192 MODERN BIOLOGIC THERAPEUSIS 



The period of time that elapses between the 

 bite by the animal and the development of symp- 

 toms in the individual is known as the period of 

 incubation. This varies from ten days to six 

 months or longer. The majority of cases occur 

 before the end of the third month, the average 

 time being about 72 days. 



SYMPTOMS IN THE DOG 



Rabies presents at least two clinical types : 

 these are the excited, and the paralytic. It is 

 important that the early symptoms of rabies in 

 the dog be recognized ; for the bite of a dog may 

 communicate the disease three or five days prior 

 to the development of symptoms in the dog. At 

 this stage, the animal may be playful and affec- 

 tionate to an unusual degree; he desires to be 

 recognized and petted. Later, there is a marked 

 change in the voice to a hoarse howl, followed 

 by an unequal series of barks, lower in pitch 

 than is normal. The rabid dog becomes restless, 

 lying down and getting up again repeatedly. He 

 is easily startled, growls and barks on slight 

 provocation. 



In the excited type, the dog may suddenly 

 leave home, wandering off for many miles, to 



