166 BACTERIOLOGY FOR NURSES 



and some of the bacterial diseases, notably tetanus. 

 Pasteur's protective inoculation serum is also re- 

 garded as another proof that hydrophobia is due to a 

 specific microorganism, which is too small to be seen 

 with a microscope (ultra-microscopic). 



In the rabid animal and in man the virus is 

 contained in the saliva. Infection occurs through 

 the bite, bites upon an exposed surface such as 

 the face and hands being usually much more 

 serious than when the skin is covered by the 

 clothing ; in the latter case the clothing holds 

 back the saliva. Infection may also be carried 

 by the licking of an abraded surface by a rabid 

 animal. 



Hydrophobia occurs epidemically among wolves, 

 dogs, sheep, cattle, and horses; but wolves and dogs 

 are the most susceptible. 



There are two forms of hydrophobia: (1) furious 

 rabies, characterized by restlessness, and (2) dumb or 

 paralytic rabies. 



In animals the period of incubation is from three 

 to six weeks, the first symptoms being restlessness, 

 snapping, and tearing at all objects or persons, a 

 peculiar change in the tone of voice, followed by 

 spasms of the throat muscles upon attempts at 

 swallowing, with an abundance of sahva. General 



