THE RELATION OF MICROORGANISMS TO MILK 437 



not thrive in the udder. The types of organisms commonly found 

 there do not seem to develop rapidly in the milk when it is held at low 

 temperatures and fail to produce any appreciable changes in it during 

 the normal life of market milk. 





FIG. 139. Colonies developing in agar plate held for ten seconds in position of 

 milk pail after udder was brushed gently with the hand. 



Diseased Udders. If, however, the cow is suffering from disease 

 in the udder, the bacterial condition may be quite different from that 

 described above. In this case, the milk may be filled with the specific 

 bacteria before it leaves the udder. In cases of inflammatory trouble or 

 tuberculosis in the udder the milk may contain very large numbers of or- 

 ganisms, frequently many millions per c.c. at the time the milk is drawn. 



