RABIES 295 



Clinical Symptoms and Course. — The period of incubation lasts in 

 the majority of cases from three to six weeks. In very rare instances the 

 disease maj^ appear in one week. According to Haubner's observations 

 upon nearly 200 dogs, in 83 per cent, of the cases the disease developed in 

 two months; in 16 per cent, of the cases within three months; and in 1 

 per cent, four months, or even later. Zundel has calculated that in 264 

 dogs 1 per cent, became affected within twenty-four hours after being 

 bitten; 11 per cent, between the second and third day; 33 per cent, be- 

 tween the fifteenth and thirtieth clay; 19 per cent, between the thirtieth 

 and forty-fifth day; 10 per cent, between the forty-fifth and sixtieth day; 

 16 per cent, between the sixtieth and ninetieth day, and 10 per cent, 

 after three months. The longest period of incubation was observed by 

 Leblanc; this case developed in 364 days. The period of incubation is 

 shorter in young than in older dogs. In the human race it is generally 

 admitted that the average period of incubation is seventy-two days 

 (this average covers over 510 cases). 



There are two forms of rabies — a furious and mute (or dumb) form. 

 The first is more frequent, but there are numerous transitions between 

 the two forms; dogs that are at liberty or vagrant dogs are more apt to 

 have the violent or furious form, while dogs kept as house pets or who 

 are restrained are more frequently affected with the mute or dumb 

 form, and in dogs that are well trained and under control and have lived 

 in close contact with man, the tendency to bite is only present when they 

 have reached the point of true delirium and mental control is gone. 

 Pasteur found that intracranial injection produced furious rabies, while 

 subcutaneous injection almost invariably resulted in the dumb form. 



Furious Rabies. — This comprises three distinct stages, between which 

 there is a very distinct line of demarcation — namely, the prodrome or 

 melancholic, the stage of irritation, and the paralytic stage. 



In the melancholic stage the dogs seem to change in their disposition. 

 They are capricious, and at other times irritable or depressed. They show 

 symptoms of anger, are easily excited, fretful, change from one place to 

 another, are easily frightened on the slighest cause or may become very 

 affectionate. They soon show a tendency to gnaw or swallow indigestible 

 substances. They refuse their usual food, or they may take such food as 

 they have a special taste for, holding it in their mouth for a few moments 

 and then let it drop out of the mouth again. They will lick and gnaw, in a 

 greedy manner, various objects, such as wood, coal, furniture, and eat sti'aw, 

 earth, stones-, wood, blankets, and even their own fieces. In one case 

 observed by Govard, the animal would howl loudly, have an evacuation 

 of faeces and immediately eat it. There is commencing evidence of 

 paralysis in difficulty in deglutition, cough, and labored respiration. 

 The sexual desire is very much increased, and we see in the first stage an 



