AGRICULTURAL BACTERIOLOGY. 



not been satisfied to depend upon such a method, which is 

 more or less irregular with changes in temperature, but has 

 come to use, more and more largely, pure cultures of bacteria 

 to introduce greater regularity in the process. In some oleo 

 factories, indeed, so fully aware are the makers of the extreme 

 significance of this matter of proper bacteria to the successful 

 manufacture of oleo products, that they have actually built 

 and furnished bacteriological laboratories, and employ bacteri- 

 ologists to keep a constant guard over the bacteriological fac- 

 tors in the oleo-making. They know full well that the value 

 of their product is dependent almost wholly upon their ability 

 to obtain a flavor which resembles butter, and they have 

 learned by experience that the flavor which they obtain is de- 

 pendent upon the type of fermentation going on in the milk 

 while it is souring. They have found it to their advantage to 

 keep this matter of bacterial control under strict observation, 

 and to-day they employ pure cultures in large quantities. 



It is a suggestive fact that the oleo-makers have more fully 

 come to appreciate the need of a proper regulation of bacteria 

 in the ripening of their milk than the butter-makers have in 

 the ripening of their cream. Every oleo-maker realizes the 

 necessity of a strict control over the ripening of milk and he 

 has, in recent years, come to recognize the necessity for the 

 use of pure cultures, in order to ensure a uniformly high grade 

 of product. Butter-makers have not come to this belief as yet, 

 and in far too large a per cent, of instances they allow the 

 cream-ripening to take care of itself, without any special at- 

 tempt on their part to control it. It is by no means sure that 

 the butter-maker must come to the use of pure cultures, but 

 it is certain that he ought to use every means which can be 

 suggested to him for properly starting and controlling the cream 

 ripening. If butter-makers were as careful in the ripening of 

 their cream as the oleo-makers are in the ripening of their milk, 

 it is likely that we might hear less of the quarrel between the 



