242 AGRICULTURAL BACTERIOLOGY. 



haps thousands, of dairies, where commercial cultures have 

 been adopted in one. 



The method of making this natural starter is simple. There 

 may be various plans, but one which is satisfactory enough is 

 as follows : A perfectly healthy cow from a cleanly, well-kept 

 dairy is selected. After the under parts of the body are care- 

 fully brushed, and the udder moistened with a damp cloth, the 

 first few jets of milk from the teats are rejected, and the rest 

 are drawn into a sterilized vessel. This is then covered at 

 once and taken to the dairy, heated to a proper temperature 

 and passed through a separator. The skim milk thus ob- 

 tained is again collected in a sterilized vessel, carefully cov- 

 ered and set aside to sour. After it has become properly 

 soured it serves as a starter for the cream-ripening process. 

 Of course, there are many other ways of obtaining a natural 

 starter, for a natural starter is nothing more than a lot of skim 

 milk or whole milk, obtained under specially cleanly condi- 

 tions from an exceptionally good dairy, and allowed to sour 

 naturally. 



It is impossible for the dairyman to be sure that a natural 

 starter contains the species of bacteria desired for ripening. 

 Sometimes it may contain the proper species, and at other 

 times an unfavorable species. Logically, then, the use of a 

 natural starter is very unsatisfactory. But dairymen are not 

 so much interested in the logic of the method as in the 

 practical results, and care not whether the process they use is 

 theoretically the best, provided it gives them a good quality 

 of butter. There can be no question that the use of natural 

 starters thus made has been a very decided advantage to the 

 butter-maker in the last ten years. If it were not so we 

 would not expect this method of ripening cream to have been 

 so widely adopted and so generally, one might almost say 

 uniformly, recommended by butter-makers. 



We may properly ask why a natural starter, thus prepared, 



