COMPARED WITH STARCH. 71 



we may conclude, with some degree of probability, that 

 its elements, in the peculiar arrangement according to 

 which they are united, are held together with a stronger 

 force than the elements of the different kinds of sugar. 



There is, however, a certain relation between gum 

 and sugar of milk, since both of them, when treated 

 with nitric acid, yield the same oxidized product, name- 

 ly, mucic acid, which cannot under the same circum- 

 stances, be formed from any of the other kinds of 

 sugar. 



In order to show more distinctly the similarity of 

 composition in these different substances, which per- 

 form so important a part in the nutritive process of the 

 graminivora, let us represent one equivalent of carbon 

 by C (= 75-8), and one equivalent of water by aqua 

 (== 112-4), we shall then have for the composition of 

 these substances the following expressions : 



Starch . . . . s= 12 C -f 10 aqua. 



Cane Sugar . = 12 C + 10 aqua -j- 1 aqua. 



Gum = 12 C -|- 10 aqua -{- 1 aqua. 



Sugar of milk = 12 C -f 10 aqua -f- 2 aqua. 

 Grape Sugar = 12 C -j- 10 aqua + 4 aqua. 



For the same number of equivalents of carbon, starch 

 contains 10 equivalents, cane-sugar and gum 11 equiva- 

 lents, sugar of milk 12 equivalents, and grape-sugar 14 

 equivalents, of water, or the elements of water. 



XIV. In these different substances, some one of 

 which is never wanting in the food of the graminivora, 

 there is added to the nitrogenized constituents of this 

 food, to the vegetable albumen, fibrine, and caseine, 



