84 ORIGIN OF FAT IN 



trogenised constituents of plants we draw certain 

 inferences as to the nitrogenised constituents of the 

 blood ; and it is quite in accordance with this, the 

 natural method, that we should seek to establish the 

 relations of those parts of our food which are devoid 

 of nitrogen and those parts of the body which con- 

 tain none of that element. It is impossible to over- 

 look the very intimate connection between them. 



If we compare the composition of sugar of milk, 

 of starch, and of the other varieties of sugar, with 

 that of mutton and beef suet and of human fat, we 

 find that in all of them the proportion of carbon to 

 hydrogen is the same, and that they only differ in 

 that of oxygen. 



According to the analyses of Chevreul, mutton 

 fat, human fat, and hog's lard contain 79 per cent, 

 of carbon to 11*1, 11 '4, and 11 -7 per cent, of hy- 

 drogen respectively. (16) 



Starch contains 44*91 carbon to 6'11 hydrogen 

 Gum and sugar 42-58 to 6'37 ditto. (17) 



It is obvious that these numbers, representing 

 the relative proportions of carbon and hydrogen in 

 starch, gum, and sugar, are in the same ratio as the 

 carbon and hydrogen in the different kinds of fat ; for 



44-91 : 6-11 = 79 : 10'99 

 42-58 : 6-37 = 79 : 11-80 



From which it follows, that sugar, starch, and gum, 

 by the mere separation of a part of their oxygen, 

 may pass into fat, or at least into a substance having 

 exactly the composition of fat. If from the formula 



