350 
J. A. COUTURE. 
mencement I must confess that this argument of Mr. Fleming forces 
me to believe in the spontaneous development of rabies ; for the period 
of latency in this disease is so long that one might think that a dog has 
become rabid spontaneously, when he has been bitten years before. But 
the first case of this disease—how was it developed ? It cannot have 
happened by contagion. It must have originated spontaneously ; and 
what has happened then must occur now. But, as says Williams, the 
sources of spontaneous origin of rabies, how produced and when ob¬ 
tained by the victim, are circumstances which are hidden in obscurity. 
As I have already said, the chief cause of rabies is a specific virus 
contained in the saliva of a rabid animal, and which is introduced into 
the system ordinarily by the bite of a mad animal, and which may be 
transferred from the canine species to other animals and to man, and 
trom man to the canine species. From experiments made in Paris, two 
dogs became rabid from having been inoculated with the saliva of a 
mad young man.f However, all cases of inoculation have not positive 
results; the poison may be arrested in the clothing or medium through 
which the teeth pass in giving the wound. Persons and animals bitten 
by a rabid dog have died a short time after, when men, dogs, hogs, 
sheep and cats, bitten by the same rabid animal have escaped contagion 
ior the reason above mentioned, and probably also on account of that 
immunity which certain persons have with respect to the most contagi¬ 
ous affections. It results from experiments made by Hertwig, that six¬ 
teen inoculations with saliva taken from a rabid dog, either during life 
or soon after death, produced positive results in six cases ; six inocula¬ 
tions with saliva from cold cadaver, from 24 to 48 hours after death, 
resulted negatively in each case; thirteen inoculations from the tissues 
ot a rabid dog, produced one positive result ; fifteen inoculations by 
means of mad dogs, or by natural inoculation, produced four positive 
results ; five attempts at inoculation by means of intermediate vehicle 
(placing the subject in a stall where a mad dog had previously been 
kept), were negative.^ The shortest period of latency in dogs is seven 
days, and the longest one hundred and fifty-five days ; in man from 
three days to nine months, and even ten years in some instances ; in 
the hoise from fifteen days to three months, and even fifteen months ; 
m the sheep from fourteen days up to three months, and in the pig 
from eight or nine days, to as many months.§ Generally two-fifths of 
the individuals inoculated escape contagion. It will be seen by the 
* Fleming on Rabies and Hydrophobia. 
% Fleming. 
+ Grisolle. 
§ Williams. 
