Hydrophobia is _an acute specific or infectious disease_, as far as known _never originating in man, but transmitted to him, usually through the bite_ or by inoculation from the saliva of a _rabid animal_--in this country usually the dog, although the wolf, the cat, the skunk, and even certain of the domestic poultry, are capable of conveying the disease. Chickens are said to be immune save when their vital resistance is lowered by starvation. Chicken blood injected into other animals seems to antidote the virulence of the virus. It can also be inoculated in other animals, like rabbits. The _virus_ is ordinarily conveyed in the _saliva_ of the rabid animal. This may be wiped off as the teeth of the animal pass through the clothing of the injured individual; consequently, infection does not certainly follow such bites. But those upon exposed portions of the body, where animals generally bite, are almost invariably followed by infection. Hydrophobia is frequently spoken of as _rabies_, sometimes as _lyssa_. While rare in this country, it is by no means uncommon in Central Europe, especially perhaps in Russia, where bites from infuriated wolves are common. In the United States infection comes almost invariably from the rabid dog, in which this disease presents two types. The so-called _furious form_ is that which is marked by frenzy and canine madness, the objective symptoms being more pronounced and alarming, though not less dangerous than the other variety. After the period of incubation, which varies considerably, these animals show depression and uneasiness, and even thus early their saliva is infectious. Their sense of hunger becomes perverted; they exhibit unusual tastes, secrete saliva abundantly, which becomes very tenacious and even frothy, exhibit a dry and edematous condition of the faucial mucous membranes; the character of the bark is altered, while they are usually infuriated at the sight of other dogs. In this stage there is usually insensibility to pain. Finally, come more or less paralysis of deglutition, quickened respiration, dilated pupils, and frenzy and madness of manner, by which they attack indiscriminately men and other animals. To this stage of furious excitation succeeds one of paralysis, and death follows from exhaustion. These manifestations usually last about a week. _Dumb hydrophobia_ is the more common form. Here paralysis appears much earlier and involves especially the lower jaw; the tongue falls out of the mouth; and the posterior extremities are quickly paralyzed. This form is much more quickly fatal than the other.