Anti-Rabic Serum 417 



the pericellular space, and an invasion not only of this 

 space, but also of the nerve-cells by embryonal cells, and 

 at the same time small corpuscles which are hyaline, brown- 

 ish, and in parts metachromatic. Spiller * does not regard 

 the lesions as pathognomonic of rabies. 



If an accurate diagnosis of rabies can be made, in cases 

 where animals thought to be mad have bitten human beings, 

 by a simple histologic examination, much time can be saved 

 in beginning the Pasteur treatment and probably an in- 

 creased number of cases saved. 



Protozoa and Hydrophobia. The inability of the modern methods 

 to enable us to demonstrate the presence of bacteria in rabies, has led 

 many to conclude that the disease depends upon some animal parasite, 

 and the recent contribution of Negri | is very suggestive. 



Negri found that by staining sections of the cerebrum, cerebellum, 

 pons, basal ganglia and sometimes even the spinal ganglia, of human 

 beings or animals dead of rabies, by Mann's methylene-blue and eosin 

 method, it was possible to demonstrate in the interior of the nerve- 

 cells of their protoplasmic process, red colored, rounded bodies measur- 

 ing 4 to 10 fj., as a rule, though varying from 1 to 25 /*, unlike anything 

 seen before and highly suggestive of parasites. In experimental infec- 

 tions under the dura they were most numerous in the hippocampal con- 

 volution. These bodies have now become known as Negri's bodies. 



As the parasitic nature of these bodies is suggested only by the cir- 

 cumstances under which they are found and their morphology, it is not 

 demonstrated that they are of etiologic importance. 



Anti=rabic Serum. The serum of animals that have 

 received repeated injections of the crushed nervous tissue of 

 rabid animals is neutralizing or destructive to the rabies 

 virus in vitro, and is called anti-rabic. It was first men- 

 tioned by Babes and Lepp,J who thought it exerted a de- 

 pressive power upon other animals. Marie finds that this 

 reaction is specific as simple neurotoxic serum i. e., serum 

 of an animal given repeated injection of crushed normal 

 nervous tissue is inert in its action upon the virus. The 

 activity of the anti-rabic serum is also found to be in propor- 

 tion to the virulence of the virus, and quantity of the virus 

 introduced into the experiment animal. 



* Pathological Society of Philadelphia, March, 1901. 

 f'Soc. Med.-chirurg. di Pavia," 24, in, 1903. 

 t "Ann. de 1'Inst. Pasteur," 1889, in. 



"Compt. rendu Soc. Biol.," t. LVI, June 18, 1904, p. 1030. 

 27 



