Cornell University, Ithaca, N. Y., Dec. 7, 1898. 

 The Honorable Commissioner of Agriculture, 



Albanv, N. Y. 



Si?' : This bulletin is submitted for publication under Chap- 

 ter 67 of the Laws of 1898. 



The presence of gas, accompanied b}' undesirable taints in 

 cheese curd, has long been known to be a potent factor in lessen- 

 ing the market value of cheese. 



A few bacteriologists have found that the cause of the gas and 

 taints is a gaseous fermentation due to the presence of certain 

 bacteria. The particular species of bacteria which produce this 

 fermentation have not heretofore been clearly defined ; their 

 source or the channel through which they get into the milk has 

 not been definitely pointed out. W^hile, therefore, this trouble 

 has been attributed with reason to bacteria, the definite knowl- 

 edge of species and of means for carrying out intelligently pre- 

 ventive measures was wanting. 



The purpose of this bulletin is to point out one of the species 

 of bacteria which causes this trouble ; the channel through 

 which it gets into the milk ; and the precautions necessar}- to be 

 taken in order to prevent its appearance. 



It has been necessary to restrict the inquiry to the conditions 

 arising in a single factor}' and in a single dair}'. It cannot be 

 assumed, therefore, that the result obtained can without further 

 investigation be used to explain the cause of this trouble in all 

 factories. 



The investigation has brought out in a most conspicuous man- 

 ner the necessity' for a large amount of bacteriologic investiga- 

 tion in determining the effects upon milk, butter and cheese of a 

 large number of bacteria commonly present in the excreta of 

 cattle. 



This inquiry has brought out several facts, heretofore gener- 

 ally denied, concerning the source of bacteria in fresh milk. The 

 research demonstrates that bacteria do exist sometimes in the 

 milk ducts of the udder itself as well as in the teats. It is also 

 show^n that the same species of bacteria will persist in the udder 

 for a considerable time if once introduced. This is highly 

 important in showing the necessity for cleanliness in cow stables. 



The investigation, as a whole, has opened a new field and will 

 without doubt lead, in time, to extremely valuable results. The 

 only regret is that time and opportunity have not enabled the 

 Station to make as extended researches as is desirable. Suffice 

 it to say, the investigation will be continued another 3'ear. 



I. P. Roberts. 



