there are other and weightier objections to experiments on animals.—In
the first place, the poison which has caused death may have been either
in part or wholly vomited before-hand, or absorbed, or transmitted into
the intestines, or decomposed by the process of digestion. Secondly,
though abounding in the matter vomited or which remains in the stomach,
it may be so much diluted, as not to have any effect on an animal. And,
thirdly, the animal fluids secreted during disease are believed to act
occasionally as poisons.
The first two objections are so plainly conclusive as scarcely to
require any illustration. It may be well, however, to mention as a
pointed practical lesson, that Professor Orfila once detected a
considerable quantity of arsenic in the contents of the stomach, where a
prior investigation had shown that the same article produced no effect
on two animals, and where the reporters from this and other
circumstances declared, that in their opinion death was not owing to
poison.[111]
The last objection is a very important one; but there is reason for
suspecting that it has been a good deal exaggerated by medical
jurists.—Animal fluids are certainly poisonous when putrid. The repeated
and fatal experience of anatomists, together with the precise
experiments of M. Gaspard and M. Magendie,[112] leave no doubt that
putrid animal fluids, when introduced into an external wound, cause
spreading inflammation of the cellular tissue; and although Magendie
says he has found such fluids harmless when introduced into the stomach
of dogs,[113] it is probable, from their effects on man, that they will
act as irritants on animals not habituated to their use. I believe, too,
that independently of putrefaction, vomited matter or the contents of
the stomach may be apt to make dogs vomit on account of their nauseous
taste; and perhaps we may infer, that they will also cause some of the
other symptoms of poisoning with the irritants, particularly if not
vomited soon after being administered.—As to the influence of disease in
rendering the contents of the stomach deleterious, it is to be observed
that the effects just mentioned are probably owing to the influence of
disease on the secretions, but that beyond this we know very little of
the subject. In authors I have hitherto found only one fact to prove
that disease can render the contents of the stomach decidedly poisonous;
and on the negative side of the question there exists no facts at all.
Morgagni describes the case of a child who died of tertian ague, amidst
convulsions, and in whose stomach a greenish bile was found, which
proved so deleterious, that a little of it given with bread to a cock
caused convulsions and death in a few minutes, and a scalpel stained
with it, when thrust into the flesh of two pigeons, killed them in the
same manner.[114] It is not easy to say what to think of this
experiment; which, if admitted to the full extent of the conclusions
deducible from it, would lead to the admission, that disease may impart
to the secretions the properties of the most active narcotics. Farther
researches are certainly required before this admission can be made
unreservedly.
On the whole, it appears that in the present state of our knowledge,
experiments or accidental observations on the effects of the contents of
the stomach, or of vomited matter, on animals are equivocal in their
import. At the same time it may be observed, as with regard to articles
of food, drink, or medicine, that the effects of some poisons on man may
be developed so characteristically on animals by the contents of the
stomach, as to supply very pointed evidence indeed. Of the force of this
statement the following example is a striking illustration. In the case
of a girl, who was proved to have died of accidental poisoning with
laudanum, the inspector evaporated the contents of the stomach to
dryness, made an alcoholic extract from the residue, and giving this to
several dogs, chickens, and frogs, found that they were all made
lethargic by it, some of them oftener than once, and that a few died
comatose.[115] Facts such as these, agreeing so pointedly with the known
effects of the poison suspected, appear to me to yield evidence almost
unimpeachable.