278 
ANIMAL PATHOLOGY. 
cable by the halitus, or through the medium of effluvia, or by the 
slightest contact, as well as by inoculation. Mange, glanders, 
distemper, may be communicated or bred. Each has its own 
mode of action, and is governed by its own laws ; and experience 
alone can determine what that mode of action and those laws are. 
That which is known of one disease cannot with certainty be 
predicated of any other. Reasoning from analogy is delusive, 
dangerous, inadmissible. We appeal to facts, and to facts alone 
we bow. 
The real Facts of the Case. The Human Being. —Now, what 
is the fact here? I first take the human being. Hydrophobia, 
or the dread of water—spasmodic contraction of the pharynx, 
and a difficulty or dread of swallowing—may be produced by 
some state of high nervous excitation, and it runs its course and 
passes away: but the train of symptoms which we have de¬ 
scribed in a former lecture as constituting rabies, is so invariably 
connected with the influence of the rabid virus, that no medical 
man ever sees such a case without, at once, associating with it, 
and unhesitatingly affirming that it was produced by, contact 
with the virus of a rabid animal. In nine hundred and ninety- 
nine cases out of a thousand he obtains demonstrative proof of 
this. So uniform has been the experience of practitioners, that 
no one now pretends to assert that rabies ever arises spontane¬ 
ously in the human being. 
The Quadruped. — So uniform is the connexion between the 
appearance of rabies in the horse, cattle, sheep, and swine, and 
the knowledge or discovery of a previous bite by a rabid dog, 
that all veterinary surgeons are agreed that rabies, in these ani¬ 
mals, is caused "by inoculation alone: but it is maintained by 
some, that this disease may be produced spontaneously in carni¬ 
vorous animals—in the dog—the wolf—the fox, and some others. 
We ask for the proof of this. We ask for a single instance in 
which rabies can be shewn to have arisen from any other cause 
than inoculation. We are all agreed that it is the most common 
cause. I do not require too much when I demand a detailed 
account of a single supposed exception. 
Want of Ventilation a supposed Cause of Rabies. —Professors 
Coleman and Sewell both assert that rabies may be produced 
by imperfect ventilation—by heat—by thirst—by any thing, in 
fact, which will produce fever in the animal. Professor Coleman 
says, expressly, that he has made up his mind on one point, 
namely, that rabies may arise in consequence of dogs being ex¬ 
posed to their dung and urine, and to confinement, and to too 
much food, and too little exercise.” And in a letter sent to a 
committee of the House of Commons, he says, “ Hydrophobia is 
