EXPEEIMENTS WITH MILK. 



379 



Having established the fact, that the size of the globule 

 determines some of the re-actions in the churn, we will con- 

 sider the effect of churnino^ milk containins: globules of 

 widely different sizes. Whenever such trials have been made 

 and the results carefully noted, I have found that the larger 

 globules become divested of the covering first, and often- 

 times, being overchurned, hinder the same process from 

 going on with the same facility for the breaking of the smaller 

 globules. The overchurning of butter destroys the grain, or 

 the natural form in which the butter is contained in its invest- 

 ing coating, and releasing the oleine furnishes to the fluid, in 

 emulsion, this oil, which decreases the friction to which the 

 globules are subjected in order to produce butter. The prod- 

 uct is, therefore, theoretically retarded and diminished. 



Experiment IV. 



Carefully measured 16 fluid ounces of milk fresh from the 

 cow and cooled to 60° hy immersing the Florence flask used 

 as a churn in cold water. After twenty minutes churning 

 the butter was collected by straining the fluid through fine 

 linen. The amount, 59 grains, or a proportion of one pound 

 of butter to about sixty quarts of milk. The next day, churned 

 the buttermilk. Alter an hour and a quarter's agitation 211 

 grains of butter were collected. 



This milk threw up 12 per cent, of cream, and was, there- 

 fore, of good average quality, as was also indicated by the 

 butter proportion of one pound of butter to about thirteen 

 quarts of milk. 



We must seek the explanation of this experiment in the 

 physical re-action of the globules. 



Average of ten measurements of the globules occurring in a 

 line -^^Q inch in length : — 



