CHAPTER XXIII. 

 BUTTER. 



I. WHEN cream is violently agitated in a churn or 

 other vessel, the fat globules in it coalesce into larger or 

 smaller grains or lumps which are removed from the 

 separated serum or buttermilk and kneaded subsequently 

 into an apparently compact mass of butter. 



In this process it is as well to note that the fat 

 globules do not as a whole lose their separate identity, 

 but remain distinct and do not melt together as drops of 

 oil do when brought into contact with each other. 



Ex. 156. Mount small portions of cream taken from a churn 

 at various stages of the churning process up to the time when 

 the butter " comes." 



Press down the cover-slip. 



Examine with a in. and \ in. objective and note the 

 coalescence of the fat globules into small clusters. 



Ex. 157. Squeeze a very small piece of butter between the 

 slide and cover-slip and examine with a in. and \ in. objective. 



Is the butter homogeneous ? * 



Make drawings of what you see. 



It is practically impossible, by churning cream, to 

 obtain the milk fats, pure and free from serum, so that 

 butter always contains in addition to the fats a small 

 but appreciable amount of protein, milk-sugar, and mineral 

 substances as well as from 9 to 20 per cent, of water ; 



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