PROPHYLACTIC IMMUNIZATION OR VACCINATION 637 



is an acute infectious disease in which the diagnosis is quite readily 

 made, and whenever possible an effort should be made either to confirm 

 or to disprove the diagnosis by making an examination of the animal's 

 brain, and if the dog is found to have been free from rabies, this fact 

 should be carefully impressed upon the patient, as otherwise the dread 

 of infection may weigh heavily upon the patient and lead to distressing 

 nervous disturbances. 



While the infectiousness of rabies has been known for a great many 

 years and was proved experimentally by Galateir 1 and Pasteur, 2 it was 

 not until Negri, in 1903, described certain bodies (Negri bodies), seen 

 by him in large nerve-cells in sections of the central nervous system, 

 that anything was found that seemed absolutely specific for rabies. 

 Negri regarded these bodies as specific for rabies and probably of a 

 protozoan nature. Later investigations fully established the diagnos- 

 tic value of these bodies, and their definite characteristic morphology, 

 evidences of cyclic development, and staining qualities indicate a 

 protozoan structure resembling members of the Rhizopoda, designated 

 by Anna Williams in 1906 3 as Neurorrhyctes hydrophobia. 



Rembringer, 4 Poor and Steinhardt, 5 Bertarelli and Volpino 6 have 

 demonstrated the filterability of the rabic virus, and Noguchi 7 has cul- 

 tivated from both " street" and " fixed" virus, very minute granular 

 and somewhat coarser pleomorphic chromatoid bodies which, on sub- 

 sequent transplantation, reappeared in the new cultures through many 

 generations and reproduced typical symptoms of rabies in dogs, rabbits, 

 and guinea-pigs. 



To Pasteur is due the credit for having discovered (1880) the fact 

 that the disease may be prevented by conferring gradual immunization 

 with increasing doses of the attenuated virus. This treatment, with 

 some modification, is now used with evident success in all parts of the 

 world. 



Nature of Rabies. The virus or parasite is contained in the saliva 

 of the rabid animal, and infection is possible when the skin is abraded 

 by bites and scratches. The virus travels by way of the nerve-paths 



1 Compt. rend. Acad. d. sc., 1879, Ixxxix, 444. 



2 Compt. rend. Acad. d. so., 1881, xcii, 159. 



3 Proc. N. Y. Path. Soc., 1906, vi, 77. 



4 Ann. de PInst. Pasteur, 1903, xvii, 834; 1904, xviii, 150. 

 6 Jour. Infect. Dis., 1913, xii, 202. 



6 Centralbl. f. Bakt., Orig., 1904, xxxvii, 51. Bertarelli, ibid. 



7 Jour. Exper. Med., 1913, xviii, 314. 



