being about 25 per cent. In France botulism is said to
be very rare.[99] In Great Britain Savage[100] declares that he has been
unable to trace the occurrence of a single outbreak. In the United
States several instances of botulism poisoning are on record
(Sheppard,[101] 1907, 3 cases, 3 deaths, canned pork and beans;
Peck,[102] 1910, 12 cases, 11 deaths; Wilbur and Ophüls,[103] 1914,
canned string beans, 12 cases, 1 death; Frost,[104] 1915, 3 cases, 3
deaths). Professor Stiles[105] has given a graphic description of his
own attack of probable botulism due in all likelihood to minced chicken.

[Illustration: FIG. 10.--_Claviceps purpurea:_ 1, ergot on rye-grass; 2,
ergot on rye; 3, section of a portion of the conidial form of fruit,
×300; 4, a sclerotium or ergot; 5, head of ascigerous form of fruit; 6,
an ascus, ×300; 7, a single spore, ×300. (After Massee, _Plant
Diseases_, by courtesy of the Macmillan Company.)]

_Symptoms._--The description of a case seen by Wilbur and Ophüls,[106]
is so typical that it may be cited:

  Girl, aged 23, Tuesday evening, Nov. 23, 1913, ate the dinner
  including the canned string beans of the light green color together
  with a little rare roast beef. The following day she felt perfectly
  normal except that at 10:00 in the evening the eyes felt strained
  after some sewing. Thursday morning, thirty-six hours after the
  meal, when the patient awoke, the eyes were out of focus, appetite
  was not good, and she felt very tired. At night she had still no
  appetite, was nauseated, and vomited the noon meal apparently
  undigested. Friday morning, two and one-half days after the meal,
  the eyes were worse, objects being seen double on quick movement,
  and it was noticed that they had a tendency to be crossed. A
  peculiar mistiness of vision was also complained of. She was in bed
  until late in the afternoon, when she visited Dr. Black. She had had
  some disturbance in swallowing previous to this time and stated that
  it felt as if "something came up from below" that interfered with
  deglutition. The fourth day she remained in bed, was much
  constipated, and noticed a marked decrease in the amount of urine
  voided. There was at no time pain except for occasional mild
  abdominal cramps, no headache, subnormal temperature, and a normal
  pulse. The fourth and fifth days the breathing became difficult at
  times and swallowing was almost impossible. The patient complained
  of a dry throat with annoying thirst. The sixth day there were
  periods of a sense of suffocation with a vague feeling of unrest and
  as if there might be difficulty in getting the next breath. The
  upper lids had begun to droop. The voice was nasal. When the attempt
  was made to swallow liquids they passed back through the nose. The
  patient felt markedly weak.

  Physical examination at this time showed ptosis of both upper
  eyelids, dilatation of the right pupil, sluggish reaction to light
  of both pupils, apparent paralysis of the internal rectus of the
  left eye, normal retina, inability to raise the head, control
  apparently having been lost of the muscles of the neck, inability to
  swallow, absence of taste. The tongue was heavily coated and the
  throat was covered with a viscid whitish mucus clinging to the
  mucous membrane. The soft palate could be raised but was sluggish,
  particularly on the right side. The exudate on the right tonsil was
  so marked that it resembled somewhat a diphtheritic membrane. The
  seventh day there was some change in the condition; occasional
  periods occurred when swallowing was more effective, and there was
  less tendency to strangle. On the eleventh day there was some
  improvement of the eyes, still strangling on swallowing, sensation
  of taste was keener, and the general condition improved. The twelfth
  day the patient was able to move her head, but was unable to lift it
  except when she took hold of the braids of her hair, and pulled the
  head forward. The eyes could be opened slightly, speech was less
  nasal and more distinct, and improvement in swallowing was marked.
  At the end of two weeks the patient was able to take soft diet
  freely, and at four weeks she was up in a chair for a couple of
  hours complaining only of general weakness and inability to use her
  eyes. At the end of five weeks she was able to leave the hospital
  and return to her home and later to resume her regular work.

In all cases the nervous system is strikingly affected in this form of
food poisoning. Dizziness, double vision, difficulty in chewing and
swallowing, and other symptoms of nervous involvement occur with varying
intensity and may persist for a long time after the first signs of the
attack. Temperature, pulse, and respiration remain practically normal.
In contrast with the traditional type of food poisoning
gastro-intestinal symptoms may be slight or altogether lacking. Freedom
from abdominal pain is usually noted; diarrhea is the exception and
constipation the rule; vomiting sometimes occurs, but may be absent. In
the cases described by Sheppard there was "an entire absence of the
usual gastro-intestinal symptoms from first to last, no pain or sensory
disturbance and no elevation of temperature." The visual disturbances
are very characteristic. Stiles relates his own experiences as follows:

  Vertigo and nystagmus developed [a few hours after eating] in a
  startling degree, the car [in which he was being taken to his house]
  seemed to be ascending an endless spiral, the stars made circles in
  the sky, and the houses by the wayside reeled. The lighted doorway
  of my house seemed to approach and surround me as I was carried in.
  My bed for the moment presented itself as a vertical surface which I
  could not conceive to be a resting place.... Whenever I opened my
  eyes on this day [the next day] the impression of gyration of the
  room was appalling.... To turn my head even very slowly from one
  side to the other brought an accession of the overpowering
  giddiness.... [eight days after the beginning of the attack]. The
  nystagmus now became limited to momentary onsets, but in its place I
  became aware of a peculiar diplopia. The image of one retina was not
  merely displaced from the position of its fellow but was tilted
  about 15 degrees from parallel.... This fantastic diplopia gradually
  gave place to the familiar variety and this occurred less and less
  often as my convalescence proceeded. From [this date] my recovery
  pursued a course which was dishearteningly slow but free from any
  setbacks. Among the persistent symptoms were ... the visual
  difficulties mentioned. The left pupil was usually smaller than the
  right and I thought I detected a slight failure to relax
  accommodation with the left eye. Reading was difficult for several
  weeks and the ability to write, as requiring closer fixation, was
  still longer in returning.

In the cases reported by Sheppard visual symptoms were the initial signs
of trouble, double vision, mistiness, and inability to hit the mark in
shooting being the first complaint.

The time elapsing between eating the implicated food and the onset of
the earliest symptoms is usually between twelve and forty-eight hours,
but may be much less. In Stiles's case the interval was apparently less
than three hours.

_Anatomical lesions._--In fatal cases no characteristic gross changes
are observed in the various organs. It has been stated by some writers
that microscopic degenerative changes occur in the ganglion cells,
involving especially the so-called Nissl granules, but in the carefully
studied case reported by Ophüls[107] the Nissl granules were quite
normal in size, arrangement, and staining qualities. There was, in fact,
no evidence to substantiate the hypothesis of a specific action of the
toxin on the nerve-cells. On the other hand, Ophüls found numerous
hemorrhages in the brain-stem and multiple thromboses in both the
arteries and veins. He holds, consequently, that the indications of
severe disturbances of brain circulation associated with hemorrhages and
thrombosis in medulla and pons are sufficient to explain the symptoms of
botulism poisoning without having recourse to the assumption that the
poison has a specific action on certain ganglion cells.

_Bacteriology._--The cause of botulism poisoning was discovered by Van
Ermengem to be the toxin produced by a bacillus which he named _B.
botulinus_. This organism was isolated from portions of a ham that had
caused fifty cases of poisoning (1895) at Ellezelles (Belgium), and also
from the spleen and gastric contents of one of the three fatal cases.
The bacillus grows only in the absence of oxygen (strict anaërobe),
stains by Gram's method, forms terminal spores, and develops best at
22°C. Unlike most bacteria dangerous to man, it appears unable to grow
in the human body, and its injurious effect is limited to the action of
the toxin produced in foodstuffs outside the body. Botulism is an
intoxication--not an infection. The fact that the bacillus can grow in
nature only when the free oxygen supply is cut off explains in part at
least the relatively rare occurrence of botulism since all the
conditions necessary for the production of the botulism toxin do not
commonly concur. Next to nothing is known as to how widely _B.
botulinus_ is distributed. Except in connection with the cases of
poisoning it has been reported but once in nature.[108] The botulism
poison is a true bacterial toxin, chemically unstable, destroyed by
heating at 80°C. for 30 minutes, capable of provoking violent symptoms
in minute doses, and possessing the property characteristic of all true
toxins of generating an antitoxin when injected in small, non-fatal
doses into the bodies of susceptible animals. In animal experiments the
toxin formed by _B. botulinus_ has been found capable of reproducing the
typical clinical picture of this form of food poisoning. Symptoms of
paralysis are produced in rabbits, guinea-pigs, and other animals by the
injection of so small a dose as 0.0001 c.c. of a filtered broth culture.

[Illustration: FIG. 11.--_Bacillus botulinus_ with spores. Pure culture
on sugar-gelatin. Van Ermengem preparation. (Kolle and Wassermann.)]

_Epidemiology._--The conditions under which _B. botulinus_ occurs and is
given opportunities for multiplying are not completely known. It is
possible that there are localities where this bacillus is particularly
abundant in the soil or in the intestinal contents of swine or other
domestic animals, but on the whole it seems more probable that the
organism is widely distributed, but that it does not often find suitable
conditions for entrance into, and multiplication in, human food.
Practically all the reported cases of botulism have been caused by food
which has been given some sort of preliminary treatment, as smoking,
pickling, or canning, then allowed to stand for a time, and _eaten
before cooking_. Since both the bacillus, including the spore stage, and
its toxin are destroyed by relatively slight heating, it is clear that a
rather unusual set of factors must co-operate in order that botulism
poisoning shall take place. These are evidently: (1) the presence of the
bacilli in sufficient numbers in a suitable foodstuff; (2) the initial
preparation of the food by a method that does not destroy the _B.
botulinus_--inadequate smoking, too weak brine,[109] or insufficient
cooking; (3) the holding of this inadequately preserved food for a
sufficient length of time under the right conditions of temperature and
lack of oxygen; (4) the use of this food, in which conditions have
conspired to favor the production of toxin by _B. botulinus_, without
final adequate cooking. It seems as reasonable to suppose that the
infrequency with which these several factors coincide is responsible for
the relative uncommonness of botulism as to suppose it due to the rarity
of the specific bacillus. In the Belgian outbreak studied by Van
Ermengem the poisonous ham had lain at the bottom of a cask of brine
(anaërobic conditions) while the other ham of the same animal lay on top
of it but was not covered with brine, and was eaten without producing
any poisonous effect. In this instance the presence or absence of
favorable conditions for anaërobic growth seemed to be the decisive
factor.

_Prevention and treatment._--The food in which _B. botulinus_ has grown
does not seem to be altered in a way that necessarily arouses
suspicion. In the case described by Römer the incriminated ham showed
bluish-gray areas from which _B. botulinus_ could be isolated, but this
condition does not seem to have attracted attention before the poisoning
occurred and was an observation made only after the event. So far as can
be learned the meat that has caused botulism has always come from
perfectly sound animals. In some cases the accused article of food is
said to have had a rancid or acrid taste (due to butyric acid?), but
there is nothing definitely characteristic about this, as the majority
of anaërobes produce butyric acid. If, as in the Darmstadt[110] and
Stanford University[111] epidemics, the food (canned beans) is served
with salad dressing, a sour taste might pass without notice or even add
to the relish. In the instance reported by Sheppard the canned beans
were good in appearance, taste, and smell.

The obvious precaution to take against poisoning of this sort is first
the use of adequate methods of food preservation. To judge from the
recorded outbreaks, domestically prepared vegetables and meats are more
likely to give rise to botulism than those prepared commercially on a
large scale. The general use of steam under pressure in the large
canning factories affords a high degree of protection against the
anaërobic bacteria and their resistant spores. Whatever the method of
treatment, all canned or preserved food having an unnatural appearance,
taste, or odor should be rejected. Reheating of all prepared foods
immediately before use is an additional safeguard. Foods, such as
salads, composed wholly or in part of uncooked materials should not be
allowed to stand overnight before being served.

If symptoms of botulism, such as visual disturbances, become manifest,
the stomach should be emptied with a stomach pump, cathartics
administered, and strychnine and other stimulants given as required.
Since one of the noteworthy features of this disease is the paralysis of
the intestinal tract by the toxin absorbed, the guilty food may lie for
a long time in the stomach (cf. Stiles, _loc. cit._). Consequently,
measures to empty the stomach should be taken even if the patient does
not come under observation until several days after the poisonous food
has been eaten.

An antitoxic serum has been prepared at the Koch Institute in Berlin.
This serum has given successful results in animal experimentation, but
has not been used, so far as I can learn, in any human outbreak. It is
not available at any point in this country.


OTHER BACTERIAL POISONS

The interesting case reported by Barber[112] shows that there are other
possibilities of food poisoning by formed bacterial poisons. Acute
attacks of gastro-enteritis were produced in several individuals by the
use of milk containing a poisonous substance elaborated by a white
staphylococcus. This staphylococcus occurred in almost pure culture in
the udder of the cow from which the milk was derived. The milk when used
fresh was harmless and the poison was generated in effective quantities
only when the milk stood some hours at room temperature before being
used. The symptoms were similar to those usually ascribed to "ptomain
poisoning."


SPOILED AND DECOMPOSED FOOD

There is a general belief that food is unwholesome whenever the evidence
of the senses shows it to be more or less decomposed. This opinion finds
expression in civilized countries in many legal enactments forbidding
traffic in decomposed meats, vegetables, and fruits. There is
unfortunately lack of evidence as to what kinds or degree of visible
decomposition are most dangerous. In fact, some foods of high nutrient
value, notably cheeses, are eaten only after somewhat extensive
decomposition processes (termed ripening) have taken place. The
characteristic flavors or aromas of the various hard and soft cheeses
are due to the substances formed by certain species of molds and
bacteria and are just as properly to be regarded as decomposition
products as the unpleasant stenches generated by decomposing eggs or
meat. Indeed, some of the decomposition products formed in the ripening
of Brie, Camembert, or Limburger are similar to, if not identical with,
those which are associated with spoiled foods. Sour milk, again, is
recommended and commonly used as a food or beverage for persons in
delicate health, and yet sour milk contains many millions of bacteria
and their decomposition products. Some of the bacteria commonly
concerned in the natural souring of milk are closely related to
pathogenic types. The partial decomposition of meats and game birds is
often considered to be advantageous rather than otherwise. Even eggs, a
food whose "freshness" is marred for most persons by the initial stages
of decomposition, are ripened in various ways by the Chinese and eaten
as a delicacy after the lapse of months or years. The preserved ducks'
eggs known as pidan are stored for months in a pasty mixture of tea,
lime, salt, and wood ashes. "They are very different from fresh eggs.
The somewhat darkened shell has numerous dark green dots on the inner
membrane. Both the white and yolk are coagulated; the white is brown,
more or less like coffee jelly...."[113] Increase of ammoniacal nitrogen
has taken place to an extraordinary degree in these eggs, indicating
much decomposition of the egg protein. The ammoniacal nitrogen in pidan
is considerably higher than in the eggs known by egg candlers as black
rots.

It is evident, therefore, that bacterial growth in substances used as
food is not necessarily injurious and may in some cases increase the
palatability of food without destroying its wholesomeness. Little or
nothing is known about the correlation of visible signs of decomposition
with the presence of poisonous products, and it is at present impossible
to say at what point in the process of decomposition a food becomes
unfit to use owing to the accumulation of poisonous substances within
it. There seems to be no connection between the natural repugnance to
the use of a food and its unwholesomeness. Under ordinary conditions the
nauseous character of very stale eggs is proverbial, and yet few
nitrogenous foods have so clear a health record as eggs or have been so
infrequently connected with food poisoning outbreaks.

It might seem tempting to conclude on the basis of the available
evidence that spoiled or decomposed foods possess poisonous qualities
only when certain specific bacteria, like the _B. botulinus_ already
discussed, have accidentally invaded them and formed definite and
specific poisons. But we have no right to assume that the everyday
decomposition products of the banal bacteria are in all cases without
injurious effects. Even though no sharply defined acute form of
poisoning may be laid at their door, it does not follow that an
irritating or perhaps slightly toxic action of the ordinary
decomposition products is altogether absent. Our present knowledge of
the nature and degree of danger to be apprehended from the use of
spoiled food is imperfect and unsatisfactory. That fact, however, does
not release us from the obligation to continue measures of protection
based even to a limited extent on experience.


FOOTNOTES:

[95] Another species of _Claviceps_ (_C. paspali_) which attacks the
seeds of a wild grass is believed to be responsible for certain
outbreaks of poisoning among cattle and horses (_Science_, XLIII [1916],
894).

[96] Barger (_Jour. Chem. Soc._, XCV [1909], 1123) has shown that
parahydroxyphenylethylamine is present in ergot and is in some degree
responsible for the physiological action of the drug.

[97] Although some of the early outbreaks were traced to the use of
sausage, particularly in Württemberg, the proportion of recent botulism
poisoning attributed to this food is no greater than of sausage-conveyed
infections with the paratyphoid bacillus (chap. vi), and a number of the
most completely studied outbreaks of botulism have been traced to ham,
beans, and other foods.

[98] _Deutsche Viertelj. f. öffentl. Ges._, XLV (1913), 8.

[99] E. Sacquépée, _Progrès méd._, XXVI (1910), 583.

[100] _Report to Local Govt. Board on Bacterial Food Poisoning and Food
Inspection_, N.S. No. 77, 1913, p. 27.

[101] _Southern Cal. Pract._, XXII (1907), 370.

[102] _Ibid._, XXV (1910), 121.

[103] _Arch. of Int. Med._, XIV (1914), 589.

[104] _Amer. Med._, X (1915), 85.

[105] _Jour. Amer. Med. Assoc._, LXI (1913), 2301.

[106] _Loc. cit._

[107] _Loc. cit._

[108] In the feces of a healthy pig (Kempner and Pollock, _Deutsche med.
Wchnschr._, XXIII [1897], 505).

[109] _B. botulinus_ does not develop in media containing over 6 per
cent of salt and should not be able to grow in meat properly covered in
brine made with 10 per cent of salt (Römer, _Centralbl. f. Bakt._, XXVII
[1900], 857).

[110] G. Landmann, _Hyg. Rundschau_, XIV (1904), 449.

[111] Wilbur and Ophüls, _Arch. of Int. Med._, XIV (1914), 589.

[112] _Phil. Jour. of Science_, IX (1914), B6, p. 515.

[113] K. Blunt and C. C. Wang, _Jour. Biol. Chem._, XXVIII (1916), 125.



CHAPTER IX

POISONING OF OBSCURE OR UNKNOWN NATURE


While many and diverse causes of food poisoning have been discussed in
the foregoing pages, there remain certain affections definitely
connected with food that are still of obscure or doubtful causation.


MILKSICKNESS OR TREMBLES

This disease, common to man and some of the higher animals, is
characterized by a definite symptom-complex, the salient features being
excessive vomiting and obstinate constipation accompanied usually by a
subnormal temperature. Many cases result fatally. At the present time it
is known to occur only rarely in some of the southern and central
western states in this country, but during the period of pioneer
settlement it was quite common in districts that are now seldom
affected. A great many references to milksickness are found in the
writings of the early travelers and physicians in the Middle West, one
observer predicting that "some of the fairest portions of the West in
consequence of the prevalence of this loathsome disease must ever remain
an uninhabitable waste unless the cause and remedy can be discovered."
In certain regions it is estimated that "nearly one-fourth of the
pioneers and early settlers died of this disease." The mother of Abraham
Lincoln fell a victim to this malady in 1818 in southern Indiana.

The disease appears to be usually contracted in the first instance by
grazing cattle or sheep that have access to particular tracts of land;
"milksickness" pastures are, as a rule, well known locally for their
dangerous qualities. Milksickness is communicated to man through the
medium of raw milk, or butter and possibly of meat. Although some of the
earlier observers make the statement that the disease is
self-propagating and can be passed on without limit from one animal to
another, later experiments cast doubt on this view.[114]

Many different theories have been advanced to account for the origin of
the disease. The belief that mineral poisons such as arsenic or copper
might be taken up by grazing animals and eliminated in the milk finds no
justification either in analytical or in clinical data. Many plants,
known or suspected to be poisonous, have been accused of furnishing the
substance that imparts the poisonous quality to the milk of animals
suffering from trembles, but there is no agreement as to the responsible
species. Feeding experiments with suspected plants have in no case given
unambiguous results. While some facts have been supposed to indicate
that living micro-organisms are the cause of milksickness, other facts
are opposed to this view, and the most recent experiments in this
direction did not lead to conclusive results.[115] The true cause of
milksickness is at present quite unknown.


DEFICIENCY DISEASES

Although diseased conditions due to the absence rather than the presence
of certain constituents in the food are not perhaps to be properly
classed as food poisoning, they may be mentioned here to illustrate the
complexity of the food problem. At least one disease,--pellagra--is
attributed by some observers to the presence of an injurious substance
or micro-organism in the food, and by others to the absence of certain
ingredients necessary to the proper maintenance of life.

_Beriberi._--One of the best established instances of a disease due to a
one-sided or defective diet is beriberi. This affection is prevalent
among those peoples subsisting chiefly or wholly on a diet of rice
prepared in a certain way. As a matter of trade convention milled white
rice has long been considered superior to the unpolished grain. The
process of polishing rice by machinery removes the red husk or pericarp
of the grain, and a diet based almost exclusively on polished rice
causes this well-marked disease--beriberi--which was for long regarded
as of an infectious nature.[116] It has been shown that if the husks are
restored to the polished grain and the mixture used as food the disease
fails to develop. Experiments upon chickens and pigeons show that an
exclusive diet of white rice causes in these animals a disease
(polyneuritis of fowls) similar to beriberi, which likewise can be
arrested or prevented by a change in diet. From such observations the
conclusion has been drawn that in the pericarp of the rice grain there
are certain substances essential to the maintenance of health and that
their withdrawal from the diet leads to nutritional disturbances. The
name "vitamin" has been given to these substances, but little is known
about their chemical or physiological nature. In a varied diet vitamins
are presumably present in a variety of foodstuffs, but if the diet is
greatly restricted, some apparently trivial treatment of the food may
result in their elimination. It is uncertain how many and how various
the substances are that have been classed by some writers under the
designation vitamin. At least two "determinants" are thought to be
concerned in the nutrition of growth, a fat-soluble and a water-soluble
substance.[117]

_Pellagra_ is one of the diseases attributed to an unbalanced diet,[118]
and it has been suggested that the increased use of highly milled maize
and wheat flour from which vitamins are absent may be responsible for
the extension of this malady in recent years. Other observers, while
admitting that a faulty diet may predispose to pellagra as to
tuberculosis and other diseases, do not assent to the view that it is
the primary factor.[119]

_Lathyrism._--The name lathyrism has been given to a disease supposed to
be connected with the use of the pulse and the chick pea. Nervous
symptoms are conspicuous and sometimes severe, although the affection is
of a milder type than pellagra. The disease is said to be associated
with the exclusive or almost exclusive use of leguminous food and with
generally miserable conditions of living. It is yet uncertain whether
lathyrism is a deficiency disease like beriberi and possibly pellagra,
or whether it is due to a mixture of foreign and poisonous seeds with
the particular legumes consumed, or whether under certain conditions
the legumes themselves may contain poisonous substances generated by
some unknown fungus growths.

_Favism_ (from _fava_, "bean") is an acute febrile anemia with jaundice
and hemoglobinuria which occurs in Italy and has been attributed to the
use of beans as food or even to smelling the blossom of the bean
plant.[120] A marked individual predisposition to the malady is said to
exist. Although the symptoms are very severe and seem to point to an
acute poisoning, no toxic substance has been isolated from the
implicated beans. It has been suggested by some that bacterial
infection, and by others that a fungous growth on the bean, is
responsible, but no evidence has been brought forward to support either
assumption.

_Scurvy_ in some forms is undoubtedly connected with the lack of certain
necessary components of a normal diet. The development of scurvy on
shipboard in the absence of fresh milk, fresh vegetables, fruit juice,
and the like is a fact long familiar. Guinea-pigs fed on milk, raw and
heated, and on milk and grain have developed typical symptoms of
scurvy.[121] On the other hand, a form of experimental scurvy has been
produced in guinea-pigs and rabbits kept on an ordinary diet of green
vegetables, hay, and oats by the intravenous injection of certain
streptococci.[122] The relative share of diet and infection in the
production of human scurvy is consequently regarded by some
investigators as uncertain.

_Rachitis_ or rickets is a pathological condition in some way connected
with a protracted disturbance of digestion which in turn leads to faulty
calcium metabolism. It does not seem probable that rickets is caused by
too little calcium in the food, but rather by the inability of the bone
tissue to utilize the calcium brought to it in the body fluids.
Experiments upon the causation of the disease have not given uniform
results, and it does not seem possible at present to place
responsibility for this condition upon any particular form of diet, such
as deficiency of fat or excess of carbohydrates or protein. It appears
to be true that the prolonged use of any food leading to nutritional
disturbance causes an inability on the part of the bone cells to take up
calcium salts in the normal manner.

While there are many obscure points with regard to the origin of both
scurvy and rickets, there is no doubt that some dietary shortcoming lies
at their base, and that they can be cured or altogether avoided by
maintenance of suitable nutritional conditions.


THE FOODS MOST COMMONLY POISONOUS

Certain articles of food figure with special frequency in the reports of
food poisoning outbreaks. It is not clear in all cases why this special
liability to inflict injury exists. For an example, vanilla ice-cream
and vanilla puddings have been so often implicated that some
investigators have not hesitated to ascribe a poisonous quality to the
vanilla itself. But there is no good evidence that this is the case, and
it has been suggested that the reducing action of the vanilla favors the
growth of anaërobic bacteria which produce poisonous substances, an
explanation highly conjectural.

The conspicuous frequency with which the consumption of raw meat
provokes food poisoning has already been set forth and in large part
explained by the occasional derivation of meat from animals infected
with parasites harmful to man. The even greater culpability of raw milk
is due to the fact that milk is not only, like meat, sometimes obtained
from an infected animal, but that it is a particularly good culture
medium for bacteria, and in the process of collection or distribution
may become infected through the agency of a human carrier. Foods such as
ice-cream that are prepared with milk are also often connected with food
poisoning. It seems probable that illness caused by ice-cream is much
more commonly due to bacterial infection than to poisoning with metals
or flavoring extracts. The responsibility of these latter substances is
entirely problematic.

Cases of cheese poisoning, which apparently are relatively numerous, are
of quite obscure causation. Whether such poisoning is due more commonly
to some original contamination of the milk, or to an invasion of the
cheese by pathogenic bacteria in the course of preparation, or to the
formation of toxic substances by bacteria or molds during the process of
ripening which the cheese undergoes, is left uncertain in the majority
of cases.

Shellfish poisoning from eating oysters, mussels, or clams is
unquestionably caused in some instances by sewage contamination of the
water from which the bivalves are taken, and in such cases bacilli of
the typhoid or paratyphoid groups are commonly concerned. It is a
disputed question whether certain recorded outbreaks of mussel poisoning
have been due to bacterial infection or whether sometimes healthy or
diseased mussels taken from unpolluted water contain a poisonous
substance. In a similar way it is uncertain whether a certain marine
snail (_Murex bradatus_), sometimes used for food, contains under
certain conditions a substance naturally poisonous for man, or whether
it is poisonous only when it is infected or when toxigenic bacteria have
grown in it.

Potato poisoning has been attributed in some cases to bacterial
decomposition of potatoes by proteus bacilli; in other cases, to a
poisonous alkaloid, solanin, said to be present in excessive amounts in
diseased and in sprouting potatoes. It is noteworthy that many instances
of potato poisoning have been connected with the use of potato salad
which had stood for some time after being mixed, so that the possibility
of infection with the paratyphoid bacillus or other pathogenic organisms
cannot be excluded. That solanin is ever really responsible for potato
poisoning is considered doubtful by many investigators.

These examples are sufficient to show that in a considerable proportion
of cases of alleged food poisoning there is a large measure of
uncertainty about the real source of trouble. Although the trend of
opinion has been in the direction of an increased recognition of the
share of certain bacteria, especially those of the paratyphoid group,
there is an important residue of unexplained food poisoning that needs
further skilled investigation. It is one of the objects of this book to
point out this need and to draw attention to the numerous problems that
await settlement. The first step is the regular and thorough
investigation of every food poisoning outbreak.


FOOTNOTES:

[114] Jordan and Harris, _Jour. Infect. Dis._, VI (1909), 401.

[115] _Ibid._

[116] E. B. Vedder, _Jour. Amer. Med. Assoc._, LXVII (1916), 1494.

[117] McCollum and Davis, _Jour. Biol. Chem._, XXIII (1915), 181.

[118] Goldberger, _Jour. Amer. Med. Assoc._, LXVI (1916), 471.

[119] MacNeal, _Jour. Amer. Med. Assoc._, LXVI (1916), 975; Jobling,
_Jour. Infect. Dis._, XVIII (1916), 501.

[120] Gasbarrini, _Policlinico_, November 14, 1915; abstract, _Jour.
Amer. Med. Assoc._, LXV (1915), 2264.

[121] Holst and Frölich, _Jour. Hyg._, VII (1907), 619; Moore and
Jackson, _Jour. Amer. Med. Assoc._, LXVII (1916), 1931.

[122] Jackson and Moody, _Jour. Infect. Dis._, XIX (1916), 511.



INDEX


  A

  Acid pickles, 33

  Adulteration, food, 41

  Agglutination, 60, 64, 70

  Alkaloid, 107

  Allergy, food, 6

  Almonds, 11

  _Amanita_:
    _aurantiaca_, 20;
    _caesaria_, 18, 20;
    _muscaria_, 18, 19, 20, 22;
    _phalloides_, 21, 22, 23;
    _verna_, 22

  "_Amanita_ toxin," 22, 24

  Anaphylaxis, 9, 10, 11

  Aniline dyes, 32

  Animal parasites, 79

  Animals, 13, 14, 24, 44, 50, 67, 68, 70, 71, 72, 78, 93, 95, 100, 106;
    emergency-slaughtered, 59, 62, 63, 65, 72

  Ankylostomiasis, 83

  Annatto, 32

  "Anti-anaphylaxis," 11

  Antimony, 27

  Antiseptic chemicals, 33, 40

  Antitoxin, 24;
    diphtheria, 9

  Appendicitis, 1

  Arsenic, 26, 101

  Arteries, 3

  Artichokes, 16

  _Ascaris_, 84

  Asiatic cholera, 50

  Asparagus, 30, 31

  Asthma, 10, 12

  Atropin, 20


  B

  Bacillus:
    _botulinus_, 92-96;
    _coli_, 56;
    Danysz, 75;
    _diphtheriae_, 69;
    _enteritidis_, 58, 59, 60, 63, 64, 65, 66, 67, 68, 69, 70, 71,
      72, 74;
    _enteritidis-suipestifer_, 70, 72;
    _paratyphoid-enteritidis_, 68, 69, 85;
    _paratyphosus_, 58, 66;
    _paratyphosus_ B, 60, 65, 66, 73, 74;
    _proteus_, 55, 56, 57, 107;
    _suipestifer_, 65, 66, 67, 68, 71, 72, 73, 74;
    tetanus, 69;
    tubercle, 44, 51, 52, 53;
    typhoid, 44-47, 64, 106

  Bacteria:
    food-borne, 44, 58;
    pathogenic, 44, 58

  Bacterial products, 85

  Balloon-fish, 24

  Barbel, 25

  Beans, 14, 31, 46, 86, 88, 95, 104

  Beef stew, 59

  Beer, 26, 27

  Benzoate of soda, 34

  Benzoic acid, 34, 35, 36

  Beriberi, 102

  Berries, 29, 35

  Birds, game, 97

  Biscuits, soda, 36

  Blood vessels, 2, 39

  Borax, 37

  Boric acid, 37, 38, 40

  Botulism, 86;
    anatomical lesions, 91;
    bacteriology, 92;
    cases, 87;
    epidemiology, 93;
    prevention and treatment, 94;
    symptoms, 88

  Bread, 47, 48

  Butter, 16, 32, 40, 101

  Butyric acid, 95


  C

  Caffeine, 36, 41

  Cakes, 76

  "Calf diarrhea," 72

  Candies, 27, 28, 32, 41

  Canned foods, 4, 5, 7, 8, 29, 30, 95

  Canning, 33, 93

  Cap, metallic, 28

  Cardamom, oil of, 16

  Carriers, 55;
    paratyphoid, 61, 62, 66, 67, 70, 73, 78;
    typhoid, 45, 48, 50, 66

  Cases of:
    botulism, 87,
      listed by Mayer, 88,
      in U.S., 88-91;
    dysentery, 84;
    food sensitization, 10, 11, 12;
    milksickness, 100;
    mushroom poisoning, 20, 21, 22;
    plant poisoning, 14;
    poisoning from asparagus, 30;
    trichiniasis, 80, 81;
    tuberculosis, 53

  Cat, 83

  Cathartics, 96

  Cattle, 10, 51, 53, 54, 55, 62, 63, 71, 72, 74, 82, 86, 96, 100

  Celery, 45, 46, 47

  Cereals, 12, 62

  Cestode infection, 82

  Cheese, 5, 7, 28, 97, 106

  Chemicals, antiseptic, 33, 40

  Chicken, 71, 88

  Chick pea, 103

  Chicory, 41

  Chocolate, 28

  Cholera microbe, 51

  Chopped beef, 59

  _Cicuta maculata_, 14, 16, 17

  Cinnamon, 37

  Clams, 50, 106

  _Claviceps_:
    _paspali_, 86;
    _purpurea_, 85, 87

  Codfish, 67

  Coffee, 36, 41

  Coffee-tree, 14

  Coloring, artificial, 40

  Coloring substances, 31

  _Conium maculatum_, 15

  "Contact infection," 62, 67

  Cook, 44, 45, 50, 73, 74

  Copper, 30, 101

  Copper:
    acetate, 31;
    salts, 31;
    sulphate, 31, 32

  Cranberries, 35

  Creosote, 34

  _Cysticercus cellulosae_, 82, 83


  D

  Daffodil bulbs, 14

  Danysz bacillus, 75

  Death Camas, 14

  Death-cup, 21, 23

  Death-rates, 2, 3, 4, 39

  _Delphinium_, 14

  Diarrhea, 84

  Diet, defective, 102, 103, 104, 105

  Diphtheria, 54

  Diseases:
    deficiency, 101;
    degenerative, 2;
    milk-borne, 54;
    skin, 12

  Dog, 25, 83

  Drying, 33, 40

  Dyes, aniline, 32

  Dysentery, 84


  E

  _Echinococcus_, 83

  Eczema, 10, 12

  Eelworm, 84

  Eggs, 6, 10, 11, 12, 97, 98

  Egg-white, 9, 10, 11, 12

  Epidemics. _See_ Outbreaks

  Ergot, 85

  Ergotism, 85-86

  "Expectation of life," 2

  Extracts, flavoring, 106


  F

  Favism, 104

  Fish, 5, 24, 25, 34, 62, 67, 71, 83

  Flies, 47

  Flour, 32, 43, 103

  "Fly _Amanita_," 18, 19, 21

  Fly poison, 18

  Food:
    adulteration, 41;
    allergy, 6;
    coloration, 32;
    intoxication, 18, 57, 92;
    preservatives, 33;
    substitutes, 16, 41

  Foods:
    canned, 4, 5, 7, 8, 29, 30, 95;
    cooked, 47, 51, 52, 53, 54, 60, 63, 69, 70, 78, 81, 94;
    decomposed, 39, 97;
    most commonly poisonous, 105;
    protein, sensitization to, 9;
    smoked, 34, 39;
    spoiled, 39, 97;
    uncooked, 7, 46, 47, 48, 55, 63, 69, 70, 79, 84, 94, 96

  Foot-and-mouth disease, 55

  Formaldehyde, 36, 40

  Fowl, 5

  Fruits, 5, 10, 29, 30, 35, 47, 50, 62, 97, 104

  "Fruit ethers," 42

  Fruit syrups, 42

  _Fugu_, 25

  Fungus, 85


  G

  Gallstones, 1

  Game birds, 97

  Gastro-enteritis, 56, 60, 74, 96

  _Giardia (Lamblia) intestinalis_, 84

  Globe-fish, 24

  Glucose, 27, 41

  Goose, 71;
    liver, 78

  Grain, 85, 104

  Grass, wild, 86

  _Gymnocladus dioica_, 14


  H

  _Hackfleisch_, 59

  Ham, 86, 92, 94, 95

  Hamburger steak, 59, 78

  Hay, 104

  Hay fever, 9

  Heart, 3, 22

  Heating, 40

  Hellebore, 14

  Hemlock, 13, 15;
    poison, 16;
    water, 14, 16, 17

  Hippuric acid, 35, 36

  Hog cholera, 66, 71

  Honey-locust, 14

  Hookworm infection, 83

  Horse, 71, 86

  Horseradish, 16

  Hydatid disease, 83

  _Hydrocarpus_, 16

  _Hymenolepis nana_, 82


  I

  Ice, 75

  Ice cream, 5, 7, 32, 105, 106

  Infection:
    accidental, 72;
    Asiatic cholera, 50;
    _Bacillus proteus_(?), 55;
    bacterial poisons, 86, 96;
    carrier, 44, 45, 48, 50, 55, 61, 62, 66, 67, 70, 73, 78;
    cestode, 82;
    _Giardia (Lamblia) intestinalis_, 84;
    hookworm, 83;
    laboratory, 72;
    milk-borne, 54;
    parasitic, 79;
    paratyphoid, 58;
    scurvy, 104;
    secondary bacterial, 80;
    soil, 46;
    tapeworm, 82;
    tuberculous meat, 51;
      tuberculous milk, 53;
    typhoid food, 44

  Intoxication, food, 18, 57, 92

  Iron pyrites, 26


  J

  Jams, 27

  Japanese _Fugu_, 25

  Jars, preserve, 28

  Jelly, 32, 50


  K

  _Kalmia latifolia_, 14

  Kidneys, 2, 3, 22, 24, 39

  Kittens, 84


  L

  Larkspur, 14

  Lathyrism, 103

  Laurel, 14

  Lead, 27

  Lead:
    chromate, 28;
    foil, 28;
    pipes, 28;
    salts, 29

  Legumes, 104

  Lettuce, 45, 50

  Liver, 22, 24;
    goose, 78

  Loco-weed, 14

  Lupines, 14


  M

  Maize, 103

  Maratti-oil, 16

  Margarin, 16

  Marsh-marigold, 14

  Mary Malloy, 45

  "Measly pork," 83

  Meat, 5, 7, 24, 33, 37, 40, 44, 51, 52, 53, 57, 58, 59, 62, 63, 64,
      65, 68, 69, 70, 71, 72, 75, 76, 77, 78, 79, 83, 95, 97, 101, 106;
    jellies, 69;
    pies, 69, 73;
    puddings, 69

  Meat inspection, 77, 81

  Metals, 5, 106

  Mice, 56, 74, 75, 78, 84

  Milk, 5, 6, 7, 10, 11, 40, 48, 50, 51, 53, 54, 55, 62, 69, 70, 72,
      73, 76, 77, 96, 97, 101, 104, 106

  Milksickness, 100-101

  Molasses, 30

  _Murex bradatus_, 107

  Muscarin, 22

  Mushrooms, 5, 13, 18-24

  Mussels, 50, 106

  "Mutations," 68


  N

  Neuritis, 26

  "Neurotoxin," 24

  Nipples, rubber, 27

  Nissl granules, 91

  Nitrogen peroxide, 32


  O

  Oatmeal, 11

  Oats, 104

  Oil of cardamom, 16;
    of cloves, 37

  Olive stones, 41

  Outbreaks due to:
    beans, Darmstadt, 95,
      Stanford University, 95;
    beef, Breslau, 58;
    beef stew, Limerick, 59;
    beer, England, 26;
    bread, Elgin, 48;
    codfish, 67;
    diseased animals, 71;
    ergot, Limoges, 85;
    gastro-enteritis carrier, 74;
    group and family in U.S., 4, 5;
    ham, Ellezelles, 92;
    human contamination, 73;
    list of, by:
      Hirsch, 85,
      Hübener, 58,
      Mayer, 65,
      Savage, 58;
    margarin, Hamburg, 16;
    meat, 65, 69;
    Frankenhausen, 63,
      Ghent, 77;
    meat pies, Wareham, 73;
    milk, 96;
    Kristiania, 73,
      Newcastle, 69;
    miscellaneous contaminations, 74;
    mushrooms, New York City, 18;
    oysters, 48;
    paratyphoid carrier, 73;
    pie, Westerly, 60;
    potato salad, 65;
    public markets, South Philadelphia, 46;
    rat virus, 75;
    sausage, 65,
      Hanover, 56,
      Württemberg, 86;
    "sour grass soup," New York City, 18;
    spaghetti, Hanford, 44;
    typhoid carrier, New York City, 45;
    _Vanille Pudding_, 65;
    vermicelli, 67;
    watercress, Philadelphia, 46;
    water hemlock, New Jersey, 16

  Oxalic acid, 18

  _Oxyuria_, 84

  Oysters, 5, 24, 48, 49, 50, 71, 106


  P

  Palmolin, 16

  _Panaeolus papilionaceus_, 21

  "Paragaertner" forms, 68

  Parasites, 79, 84

  Paratyphoid fever, 58-78;
    carriers, 61, 62, 66, 67, 70, 73, 78;
    diseased animals, 67, 71;
    gastro-intestinal, 61;
    general characters of, 61;
    human contamination, 73;
    means of prevention, 77;
    miscellaneous contaminations, 74;
    sources of infection, 71;
    symptoms, 61;
    toxin production, 68;
    typhoid-like, 61;
    typical outbreaks, 58

  Parrots, 72

  Parsnips, 16

  Pasteurization, 48, 54

  Pastry, 47

  Paté de foie gras, 78

  Peas, 31, 43, 46

  Pellagra, 102, 103

  Pepper, 41

  Pericarp of rice, 102

  Peripheral neuritis, 26

  Pickling, 93

  Pidan, 98

  Pie, 60

  Pigs, 71

  Pike, 25

  Pinworm, 84

  Plant oils, 16

  Plants, 9, 13-24, 25, 101

  Poisons:
    bacterial, 96;
    chemical, 26;
    mineral, 26;
    organic, 26;
    protoplasmic, 33

  Poisoning by:
    aniline dyes, 32;
    animals, 24;
    antimony, 27;
    arsenic, 26;
    Asiatic cholera infection, 50;
    _Bacillus proteus_(?) infection, 55;
    botulism intoxication, 86;
    coloring substances, 31;
    copper, 30;
    defective diet:
      beriberi, 102,
      favism, 104,
      lathyrism, 103,
      pellagra, 103,
      rickets, 105,
      scurvy, 104;
    egg-white, 9;
    ergot, 85;
    fish, 25;
    food preservatives, 33;
    food substitutes, 41;
    lead, 27;
    milk-borne infections:
      diphtheria, 54,
      foot-and-mouth disease, 55;
    milksickness, 100;
    scarlet fever, 54,
      and septic sore throat, 55;
    mushrooms, 18;
    parasites, animal:
      teniasis, 82,
      trichiniasis, 79,
      other, 84;
    paratyphoid infection, 58;
    plants, 13;
    shellfish, 24;
    tin, 29;
    tuberculosis infection, 51;
    typhoid infection, 44

  Poisoning, food:
    articles of food most commonly connected with, 7;
    effects of, 2;
    extent of, 3;
    frequency of, 1;
    kinds of, 6;
    means of prevention, 2;
    obscure, 100;
    outbreaks of, in United States, 3, 4, 5;
    reports of, 3, 4, 8;
    scope of book, 6;
    seasonal incidence of, 5;
    unknown, 100

  Poison-ivy, 14

  "Poison squads," 34

  Pollen, 9

  Polyneuritis of fowls, 102

  Pork, 79

  Pork and beans, 88

  Potatoes, 46, 107

  Potato salad, 65

  Preservatives:
    chemical, 33;
    food, 33;
    household, 37

  Proteins, 9, 11, 12, 62, 69, 80

  Protochloride of tin, 30

  "Ptomain poisoning," 1, 3, 18, 68, 97

  Puffers, 24

  Pulse, 103

  Pyrites, iron, 26


  Q

  Quinine, 33


  R

  Rabbit, 71

  Rachitis, 105

  Radishes, 45

  Rash, 10, 12

  Rats, 56, 74, 75, 78, 81, 82

  "Rat virus," 75

  Refrigeration, 33, 40

  Rice, 43, 102

  Ricin, 14

  Rickets, 105

  Ripening, 97

  Roundworm, 79

  "Royal _Amanita_," 18

  Rye, 85


  S

  Saccharin, 41

  Salad, 5, 95, 107;
    dressing, 95

  Salicylic acid, 36

  Salt, 33, 41, 94

  Salt solution, 33, 40

  Salting, 33

  Saltpeter brines, 33

  Sandwiches, 46

  Saponin, 42

  Sausage, 5, 7, 40, 56, 65, 69, 75, 78, 79, 86, 88

  Scarlet fever, 54

  Scurvy, 55, 104

  Sensitization, food, 6, 9

  "Septic sore throat," 55

  Serum, antitoxic, 96;
    blood, 11, 64, 65, 70;
    therapeutic, 9

  Shark, 25

  Sheep, 71, 100

  Shellfish, 10, 24, 106

  Shrimp, 71

  Smoking, 33, 93, 94

  Snail, 107

  "Soda water," 42

  Sodic carbonate, 36

  Sodium benzoate, 34

  Sodium fluoride, 40

  "Soft drinks," 28, 42

  Soil, infected, 46, 47

  Solanin, 107

  Solder, 28

  Sorrel, 18

  "Sour grass soup," 18

  Sour milk, 97

  Spaghetti, 44

  Spices, 37

  Staphylococcus, 96

  Stoppers, patent metal, 28

  Strawberries, 10

  "Streptococcus sore throat," 55

  _Strongyloides_, 84

  Strychnine, 33, 96

  Sturgeon, 25

  Substances, coloring, 31

  Substitutes, food, 16, 41

  Sugar, 26, 28, 41, 42

  Sugar solution, 33, 40

  Sulphite, 36, 40

  Sulphurous acid, 26, 27, 36

  Swine, 74, 80, 81, 82, 93

  Symptoms:
    cholera-like, 25, 77;
    circulatory, 10;
    coma, 22;
    constipation, 89, 90, 100;
    convulsions, 20, 22, 25;
    coryza, 10;
    diarrhea, 10, 21, 61, 90;
    difficulty in swallowing, 20;
    digestive, 1, 61, 105;
    dizziness, 20, 90;
    eyelids, edematous, 10;
    febrile anemia, 104;
    fever, 61, 79;
    gastro-intestinal, 1, 10, 58, 61, 90;
    hemoglobinuria, 104;
    jaundice, 104;
    mental, 24;
    nausea, 10, 12, 88;
    nervous, 10, 24, 90, 103;
    pain:
      abdominal, 21, 61, 89,
      muscular, 79, 80;
    paralysis, 25, 96;
    rapidity of appearance of, 10, 44, 58, 61, 91;
    rash, 10, 12;
    sneezing, 10;
    temperature, subnormal, 89, 100;
    thirst, 21, 89;
    trismus, 20;
    visual, 20, 88, 89, 90, 91, 96;
    vomiting, 10, 12, 21, 88, 90, 100

  Syrups, 27, 42


  T

  Tapeworm, 82, 83

  Tea, 36

  _Tenia saginata_, 82

  Teniasis, 82

  _Tenia solium_, 82

  Tetrodontidae, 24

  Theobromine, 36

  Tin, 29-30

  Tin salts, 30

  "Toadstools," 18

  Tomatoes, 12

  Toxin, 68

  Trembles, 100

  Trichina, 79

  _Trichinella spiralis_, 79, 80

  Trichiniasis, 79

  Trichinosis, 79

  Tuberculin, 9

  Tuberculosis, 44, 51

  Typhoid fever: 44-50, 78, 79;
    carriers, 45, 48, 50, 66;
    milk-borne, 48


  U

  Uncinariasis, 83

  Urticaria, 10

  Utensils, cooking, 27, 28, 30


  V

  Vanilla: 105;
    ice cream, 105;
    pudding, 65, 105

  Vegetables, 5, 29, 30, 31, 45, 46, 47, 62, 83, 95, 97, 104

  _Veratrum viride_, 14

  "Verdigris poisoning," 31

  Vermicelli, 67

  "Vitamin," 102, 103


  W

  Water, 28, 50, 75

  Watercress, 45, 46

  Wintergreen, 14


  Z

  _Zygadenus_, 14



Transcriber's Notes:


Passages in italics are indicated by _underscore_.

Passages in fracture style are indicated by +fracture+.

This book contains 1 chemical formula on page 20: C{5}H{15}NO{3} the
numbers in brackets should be read as subscripts.

Illustrations have been moved from the middle of a paragraph to the
closest paragraph break.

The punctuation in the index was inconsistent, all semi-colons in
listings for page numbers have been changed into commas, they are not
specially mentioned/marked in the list of changes. Subentries are in
general separated by semi-colons, these have been added or changed from
other punctuation marks silently. Sub-subentries are in general
separated by commas, these have been added or changed from other
punctuation marks silently.

Atropin and atropine have been retained in both versions in
this project.

Table A in footnote [1] contains a potential mathematical error, the
2nd column (Expectation of Life 1879-81), row (Ages) 40 shows the value
23.0, it should be 23.9 to add up correctly in the 4th column (Gain or
Loss). The original value (23.0) has been retained.

Footnote [2] "also Doerr, "Allergie und Anaphylaxis," in Kolle" is cited
often as "also Doerr, "Allergie und Anaphylaxie," in Kolle". It has been
retained in the version printed in the book for authenticity reasons.

Margarin (pages 16 and 112) is in general spelled margarine, it has been
retained in this book for reasons of authenticity.

Maratti-oil (pages 16 and 112) is in general known as moratti-oil, it
has been retained in this book for reasons of authenticity.

Hydrocarpus (pages 16 and 111) is in general known as Hydnocarpus, it
has been retained in this book for reasons of authenticity.

Amanita caesaria (pages 18, 20, and 109) is also known as Amanita
caesarea but retained for this project in the first form.

Muscarin (pages 20, 21, 22, and 112) is in general spelled muscarine, it
has been retained in this book for reasons of authenticity.

Zygadenus (pages 25 and 115) is in general known as Zigadenus, it has
been retained in this book for reasons of authenticity.

The typhoid carrier in New York Mary Mallon (aka Typhoid Mary) mentioned
on page 45 as well as on page 112 is spelled in this book as Mary
Malloy, the original of the book has been retained.

Other than the corrections listed below, printer's inconsistencies
in spelling, punctuation, hyphenation, and ligature usage have
been retained.

The following misprints have been corrected:

  added 0 to +.89 in table B footnote [1], second to last value
  in 4th column.

  changed "la face vulteuse" into "la face vultueuse" page 21

  changed "Paneolus papilionaceus" into "Panaeolus papilionaceus"
  page 21

  the italic mark-up for "XLV" in "f. öffentl. Ges., XLV" has been
  removed, footnote [69]

  changed "R. Trommsdorff, L. Rajchmann, and A. E. Porter," into "R.
  Trommsdorff, L. Rajchman, and A. E. Porter," footnote [82]

  changed "Paneolus papilionaceus" into "Panaeolus papilionaceus"
  page 113





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