THE MICEOBE OF BUTTER 91 



of butter proper, subsist on other qualities of the 

 cream, and convert them into substances which 

 give to the butter its fine flavor and aroma. 



Without the aid of these two species of microbes 

 there could be no good or fine flavored butter in the 

 world. Precious, indeed, are their services. 



Therefore these two species have been isolated 

 and formed each into a pure culture. These cul- 

 tures have been formed into two yeasts. These 

 yeasts have already been largely used in Europe 

 with fine success. They are now beginning to be 

 used in this country. There is no reason why their 

 use may not, in the near future, become universal. 



Of course, without the aid of these yeasts, 

 simply letting nature take its course, a fairly 

 good butter had been made during an indefinite 

 time in the past. Without their aid, too, an 

 equally good butter might supply the market dur- 

 ing an indefinite time to come. 



Yet every dairyman knows that, without the use 

 of these yeasts, failures have occasionally occurred 

 in all past time. It is certain that without their 

 use failures will at times occur in the future. 



But from experience already had, it is certain 

 that, with the use of these yeasts, such failures 

 may be reduced to a minimum, if not quite elimi- 

 nated. Certain that, with their use, a higher and 

 finer grade of butter may be made, with nearly, 

 if not quite, uniform success. 



The process is easy and simple. As soon as the 

 milk comes from the cows, let the separator do its 



