116 HOW CROPS GROW. 



acid, also called glycocoll, has not as yet been found in 

 plants, but exists in the scallop and probably in other 

 shell-fish, and a compound of it, benzoylglycocoll or hip- 

 puric acid, is a nearly constant ingredient of the urine of 

 the horse and other domestic herbivorous animals. 



Betain, or trimethylglycocoll, C 5 H U N0 2 , a crystalliza- 

 ble substance found in beet-juice, stands in close chem- 

 ical relations to amidoacetic acid. 



Amidovaleric acid, CsHnNC^, occurs in ox-pancreas 

 and in young lupin plants. Amidocaproic acid, or 

 Leucin, C 6 H 13 N0 2 , first observed in animals, has lately 

 been discovered in various plants. The same is true 

 of Tyrosin, or oxyphenyl-amidopropionic acid, 

 CsHnNOs, and of phenyl - amidopropionic acid, 

 C 9 H U N0 2 . 



The above amidoacids are readily obtained as productf 

 of decomposition of animal and vegetable albuminoids by 

 the action of hot acids. Amidoacetic acid was thus first 

 obtained from gelatin. Leucin and Tyrosin are com- 

 monly prepared by boiling horn shavings with dilute sul- 

 phuric acid ; they are also formed from vegetable albu- 

 minoids by similar treatment and are final results of the 

 digestion of proto- and deutero-proteoses (hemialbumose) 

 under the action of trypsin and papain. 



Asparagin and Glutamin. These bodies, which are 

 found only in plants, are amides of amidoacids, being de- 

 rived from dibasic acids. Asparagin, the amide of 

 amidosuccinic acid, 



CH(jSTH 2 )COOH 

 CHjCOXH, 



has been found in very many plants, especially in those 

 just sprouted, as in asparagus, peas, beans, etc. Aspara- 

 gin forms white, rhombic crystals, and is very soluble in 

 water. 



Glutamin, the amide of amidoglutaric acid, 



