ILLINOIS STATE DAIRYMEN'S ASSOCIATION. 22 I 



Since the bacteria which are in cream are so varied in their action, it 

 may be perhaps a matter of little surprise that the ordinary process of 

 cream ripening is so likely to give a good result, and that without any 

 artificial means of controlling the species of bacteria that may be present 

 a buttermaker can so commonly obtain a good product. The reason for 

 this, however, is apparently threefold. In the first place, although the^ 

 number of species "WTiich produce a favorable cream ripening is appar- 

 ently not so very great, these are species which are most common 

 around an ordinarily well kept dairy. Consequently if care is taken to 

 keep the dairy in good condition it is most likely that cream will be 

 especially supplied with species of bacteria which produce good results,, 

 and it is only under unusually improper conditions that the unfavorable 

 species become especially abundant. Secondly, there are reasons for be- 

 lieving that the species of bacteria which produce good results, under or- 

 dinary circumstances prove to be more vigorous than the others and. 

 grow so rapidly as either to crowd the others out of existence or to coun- 

 teract any effect which they may produce. Third, the temperature used 

 in ripening cream is such as to stimulate the growth of the favorable 

 species while it checks the growth of many other bacteria. Thus the 

 process of cream ripening is commonly satisfactory. But although this 

 is the case, buttermakers the world over are ever and anon troubled with 

 an improper type of cream ripening, and this makes it very desirable. 

 that if possible some means of controlling this process should be placed 

 in their hands. 



For a long time buttermakers have, to some extent, attempted to^ 

 control the ripening artificially by the use of "starters." For many years, 

 it has been the custom, at certain seasons of the year when the cream 

 does not sour quickly, to add at the beginning of ripening a certain 

 amount of soured milk or cream. The purpose for which this has been 

 done is not so much for controlling the character of the ripening as for 

 hastening it. The name "starter" indicates this. But it is at the same 

 time, we shall see later, a means of controlling the character as well as 

 hastening the rapidity of ripening. About ten years ago it was first sug- 



