230 RABIES. 



infliction of the bite, which to secure successful inoculation 

 need not be extensive, the slighter abrasions being equally 

 dangerous with the deeper or more extensive wound. It has 

 been supposed that following the implantation of the virus, an 

 augmentation and change occurs to it, first at the point of 

 inception and afterwards throughout the body; that the 

 blood thus contaminated acts prejudicially on all parts 

 nourished by it, particularly on those of the nervous centre 

 situated in the medulla and anterior portions of the cord. 



This idea has so far support when we know that for some 

 timej until the development of the characteristic symptoms, 

 nothing abnormal may be observed at the seat of the wound, 

 and that at the period of the manifestation of the constitu- 

 tional symptoms there are evidently changes either of an irri- 

 tative or other character, as the attention paid to this part by 

 the animal itself clearly indicates. 



Occasionally the horse may be bitten while removed from 

 the observation of its owner or attendants, the wound inflicted 

 being of so trivial a character that no indications of its inflic- 

 tion may be detected, thus rendering the future development 

 of symptoms rather mysterious. That this disease may be 

 produced in the horse from the bite of one of its own species 

 under the influence of the specific poison is, from certain 

 somewhat analogous cases, highly probable ; the actual occur- 

 rence of it in this manner I am not aware of, the rabid dog- 

 having in all instances been the offending individual. 



Although the period which Ave are certain has intervened 

 between the infliction of the bite and the first symptoms of 

 illness is in our patient subject to considerable variation, we 

 have no authentic account of such lengthened periods of incu- 

 bation as are claimed for the disease in man ; from twenty to 

 forty days being the usual periods in the horse. 



h. Anatomical CJiaraders. — Although in many instances 

 structural changes and unnatural conditions of many and 

 various organs and structures are obvious enough, none of 

 them are so constantly present nor so uniformly marked in 

 their intensity or ascendency over all others as to enable us to 

 regard them as diagnostic. In some the lesions in connection 

 with the nervous system are more distinctive than changes 

 observed elsewhere ; with other cases the digestive and circu- 



