ENZYME-FORMING BACTERIA. 



79 



The liquefying bacteria include bacilli, bacteria and cocci 

 (Fig 1 . 16). They are abundant in fresh milk, apparently 



A variety of bacteria liable to be found in milk, i and 2, typhoid bacillus (Pfeiffer) ; 3, 

 pus and pus cocci; 4, B. dysenteric (Shigar) ; 5, Proteus vulgaris ; 6, Clostridium buty- 

 ricus ; 7, 9, 10, n, types of common lactic bacteria ( Conn) ; 8, a coccus without influence on 

 milk ( Conn) ; 12, 13, 14, three bacilli producing slimy milk (Fig. 12, Marshall', Figs. 13 and 

 14, Conn) ; 15, 16, 17, 18, 19, types of liquefying and putrefying bacteria, which digest the 

 casein (Conn). 



coming from sources external to the cow, since the bacteria 

 that are in the milk ducts are not liquefiers, as a rule. They 

 are found in abundance in the feces of the cow and in various 

 forms of filth, and the presence of large numbers of liquefiers 

 in a sample of fresh milk is an indication that it is badly 

 contaminated by bacteria. Indeed, the quality of milk, from 

 a bacteriological standpoint, may be with tolerable accuracy 

 estimated by the number and proportion of liquefiers which 

 it contains. If the number of bacteria is large but they 



