58 ON NITROGEN. 



nature, and one, as this article will demon- 

 strate, of the most vital importance in the 

 economy of animal and vegetable life. The 

 process by which vegetables have the power 

 of forming this compound, and the sources 

 from which it is obtained, will now form the 

 subject for our consideration. 



The portion of farinaceous matter in which 

 the nutriment resides, is what is termed the 

 gluten, and it may be easily prepared from 

 wheat flour, by mixing it into a paste, and 

 washing it constantly with water until the 

 water runs away quite transparent. The pure 

 gluten then remains, and when dried, it some- 

 what resembles glue, and is in every respect 

 perfectly analogous to animal gluten. 



This substance has never yet been analyzed 

 with a view to obtain its ultimate constituents; 

 but Dr. Henry, in speaking of it, says, " It 

 closely resembles animal gluten, especially in 

 the large quantity of nitrogen which enters into 

 its composition." It may here be stated that 

 the value and weight of wheat, and all grain 

 depends on the quantity of gluten it contains, 

 the best wheats containing the greatest quan- 

 tity of gluten, and the smallest quantity of 

 starch ; its weight and value as an article of 

 food, depending on the relative proportion of 

 the two ingredients. 



The following tables prepared by Sir H. 

 Davy, give the result of an analysis of various 

 kinds of corn, and they may in some degree as- 



