THE COMPONENTS OF PLANTS AND ANIMALS 37 



The nitrogenous glucosids 

 Alkaloids and organic bases 

 Amino acids and amids 

 Nitrates and ammonium salts 



62. The muscle extractives. The more important nitrog- 

 enous muscle extractives are creatin, creatinin and the purin 

 bases xanthin and hypoxanthin. 



63. Nitrogenous lipoids. As noted (37-39), the lipoid 

 group includes a number of compounds, classed as phosphatids 

 and cerebrosids, which contain a nitrogenous group in combi- 

 nation with fatty acid radicles. The most familiar members of 

 this group are the lecithins. The actual amounts of these sub- 

 stances contained either in the animal or plant are small and 

 their nitrogen does not constitute any important fraction of 

 the total nitrogen of the body or of the feed. 



64. Alkaloids and organic bases. Alkaloids are compara- 

 tively rare in agricultural plants, the seeds of the lupine forming 

 the principal exception. The organic bases, on the other 

 hand, appear to be somewhat widely distributed. In addition 

 to the so-called " hexon bases " arginin, lysin and histidin, de- 

 rived from the proteins and nucleo-proteins, the bases cholin, 

 betain, trigonellin and stachydrin have been found in a variety 

 of plants. 



65. Nitrogenous glucosids. The substances of this group 

 are characteristic of the vegetable kingdom. They contain 

 a variety of nitrogenous compounds coupled with simple sugars. 

 The nitrogenous glucosids do not appear to be especially abun- 

 dant in the ordinary feeding stuffs of domestic animals and 

 where they do occur are distinguished rather by their specific 

 physiological effects than by their nutritive value in the or- 

 dinary sense. E. Schulze l mentions seven bodies of this class 

 which have been found in various plants. 



66. Amino acids and amids. These substances are by far 

 the most abundant forms of non-protein in vegetable materials. 

 The first one to be discovered was asparagin, in 1805, in aspar- 

 agus shoots, and this substance has since been found in a large 

 number of plants or parts of plants. Glutamin, a second 

 amid, is also of frequent occurrence in plants. 



1 Jour. Landw., 52 (1904), 305. 



