200 



NORMAL MILK : ITS ADULTERATIONS, ETC. 



as it is lield by a great force, and acts as though separated by 

 a semi-permeable membrane, through which the dissolved 

 solids must pass by osmose. As the milk is usually diluted 

 with cold water, this process of osmose takes a considerable 

 time, and the whole of the milk-sugar is not obtained in solution, 

 but a portion is taken down by the fat globules, when they are 

 removed previous to the estimation of the milk-sugar. The 

 same cause can be assigned to the fact that the fat globules in 

 diluted condensed milk rise with such extreme slowness ; a dense 

 layer round the globules increases its mean density, and makes 

 this nearly approach the density of the serum. 



Dilution. — The directions on the label of sweetened condensed 

 milk are often somewhat misleading. For some purposes — e.g., 

 for infant feeding — the directions given are to dilute with five 

 or even seven parts of water. Supposing that these dilutions are 

 performed by volume, the composition will be as follows : — 



TABLE LII. 



Compared with the average composition of human milk 

 which is 



Fat, 

 Sugar, 



3-3 



6-8 



Protein, 

 Ash, . 



1-5 



0-2 



we see that there is a serious deficiency of fat, especially in the 

 diluted condensed skim milk, and a great excess of total sugar. 



Food Value. — Riibners has stated that as a food 2'43 parts of 

 sugar are equal to 1 part of fat. Calculating the value of fat as 

 sugar by this factor, we get the following values for the food 



value of fat and sugar : — 



Condensed Whole Milk. 



Condensed Skim Milk. 



Human Milk. 

 14-82 



With 5 

 Volumes. 



14-61 



With 7 

 Volumes. 



10-96 



with 5 

 Volumes. 



12-34 



With 7 

 Volumes. 



9 23 



Only in the case of the condensed whole milk diluted with 



