184 A MANUAL OF BACTERIOLOGY 



spinal cord and the medulla oblongata of dogs dead 

 of rabies. 



The author has also observed a micrococcus (Fig. 

 40B) in the saliva of a woman suffering from 

 hydrophobia. 1 The micrococcus, which is deeply 

 stained by methylene blue, measures from 0'6 to 

 0*8 fj, in diameter. This microbe does not occur in 

 healthy human saliva. 



We cannot say that the microbe of rabies has 

 been isolated with anything like success, for the 

 above investigations do not fulfil Koch's canons (see 

 Chapter i.) to ascertain the pathogenic nature of the 

 microbe or microbes in question. It is probable 

 that the virus of rabies will not develop in the 

 absence of a living pabulum, and in all probability 

 it is not possessed of powers of active resistance to 

 those injurious influences which act upon it when 

 exposed to the air, etc. In fact, the virus of rabies 

 cannot survive the drying, changes of temperature, 

 etc., it necessarily undergoes when scattered over the 

 ground, as we often see happen by the slobbering of 

 a rabid animal. 



The saliva of rabid animals does not contain a 

 ptomaine, for when it is diluted with a small 

 quantity of sterilised distilled water, and then 

 heated to 90 C. for a few hours, the saliva loses its 

 virulent power. This proves that no alkaloid was 

 present, because it would not have been destroyed 

 on the application of heat. 2 Besides, M. Nocard 



1 The saliva was kindly sent to the author by Dr. T. M. 

 Dolan, of Halifax. 

 3 Griffiths' Researches on Micro-Organisms, p. 193. 



