HYDROPHOBIA 235 



susceptible animals (rabbits or monkeys). The disease is always 

 fatal after it is well established. Well-marked histological lesions 

 of the central nerve tissues, particularly the large ganglia, have 

 been found by Van Gehutchen and Nelis, and Ravenel and Mc- 

 Carthy. If emulsified brain tissue from an animal that has died of 

 hydrophobia is filtered through a "germ-proof" filter the filtrate is 

 capable of setting up the disease in a healthy animal if it is injected 

 into it. By long centrifugation of emulsified infected brain tissue, 

 the supernatant fluid loses its power of reproducing the disease on 

 injection. Virus may also be found in mammary and lacrymal 

 secretions, pancreas, cerebro-spinal fluid and aqueous humor. 



The organism is toxic in character, since filtrates sometimes fail 

 to produce transmissible disease, but emaciation, paralysis, and 

 death are caused by their injection into rabbits, the tissues of which, 

 in turn, are not infectious. 



The unknown organisms are rather resistant to agents that are 

 germicidal. They are destroyed in fifty minutes by a 5 percent 

 carbolic solution, and in three hours by a 1-1,000 corrosive sublimate 

 solution. Direct sunlight kills them quickly, so do radium emana- 

 tions. The latter have been used as a curative measure with 

 reputed success. A temperature from 52-58 C. for one-half hour 

 destroys them, but they resist extreme cold of liquid air ( 312) 

 for many weeks. Pasteur found that desiccation attenuated the 

 virus. Chlorine kills it quickly, while glycerine does not. The 

 virus may be increased in virulence by passing the "street virus" 

 of dogs through a series of rabbits. Here the period of incubation 

 decreases from three weeks to six days, but beyond this the period 

 does not become less, and the degree of virulence from the virus lead 

 Pasteur to name it virus fixe (fixed virus). 



Passing the virus through foxes, cats, and wolves also intensifies 

 the virulence, while monkeys and chickens attenuate it. 



Negri bodies, protozoon bodies discovered by Negri, are found in 

 the ganglionic cells of rabid animals. These bodies stain by eosin, 

 and are from one to twenty-seven microns in size, being generally 



