188 



PATHOGENIC BACTERIA 



some favorable results after injecting dead organisms 

 during an attack. 



Bacterium Bulgaricum. Another organism not far 

 removed from the group just described, of practical 

 if not of pathogenic importance, is the milk-souring 

 bacillus. There are many varieties, but the one now 



FIG. 52. Bacterium bulgaricum. X 1000 diameters. (Piffard.) 



used most is the Bacterium bulgaricum of Massol. It 

 has the property of breaking up the fat of milk and 

 producing lactic acid. This butter milk or sour milk 

 is used in intestinal diseases (see p. 37) at the sug- 

 gestion of Metchnikoff. The large quantity of lactic 

 acid is inimical to many disease-producing, putrefac- 

 tive and fermenting bacteria that elaborate poisons, 



