NITROGENOUS ORGANIC COMPOUNDS OF PLANTS 2 29 



atoms of NH 3 , the product is amidoacetic acid. The 

 amides and amines are sometimes called compound am- 

 monias, and are produced in plants from ammonia during 

 growth, and in animals during the digestion of proteids. 



315. Formation and Occurrence in Plants. The 

 amide and amine compounds in plants are present mainly 

 in the early stages of growth. The young plant takes 

 up from the soil simple nitrogenous compounds, as am- 

 monia, then a chemical change occurs in the tissues of 

 the plant, and as a result, a part or all of the hydrogen 

 of the ammonia is replaced, and an amide is formed. In 

 the study of the composition of proteids (see Section 295) 

 it was stated that the proteid molecule when decomposed 

 yields amide and amine products; consequently it would 

 appear that these compounds are intermediate products 

 in the production of proteids. In the early stages of 

 plant growth, amides are present in greatest abun- 

 dance, but as the plant approaches maturity, they are 

 used for the production of proteids. In clover, for 

 example, 35 per cent, of the total nitrogen is in the form 

 of amides before bloom, while only 12 per cent, is in the 

 same form after bloom. 



316. Formation and Occurrence of Amides in Ani- 

 mals. In the animal body, amides and amines are not 

 formed from ammonium compounds, as in plants, but 

 from proteids. When the proteid molecule is broken up, 

 as in digestion, amides and amines are produced. Urea, 

 an amide, is one of the final products in the digestion of 

 protein, and is excreted from the body in the liquid ex- 

 crements, while amidoacetic acid is excreted with the 



