124 Report of the Department of Bacteriology of the 



upon the later germ life in the milk can be definitely stated. So far 

 as the data are now available the germ life in the udder does not 

 maintain itself very successfully in the competition which it meets 

 after being drawn. This is to be expected on account of the sudden 

 change in environment to which it is subjected. The oxygen 

 within the udder must be scanty if not absent and the temperature 

 is above 37° C. After being drawn the oxygen supply is markedly 

 increased while the temperature is usually rapidly decreased. 



While the udder flora as a whole probably does not persist in 

 the milk after it is drawn, some portions of it may do so. The 

 observations on cheddar cheese as quoted above make it probable 

 that a number of forms actually do persist for a considerable 

 period. Gorini 25 has ascribed to the acid-forming liquefiers of the 

 type of M. lactis varians a leading role in the ripening of hard 

 cheese. If this supposition is correct, it is evident that the udder 

 flora exerts a marked influence upon this important industry. 



It should not be assumed that with the disappearance of the 

 udder forms their influence upon the milk is entirely dissipated. 

 The work of Marshall and his students 20 has shown that even after 

 the total destruction of a given form it may leave such an im- 

 press upon the milk as to affect markedly the growth of the or- 

 ganisms which succeed it. 



It should also be remembered that the present study has not 

 taken account of the anaerobic flora of the udder, if such exists. 

 The natural lack of aeration in the udder is so great that the con- 

 ditions there would seem ideal for the development of a distinc- 

 tive anaerobic flora. 



It is much to be regretted that this study has not been more 

 complete along a number of lines but the removal of each of the 

 authors to other fields of activity has at least temporarily halted 

 the investigation. 



CONCLUSIONS. 



Many of the forms found in the udder are so accustomed to 

 relatively high temperatures that they do not develop satisfac- 

 torily at ordinary room temperatures. This fact should be con- 



25 Gorini, C. Ueber die saure-labbildenden Bakterien der Milch. Cent. 

 Bak. II Abt. 8:137-140. 1902. 



26 Marshall, C. E. Additional work upon the associative action of bacteria 

 in the souring of milk. Cent. Bak. II Abt. 12:593-597. 1904. 



