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 attache 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. oeffentl. 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._