34 SOURCE OF BACTERIA IN MILK. 



the very depths of the milk ducts the milk may become 

 crowded with microorganisms. 



The kind of microorganisms that find their entrance into 

 milk from such sources is somewhat varied. The tubercle 

 bacillus thus undoubtedly sometimes finds entrance into the 

 milk from diseased udders. Indeed this is practically , the 

 only source from which this organism invades milk. Other 

 types of udder troubles contaminate the milk with bacteria, 

 of which there are several species. The more common 

 among them appear to be certain forms of streptococci (35). 

 The inflammatory troubles of the udders are usually asso- 

 ciated with the gro.wth of 

 streptococcus forms, and 

 Qo milk drawn from such ud- 



r\ o i ,., 



& ders is quite likely to be 



o QQ o O O^ - ' ifr filled with certain types of 



* ^jy? PJ^' W c streptococci. The question 



> O whether these streptococci 



o 

 . " render the milk tmwhole- 



" I AI' 'jijj" c . ' tively answered, but experi- 



j 'V* %%$Q & 



n o r. - ment has indicated that, at 



o w ^o n - , 



o ^ & ^ east m some cases, milk 



Milk as seen under the microscope; a, with StreptOCOCCi from SUCh 



bacteria; b, fat globules; c, pus cells or leuco- disCaSCdtldderS is Capable of 



producing intestinal disturb- 

 ances in experimental animals, and the conclusion is a strong 

 one that such milk is unwholesome for man (100). The fre- 

 quency of milk contamination by such diseased udders is 

 seemingly greater than would be imagined. Milk contains 

 quite frequently a greater or less abundance of pus. The 

 presence of a considerable quantity of pus must be looked 

 upon, in all cases, as indicating some inflammatory condition 

 of the udder that secreted the milk, and the presence of pus 

 is also undoubtedly associated with the presence in the milk 



