618 RABIES AND THE NEGRI BODIES 



preparation. The immune serum is standardized, according to Kraus, 

 with a fixed virus prepared fresh from the medulla of a rabbit in 

 the proportion of 1 part emulsified with 100 parts of physiologic salt 

 solution and filtered through a paper filter to remove the remaining 

 coarse particles. Antiserum and virus are mixed in varying propor- 

 tions and are allowed to stand for twenty-four hours at room tem- 

 perature. The mixtures are then injected subdurally into various 

 animals. While Kraus, like Babes and others, succeeded in destroying 

 the fixed virus by mixing it with antiserum, he never succeeded in 

 obtaining any protective influence by injecting the antiserum even 

 in large doses into animals which were subsequently infected with 

 rabies. 



QUESTIONS. 



1. What are the other scientific and common names for rabies? 



2. How long has the disease been known? Where does it occur? 



3. How is it generally spread in natural infection? 



4. When does the saliva of a dog suffering from rabies become infective ? 



5. What animals are susceptible to rabies? 



6. Discuss the period of incubation of rabies. May it be prolonged to one 

 orjnore years? 



7. What explanation suggests itself as to such a long period of incubation? 



8. What percentage of people bitten by rabid dogs develop rabies? What 

 percentage of dogs bitten by other dogs? 



9. What is probably the behavior of the rabies virus after its entrance into 

 the body of persons and animals? 



10. What are the different forms of rabies? 



1 11. Describe the symptoms of furious rabies in a dog. Also of dumb rabies. 

 * 12. What is the consumptive form of rabies? 



13. Does recovery from rabies in dogs occur? 

 * 14. Describe the symptoms of rabies in man. 



15. Describe the postmortem findings on a dog dead from rabies. 



16. Describe the changes of Van Gehuchten and Nelis in the cervical and spinal 

 ganglia in rabies. 



17. What are the Negri bodies? In what parts of the central nervous system 

 would you look for them? 



18. Describe their morphology in the brain of a dog dead from rabies. 



19. What is the meaning of street virus and of fixed virus? 



20. What is the difference between the Negri bodies in street and in fixed 

 virus cases? 



21. Are the Negri bodies found in the earliest stages of rabies? If not, what 

 practical measures should be adopted in the diagnosis of rabies by the aid of the 

 Negri bodies? 



22. Give in detail the steps in the rapid microscopic diagnosis of rabies in the 

 dog. 



23. Describe the best fixing and staining methods used in this rapid diagnosis. 



24. How should material from a suspected rabid dog be prepared for sub- 

 sequent laboratory examinations ? 



25. What are the opinions as to the nature of the Negri bodies? 



26. What are the peculiar biologic properties of the Negri bodies which enable 

 them to survive as a race of intracellular parasites? 



27. How does the virus of rabies spread in the body of susceptible animals 

 from its portal of entrance to the central nervous system? 



28. Describe the method to inoculate rabbits subdurally with the street virus 



29. How is the fixed virus prepared from the street virus? 



30. How long is the period of incubation of the fixed virus inoculated sub- 

 durally? 



31. Is the fixed virus in subdural inoculation virulent for animals other than 

 rabbits? 



