166 



PATHOGENIC BACTERIA 



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 used most is the Bacterium bul- 

 garicum of Massol. It has the property of breaking up the fat 

 of milk and producing lactic acid. This buttermilk or sour 

 milk is used in intestinal diseases (see p. 35) at the suggestion 

 of Metchnikoff. The large quantity of lactic acid is inimical 



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



to many disease-producing, putrefactive, and fermenting 

 bacteria that elaborate poisons, the absorption of which 

 leads to intoxication to which Metchnikoff ascribed senility 

 and some specific diseases. This observer believed that the 

 health of certain people of the Balkan States could be ascribed 

 to drinking fermented mares' milk (koumyss). The various 

 sour milks now on the market are made by inoculating milk 

 with organisms of this kind. They are probably not superior 

 to domestically prepared buttermilk, if one has a good culture 



