COMPARED WITH STARCH. 73 



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 oxidised pro- 

 duct, namely, mucic acid, which cannot, under the 

 same circumstances, be formed from any of the other 

 kinds of sugar. 



In order to shew 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 com- 

 position of these substances the following expres- 

 sions : — 



Starch = 12C + 10aqua. 



Cane Sugar... = 12 C + 10 aqua+l aqua. 



Gum = 12 C+ 10 aqua+l aqua. 



Sugar of milk = 12 C + 10 aqua 4" 2 aqua. 

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



For the same number of equivalents of carbon, 

 starch contains 10 equivalents, cane-sugar and gum 

 11 equivalents, sugar of milk 12 equivalents, and 

 grape-sugar 14 equivalents, of water, or the ele- 

 ments of water. 



