534 Transactions of tiie 



I sluill speak of all globules less than this figure as granules, and all 

 above as globules. Every sample of milk 1 have yet examined has shown 

 these granules, yet in some milks much more abundant than in others. 

 In the skim-milk the granule lias always !>cen readily found, even when 

 rare in the cream. These globules, being composed of various fats sur- 

 rounded by a pellicle, :ti'e intimately mixed with the milk as it comes 

 from the cow, but their position soon becomes changed as they come 

 under the influence of gravity; they rise to the surface of the milk to 

 form cream. 



"Having established the fact that the size of the globule determines 

 some of the reactions in the churn, we will consider the. effect of churn- 

 ing milk containing 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 oftentimes, 

 being overchurned, hinder the same process from going on with the 

 same facility for the breaking of the smaller globules. The overclaim- 

 ing of the butter destro} T s the grain, or the natural form in which the 

 butter is contained in its investing 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 

 product is, therefore, theoretically retarded and diminished. 



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" The milk of the Jersey cow contains a larger globule than does the 

 corresponding milks of the other breeds we are considering. The 

 granules, if present, are but few in number. 



"The milk of the Ayrshire cow furnishes a globule intermediate in 

 size between the Jersey and the Dutch. The prominent feature of this 

 milk is the numerous granules. 



"The Dutch milk showed a globule smaller than in the other breeds. 

 The presence of granules is not a prominent feature, although there were 

 more present than in the corresponding Jersey milk. 



" The properties of the globules also show some breed variations. The 

 envelope to the Jersey globule seems weaker than the corresponding 

 envelope in the other breeds, and more readily broken. This covering 

 in the Jersey milk globule is also more readily acted upon by the chem- 

 ical changes induced in the milk by time. When the old cream of these 

 breeds is examined microscopically, it is found that the Jersey globule 

 is more readily broken or distorted by pressure than the others. Prac- 

 tically, therefore, this milk should be skimmed at an earlier period of 

 the souring change than should the other milks. I am certain, from im- 

 pressions gained from my own experiments, that the Jersey milk should 

 be skimmed certainly not later than when the milk commences to 

 thicken or "lobber" at the bottom of the pan, while the Ayrshire milk 

 should pass considerably beyond this point, and develop somewhat more 

 acidity before the cream is removed. 



"It will be also found that the cream which rises from the milk of 

 these three breeds will not mix again with the milk with the same 

 facility. 



"The milk of the three breeds was placed in a bottle and the cream 

 allowed to rise, the bottle being corked to prevent evaporation from the 



