BACILLUS PESTIS 



393 



kidneys, walls of the stomach and intestines, urine, and 

 intestinal contents of fresh cadavers; and during life in the 

 blood, expectorations, feces, and urine of persons sick of the 

 disease. From these findings the infection is obviously a 

 septicemia. 



FIG. 73 

 A 



'<*/"' C < 



^ ' " '41 



Bacillus of bubonic plague: A, in pus from suppurating bubo; B, the 

 bacillus very much enlarged to show peculiar polar staining. 



It is negative to the Gram method but stains readily with 

 the ordinary aniline dyes. It may be cultivated upon 

 ordinary nutrient media, although preference is given by 

 some to a neutral or slightly alkaline 2 per cent, peptone 

 solution containing from 1 to 2 per cent, of gelatin. 



The most favorable temperature for its growth is between 



