MILK. 177 



FORMATION OF BUTTER. 



Several explanations have been proposed with the view of 

 determining the exact cause of the amalgamation of the 

 cream globules with each other, and the formation of butter. 



Some have supposed that the trituration to which the 

 globules are subject in the churn determines their union and 

 incorporation with each other ; but it is known that the 

 amalgamation is not a gradual process, as it would be were 

 their union to depend upon trituration, but that it takes place 

 in a manner almost instantaneous : moreover, agitation might 

 fairly be presumed to have a contrary effect on the globules, 

 which participate in the properties of oil, and that it would 

 cause their further subdivision. 



A second hypothesis conceives that a chemical alteration 

 in the condition of the globules is determined by the presence 

 of the air : this has been shown to be erroneous by the fact 

 that butter will form in vacuo. 



A third theory presumed that an acid state of the milk 

 always preceded the formation of the butter : this notion is 

 disproved, since butter is formed of cream, the alkalinity of 

 which is purposely preserved by the addition of soda or any 

 other alkali. 



Donne thus explains the formation of butter : " The butter 

 globules," he says, " are surrounded in the cream by cheese in 

 a viscous state : this matter isolates the globules the one from 

 the other, and is opposed to their union. The churning 

 coagulates the cheese in which the globules are imbedded, 

 and, once separated from this, the grease globules unite and 

 agglomerate together easily." 



It is doubtful how far this explanation, though more satis- 

 factory than its predecessors, really accounts for the in- 

 stantaneous formation of the butter. 



