168 



NORIIAL MILK : ITS ADULTERATIONS, ETC. 



TABLE XXXVII. — Variations in Composition of Milk on 

 Standing (Large Churn). 



In another experiment two large churns, such as are used in 

 restaurants, each holding 12 quarts, were stood side by side ; 

 every quarter of an hour 1 quart was drawn from the tap and the 

 amount of fat in each portion was estimated (Table XXXVIII.), 

 The residue was not analysed, but undoubtedly contained a high 

 percentage of fat. 



TABLE XXXVIII. — Variations in Composition of Milk on 



Standing (Small Churns). 



It is seen from the results of these experiments, which are 

 typical of many, that milk left to stand remains approximately 

 of the same composition for short periods only — not exceeding 

 half an hour; by continually drawing off the bottom layer, 

 samples are obtained which become poorer and poorer in" fat 

 till the upper layer of cream is reached. 



A similar phenomenon is observed, if the milk is dipped from 

 the top of a counter pan, as the following experiment will show : — 



Three quarts of milk were placed in a pan ; every half-hour 



