HULK. 97 



Sugar of milk, sometimes called lactine, or lactose, is the 

 most abundant of the solid constituents of the mammary 

 secretion. It is this principle that gives to the milk its 

 peculiar sweetish taste, though this variety of sugar is much 

 less sweet than cane-sugar. The chief peculiarities of milk- 

 sugar are, that it readily undergoes change into lactic acid 

 in the presence of nitrogenized ferments, and takes on .alco- 

 holic fermentation slowly and with difficulty. At one time, 

 indeed, it was supposed that milk-sugar could not be decom- 

 posed into alcohol and carbonic acid; but it is now well 

 established that this change can be induced, the only pecu- 

 liarity being that it takes place very slowly. In some parts 

 of the world, intoxicating drinks are made by the alcoholic 

 fermentation of milk. Milk-sugar is composed of C ia H w O ia 

 and responds to the ordinary tests for the animal varieties 

 of sugar. 



A consideration of the nutritive action of the fatty and 

 saccharine constituents of milk belongs properly to the sub- 

 jects of alimentation and nutrition. It may be stated here, 

 however, that these principles seem to be as necessary to the 

 nutrition of the child as the nitrogenized principles ; though 

 the precise manner in which they affect the development 

 and regeneration of the tissues has not been ascertained. 



Inorganic Constituents of Milk. It is probable that 

 many inorganic principles exist in the milk which are not 

 given in the table ; and the separation of these principles 

 from their combinations with organic matters is one of the 

 most difficult problems in physiological chemistry. This 

 must be the case, for during the first months of extra-uterine 



nalen der Chemie und Pharmatie, Heidelberg, 1842, B. xlii., S. 70. The above 

 is an approximative estimate of the proportions of the various fatty constituents 

 of butter, deduced from the quantities of fatty acids 'obtained. Bromeis, like 

 many chemists of that day, supposed that the neutral fats were composed of 

 the fatty acids combined with glycerine, or the oxide of glycile. It is now gen- 

 erally admitted that the fatty acids and glycerine are formed by actual decom- 

 position, and do not exist in combination in the neutral fats. 

 V 



