THE MILK OF THE ASS. 405 



The following is the composition given by various authorities : — 

 TABLE CXXIII. 



Pizzi has shown that the fat is somewhat low in volatile acids 

 (see p. 391). 



The author has prepared the .suj^ar and finds that it has a 

 specific rotatory power [a]o = 52 '5' (for hydrated sugar), a 

 birotation ratio of 1 '6, and corresponds in every particular 

 with milk-sugar. 



The milk has a very feeble alkaline reaction ; rennet produces 

 a vpi-y soft curd after a long time, and acids ^ive a finely divided 

 precipitate. On boiling, it has a tendency to curdle and deposit 

 flakes (coagulated albumin ?). It has a white colour and a suect 

 taste. 



The aldehyde figure multiplied by 0'154 j^ive.s a close approxi- 

 mation to the proteins. 



Milk as a Food and a Medicine. — In considering the food value 

 of mdk, two points must be borne in mind ; first, its value in 

 repairing the waste of the tissues ; and second, its value as a 

 source of energy. A.s a food for infants it is required not only to 

 repair waste of tissues, but to actually build them up. 



Composition of Constituents. — The following table gives 

 the percentage composition of the three main constituents of 

 milk : — 



TABLE CXXIV. 



Fut, 



Sugar. 



Prutriii, 



Carbon. Hydrogen. ' Oxygen. ' Nitrogen. 



Per cent. 



15-77 



It is seen that fat is the richest in carbon and hydrogen, protein 

 ne.\t. while sugar occupies the lowest place. Neither fat nor 



