156 MICRO-ORGANISMS AND DISEASE [chap. 



Recent cultures of the diplococcus made from pneumonic 

 sputum or other exudations (mentioned above) inoculated into 

 mice or rabbits produce as a rule fatal septicasmic infection ; 

 the viscera are greatly congested, and the blood and viscera 

 contain abundantly the microbe. The same result is pro- 

 duced in the rabbit by injecting it with the rusty sputum of 

 croupous pneumonia prior to the fifth or sixth day. In the 

 blood and tissues of a mouse or rabbit that succumbed to 



FtG. 38.— Lung Juice of Guinea-pig dead after Infection with Micrococcus 



Tetragenus. 



X 1000. (A. Pringle.) 



infection, the diplococci are capsulated, and the capsules 

 can be as easily stained as those in the sputum or bronchial 

 exudation with eosin after the cocci themselves had been 

 stained with methyl-blue. Staining with gentian-violet in 

 alcoholic solution, and then carefully washing in water, shows 

 the cocci stained deep purple, the capsules light violet. 



Cultures that have been carried on for some generations 

 gradually lose the power to produce infection in the rodents, 



