78 INFECTION AND IMMUNITY 



('charbon') Acquired as a Result of Protective In- 

 oculations." 



In this communication, he reports his success in 

 conferring immunity upon five sheep by means of 

 protective inoculations, and also upon four young 

 dogs. We must, therefore, accord him the priority 

 in the publication of experimental data demonstrating 

 the practicability of accomplishing this result. 



But it is especially to the experimental researches 

 of Pasteur that we are indebted for the development 

 of practical methods, which have been extensively 

 employed in protecting cattle, sheep, and swine from 

 the fatal effects of various infectious maladies, and 

 man from hydrophobia as the result of the bite of 

 a rabid animal. 



Pasteur's inoculations are made with an " attenu- 

 ated virus " that is, with a culture of a pathogenic 

 micro-organism which has a diminished degree of 

 virulence and which whei introduced into a suscep- 

 tible animal induces a non-fatal and comparatively 

 mild attack. 



The researches of Pasteur and of his followers in 

 this line of investigation show that pathogenic viru- 

 lence may be attenuated by prolonged exposure to 

 oxygen ; by exposure to a temperature a little below 

 that which would completely destroy vitality ; by 

 the action of certain chemical agents ; and, in some 



