46 PRACTICAL DAIRY BACTERIOLOGY 



The cause of such sliminess is, so far as known, the growth 

 of certain types of bacteria. Several different kinds have been 

 found capable of making milk slimy. The most common one of 

 these seems to be Bact. lactis viscosns (Fig. 24), which was 

 first described in Europe, and has later been found in a number 

 of such infections in America. This organism is widely dis- 

 tributed but, unless present in great numbers at the start, it 

 does riot, as a rule, develop in milk, since the growth of lactic 

 bacteria prevents its becoming very abundant. Although sev- 



FIG. 24 BACT. LACTIS VISCOSUS, THE COMMON CAUSE OF SLIMY MILK 



(WARD) 



eral other species of bacteria are able to produce slimy milk 

 they are not commonly causes of dairy troubles. Some va- 

 rieties of Bact. lactis acidi and Bact. aerogenes produce slimy 

 milk. 



A slimy milk infection is sometimes persistent, remaining in 

 dairies for weeks, and even months, and may be distributed 

 from one dairy to another until a large community is more 

 or less infected with the same trouble. One of the common 

 methods by which a large community may become infected with 

 such a trouble is through a central creamery or milk distributing 

 station. The trouble begins in some one dairy, and the milk 



