34 THE DISEASES OF THE DOG. 



public streets, or of some less bruised and injured dog which 

 has been more humanely but injudiciously destroyed after 

 infliction of a bite on its owner or someone who has had to 

 do with it. Such revengeful slaughter or prompt destruc- 

 tion with a view to prevent accidents is an error of 

 judgment, for if the dog had been kept alive with due 

 precautions his freedom from rabies might be established 

 on the clearest evidence, and thus the apprehensions of 

 persons bitten thoroughly allayed ; for it is almost certain 

 that no animal free from rabies, however angry he be, can 

 give another animal or man rabies by a bite. The dog 

 should be kept alive in order that it may be thoroughly 

 established that rabies was not incubating in his system. 

 The incubation of the disorder in the dog varies from a 

 week to a year, but it is highly probable that only during 

 the time immediately preceding and during active mani- 

 festations of the symptoms is it that the saliva is virulent. 

 Therefore keeping the animal alive for a short time, say 

 a fortnight, should suffice to prove whether he was in a 

 condition to convey the disease. It must be remembered 

 that the body of a dog in the latter stages of incubation 

 would present no definite and absolutely distinctive lesions 

 of rabies. However, when the disease has set in there 

 are some abnormalities detectable post mortem which 

 amply suffice for diagnosis. Even in a body considerably 

 advanced in decomposition (such as has sometimes to be 

 examined in this relation) the accumulation of foreign 

 bodies, generally of a nature not to readily decompose, 

 will be detectable in the stomach and at the back of the 

 mouth. In fresher cases the respiratory and alimentary 

 tracts should be examined with the greatest care, as also 

 the central organs of the nervous system (cerebro-spinal), 

 both macroscopically and microscopically. Increased 

 vascularity, a streaky congestion, is found at the base of 

 the tongue and sometimes invading the whole of the 

 fauces, especially the tonsils.. The upper part of the 

 larynx also, is a frequent seat of this lesion, and the whole 

 lining membrane of the trachea may be congested, or, in 

 severe cases, spotted. In the larynx the membrane about 



