234 AGRICULTURAL CHEMISTRY 



mixed nitrogenous compounds, and are closely related to 

 both the nitrogenous and non-nitrogenous groups. 



325. Lecithin is a nitrogenous fat. It is soluble in 

 ether, and has many of the characteristics of fats. It 

 contains fatty acids in combination with nitrogenous bases 

 and other bodies. It is present in milk, egg- yolk, and in 

 small amounts in all of the cereals. 



326. Nitrogenous Qlucosides. There are a number 

 of glucosides which contain nitrogenous radicals. These 

 glucosides, when treated with acids, yield glucose and 

 nitrogenous acid products. The nitrogenous glucosides 

 and lecithin may be regarded as compounds which are 

 intermediate in the classification of the organic com- 

 pounds into nitrogenous and non-nitrogenous groups. 



327. General Relationship of the Nitrogenous Or- 

 ganic Compounds. A general relationship exists among 

 the nitrogenous compounds similar to that among 

 the non-nitrogenous (see Section 289). The amides and 

 amines are the simplest in chemical structure of the 

 nitrogenous compounds, while the proteids are the most 

 complex. In plants, the amides are intermediate com- 

 pounds formed in the production of proteids. The proteid 

 molecule contains, with other bodies, amide and fatty acid 

 radicals. Amide products are also obtained from the 

 albuminoids. Thus it appears that the amides and amines 

 form the basal structure of the nitrogenous part of the 

 molecules of proteids, albuminoids, and alkaloids, and 

 these compounds differ from each other chemically, 

 according to the nature and kind of radicals in combi- 

 nation with the different amide and amine compounds. 



