INTRODUCTORY — THE CONSTITUENTS OF MILK. 



The results from th.e three experiments agree very well, con- 

 sidering the smallness of the actual quantities. 



From the results of experiments, in which cream was treated 

 with a 33 pet cent, solution of cane-sugar (used to promote the 

 separation of the layer of fat globules), and the fatty layer 

 separated, and the procedure repeated several times, Storcli 

 deduces the proportion of mucoid substance to fat as 38"4 to 100. 



From these experiments it is evident that cream containing 

 50 per cent, of fat should contain 19 per cent, of mucoid sub- 

 stance, and only 31 per cent, of the other constituents of milk ; 

 in other words, cream containing 50 per cent, of fat should, if 

 Storch's hypothesis be true, only contain /^'^ of the milk-sugar 

 in the skim milk. Analysis, however, shows that it actually 

 contains f'^'g-. 



If a membrane be present, the ratio of solids not fat to water 

 in cream should differ from the ratio found in milk (except in 

 the case that the ratio of solids to water in the membrane is the 

 same as that in milk) ; the author has shown, and is confirmed 

 by Smith and Leonard, that the ratio remains the same. 



The experiments of Storch and Bechamp on the mixing of 

 ether with milk are capable of an explanation quite different 

 from that which they attach to it when the laws governing the 

 distribution of a substance between two immiscible solvents are 

 taken into account. 'W'e may regard milk as a mixture of an 

 aqueous solution with a large number of fat globules ; on gently 

 shaking up with ether it is evident that very few, if any, of the 

 fat globules come into contact with the ether, but only with an 

 aqueous solution of ether. According to the law, the ether 

 should distribute itself between the fat and the aqueous solution 

 m proportion to the solubility in each ; if the fat is liquid we 

 should expect a large proportion of the ether to pass into the 

 globules, and they would naturally swell ; if, on the other hand, 

 the fat IS solid we would not expect it to take up any appreciable 

 proportion of ether, and the globules would remain the same 

 size. In neither case would any appreciable amount of fat pass 

 into the excess of ether which separates, as fat is very little 

 soluble in an aqueous solution of ether. 



Bechamp used milk which had not been strongh- cooled, but 



