BACTERIA IN BUTTER-MAKING. 237 



the best quality of butter is made without pasteurization or pure 

 cultures. However, these exceptionally fine grades of butter 

 do not represent the ordinary product, and the average is 

 judged to be somewhat inferior to " culture butter." While 

 then, the highest grade of butter is not improved, the general 

 average of the butter made by the process in question is higher 

 than the general average of butter made without cultures. 

 But it has become very clear that the use of pure cultures will 

 not make the highest quality of butter if the cream is of poor 

 quality. It is just as desirable to have good cream now as it 

 was before the use of pure cultures. While the quality of 

 butter made from poor cream may be improved by the use of 

 pasteurization followed by pure cultures, some effects of the 

 inferior quality of cream will remain. Experiments have 

 shown that the use of pasteurization with pure cultures will 

 not correct the errors due to slovenliness in dairy matters. It 

 is just as necessary that care should be taken in all details as 

 it was before cultures were adopted. 



In general dairy practice, the results have been, perhaps, more 

 favorable than in experimental tests. This is doubtless due to 

 the fact that the dairy has a great variety of difficulties to con- 

 tend with which can be more readily eliminated in experimental 

 tests than in general practice. If the use of pure cultures, 

 therefore, is of any value in correcting errors that come from 

 carelessness, it is very clear that the use of such cultures in 

 general practice, where carelessness is to be expected, would 

 be more valuable than would appear from the experimental 

 tests where carelessness can be eliminated. Several years' use 

 of such cultures have shown that an advantage is gained in at 

 least three different points. 



First : this method enables the butter-maker to handle his 

 cream much more easily and uniformly. He can regulate the 

 ripening in such a way that his cream will always be of a cer- 

 tain grade of ripeness at a certain time of day ; for a little ex- 



