354 On the Disintegration of Ralid Brain Substance. [July 10, 



Accordingly an emulsion, made by adding disintegrated rabid brain 

 substance to 10 parts of physiological salt solution, was intimately 

 mixed with a virulent brain pulp in the proportion of five parts of the 

 former to one of the latter, and the mixture allowed to stand at the 

 room temperature for 24 hours, it having previously been ascertained 

 that a l-in-60 emulsion of " virus fixe " in physiological salt solution 

 retains its virulence for this period of time. Intra-cerebral injection 

 of the mixture of disintegrated and virulent brain substance, practised 

 upon rabbits, was followed by rabies, thus showing the absence of a 

 rabicide substance in disintegrated rabid brain. 



It might seem not improbable that the virus would be destroyed by 

 so low a temperature as that of liquid air. But it has been ascer- 

 tained by Dr. A. MacFadyen that exposure of rabid brain substance 

 to the temperature of liquid air for three months fails to deprive it of 

 its virulence. 



From the above facts it seems difficult to arrive at any other con- 

 clusion than that the infective agent in rabies is deprived of virulence 

 by mere mechanical violence, a result which could only be explained 

 on the hypothesis that the virus is of the nature of a living organism. 



Brain substance disintegrated by the method above referred to, and 

 mixed with physiological salt solution in the proportion of 1 in 10, 

 when injected intra-cerebrally into a rabbit in doses of O'l c.c. and 

 upwards, often causes convulsions terminating in recovery or death 

 according to the dose. An equal amount of a l-in-10 brain pulp, 

 made by trituration in a mortar, similarly injected, is usually without 

 effect. Convulsions are producible whether the cerebral substance used 

 is healthy or rabid, fresh or kept for some time previously in glycerine. 

 Hence these convulsive phenomena, whatever be their explanation, have 

 no bearing on the nature of rabies. 



As regards the main issue raised in this research, the experiments 

 appear to furnish strong confirmation of the view that the virus of rabies 

 is organised in its nature.' 





