RABIES 609 



present any great difficulty where the symptoms are pro- 

 nounced and the animal observed through the different 

 stages. The positive proof of a bite inflicted previously 

 by another animal is of considerable importance in mak- 

 ing the diagnosis. An accurate diagnosis is of great impor- 

 tance for two reasons, viz.: (a) In case human subjects are 

 bitten, or in any way inoculated, it will give them an oppor- 

 tunity to receive the antirabic treatment early; and (b) 

 to protect other animals and persons from becoming inocu- 

 lated by quarantining and confining the animal. Under no 

 circumstances should an animal showing symptoms of rabies, 

 or suspected of having the disease, be killed. It should 

 be put in quarantine and observed. It has been demon- 

 strated that animals destroyed early in the disease often 

 do not show positive findings on microscopic examination. 

 The characteristic symptoms of irritation, tendency for 

 biting, change of voice, paralysis, etc., generally show evi- 

 dence enough to the experienced clinician to establish the 

 diagnosis. The detection of Negri bodies on microscopic 

 examination will make the diagnosis positive. In dumb 

 rabies the diagnosis is made on the characteristic symptoms 

 of paralysis of the lower jaw, the somnolence in most cases, 

 the expression and the paralysis of other parts of the body 

 in the course of two to four days. All cases showing the 

 symptoms of the lower jaw hanging down should be diag- 

 nosed dumb rabies until ample proof is shown that it is some 

 other condition. Microscopic examination of the brain 

 should be made to establish the diagnosis as in furious 

 rabies. Intracranial inoculations of rabbits have been used 

 extensively in making a positive diagnosis. This method 

 requires from fourteen to seventeen days, and is falling 

 into disuse. Inoculations of the virus in guinea pigs have 

 also been used extensively as a diagnostic measure. 



Prognosis and Course.— The disease is fatal in practically 

 all cases. The possibility of recovery in very mild cases 

 cannot be denied. However, no authentic case of recovery 

 has been recorded. It has been estimated that only about 

 17 to 20 per cent, of the animals bitten by known rabid 

 animals develop rabies. This percentage is higher in dogs 

 than in any other small animal. The course of the disease 

 39 



