TO DOMESTICATED ANIMALS. 
337 
others, the vomited or dejected matters have been introduced 
into the subcutaneous tissue, into the veins, or into the 
alimentary canal ; lastly, animals have been made to breathe 
an atmosphere charged with the exhalations from cholera- 
blood and cholera-dejections. 
It will be found, as we proceed, that the earlier experi- 
ments of the Russian, Polish, French, and Italian physicians 
were objectionable or fruitless ; but, at least, we feel entitled 
to promise our readers, that those more recently performed 
have yielded more striking results, and possess certain claims 
to serious consideration. 
To some, indeed, it may probably appear that such an in- 
quiry must be wholly unprofitable to medical science. The 
pure contagionist, for example, might object, on the one 
hand, that the failure to extend the cholera by direct inocu- 
lation from man to animals would avail nothing against his 
theory of contagion, since cholera may be essentially a 
human pestilence; and, on the other hand, that even the 
production of a like train of symptoms in animals, would not 
significantly add to the reliable evidence of contagion already 
derivable from observations on the onslaught of the disease 
upon communities of men. To the pure non-contagionist, 
also, this experimental inquiry may seem, a priori, to be 
utterly futile ; for if genuine cholera did occur in the crea- 
tures submitted to experiment, might it not possibly be 
referable to the epidemic influence prevailing at the time ; 
whilst a negative result would but imperfectly support, by a 
questionable analogy, the views already deduced, in reference 
to man, as to the non-communicability of the disease from 
one individual to another? Lastly, by those who are induced 
to conceive that cholera, though essentially epidemic, may be 
contingently contagious, or essentially contagious while only 
contingently epidemic, each of the foregoing objections might 
in turn be urged against either positive or negative results. 
To the very obvious objection, that animals, even the 
nearest allied to man, differ so from him that no safe analogy 
can be drawn between them in regard to morbid phenomena, 
it may be responded, that the structure and economy of the 
higher animals render them liable to diseases, simple, conta- 
gious, or epidemic, more or less like those of the human 
species; that similarity of diet and community of abode 
especially approximate some of the domesticated animals to 
man ; and that certain specific diseases, the catalogue of which 
future inquiries may extend, are really, though with difficulty, 
capable of transmission from one to the other, though they 
may undergo modification in their transference. 
