Hydrophobia is a disease brought on by inoculation with the saliva of a rabid animal, and characterized by intermitting spasms of the muscles of respiration, together with a peculiar irritability of the body and disturbance of the mind.

Symptoms In The Dog

The first symptoms of rabies in the dog are an unusual shyness and melancholy. The animal avoids society, refuses his food, and seems to have lost all his vivacity; his ears and tail droop, he looks haggard and suspicious, his eyes are red and watery, and he is constantly snapping at and swallowing straws, litter, and rubbish, and licking cold surfaces, such as stones or iron. In the next stage the respiration become difficult, and there is a copious flow of viscid saliva, with inflammation of the fauces, and fever. The animal is by no means so invariably furious as is generally supposed; and it has, in the course of experiments, not always been easy to induce it to bite. Yet it may be said that there is always a greater disposition than usual to bite if irritated; -and in some instances there is a state of extreme rage, the animal attacking and biting indiscriminately every person and thing that comes within its reach. It has been presumed that the former milder form occurs in the domesticated and educated dog;-and that the state of uncontrollable and indiscriminate fury is met with chiefly in ill-tempered or wild dogs, and in wolves, foxes and the other unsubjugated varieties of the canine race. Be this, however, as it may, the breathing becomes more difficult and laborious as the disease advances; tremors and vomiting occur, and the animal is carried off in convulsions. It rarely survives the fifth day. The difficulty of swallowing water, which gives the name of the disease as it occurs in man, is very rare in animals.

Causes

The cause of this malady in dogs is most frequently infection from another animal already diseased; yet it must occasionally arise spontaneously. The most probable sources of its origin are close confinement, rank, unwholesome food, want of the couchgrass, the natural medicine of the dog, and deprivation of sexual intercourse.

Besides the dog, it is probable that hydrophobia arises spontaneously in the wolf, jackal, badger, and perhaps the cat. But it may be communicated to many other mammiferous animals, and there is no doubt but that every animal capable of taking the disease can also propagate it. This is equally true with regard to human beings as to animals. MM. Magendie and Breschet inoculated two healthy dogs on the 9th of June, 1813, with the saliva of a man who was labouring under the disease, and who died of it the same day at the Hotel-Dieu. One of the dogs ran away; but the other was affected with decided rabies on the 27th of July following, and died of it;-and some other dogs which it was made to bite, died also. Well-authenticated cases are recorded, in which the disease was communicated to man by pigs and horses;-and there is no doubt but that it would be bo much more frequently, if it were the instinct of herbivorous animals to show their rage by biting. Breschet, in the course of numerous experiments on the subject, repeatedly infected dogs with the saliva of rabid horses and asses. One curious fact demonstrated by these experiments is, that when rabbits, or other rodentia, and birds, are inoculated with the saliva of rabid animals, they very soon die, but without exhibiting any of the ordinary symptoms of Hydrophobia.

In the horse the disease commences with great distress and terror and profuse sweating; he soon becomes frantic and outrageous, stamping, snorting and kicking. In the sheep the symptoms are similar. An instance is recorded in which eight sheep were bitten, and became rabid; they were exceedingly furious, running and butting at every person and thing, but did not bite. They drank freely.

There are several points connected with the propagation of Hydrophobia, which are still involved in great uncertainty. It is not known whether the saliva is the poisonous agent, or whether some poisonous matter may be secreted by the mouth, fauces or lungs, and mixed with the saliva. This, however, is not a point of much consequence; but again, it is uncertain whether the whole solids and fluids of the animal are not poisonous also. In fact, there is some reason for believing that the disease may be communicated by the mother's milk. Moreover, it appears that it may be communicated by contact of the dog's saliva with the mucous membrane of the mouth, without any wound or abrasion. In a case related by Dr. Watson, the dog's tooth merely indented the skin of the back of the hand, but made no wound. Lastly, a point of more importance and uncertainty than any is, whether the bite of an animal in health, or of one merely enraged, may not cause the disease; or, at all events, supposing it to be really infected with rabies, whether its bite may not be dangerous during the period of incubation, and long before the outbreak of any apparent symptoms.

Symptoms In Man

These may be divided into three stages.

First, the stage of incubation, being that which intervenes between the infliction of the bite and the first appearance of the disease. This period is exceedingly various. It is seldom less than forty days;-generally from five weeks to three months. But authors are by no means agreed as to its limits. Dr. Bardsley positively denies that the malady ever comes on after more than two years from the bite; and attributes the cases said to have occurred after that time to "anomalous causes," or to inoculation from some unsuspected source. Other authors, on the contrary, seem to think that it may occur at any indefinite period-even twelve years after inoculation. Dr. Burne relates the case of a prisoner in the Milbank Penitentiary, who died of it seven years after he was bitten. The unfortunate man had indeed kept two cats in his cell, and it is possible that he might have received the infection from one of them. They were however, alive and well at the time of his decease. It must be concluded, therefore, either that Hydrophobia may come on seven years after a bite;-or that it may be communicated by animals who are to all intents and purposes healthy. But if a surgeon is questioned on the subject by a person who has been bitten, it will be his duty to allay his apprehensions as far as possible. He may very safely assure him, that after six months have elapsed, the chance of the disease is very slight indeed;-and that scarcely more than a twentieth of those bitten by dogs really mad are ever affected.