CHEMICAL BASIS OF THE ANIMAL BODY. 1243 



ther clearly evidenced by the method of its synthetic produc- 

 tion by the action of monochloracetic acid on ammonia: — 



CH 2 (C1) . COOH + 2NH 3 = CH 2 (NH 2 ) . COOH = NH 4 Cl. 



Fig. 201. Glycine Crystals. (After Funke.) 



Preparation. Either synthetically as above, or more usually by 

 the decomposition of hippuric acid by prolonged boiling with hydro- 

 chloric acid, whereby it is split up into glycine and benzoic acid, the 

 latter being separated by chrystallization and shaking up with ether 

 in which glycine is insoluble. 



3. Sarcosine. 



C 3 H 7 N0 2 . [CH 2 . NH (CH 3 ) . COOH]. (Methylglycine.) 



Like glycine in its general chemical properties it further 

 resembles it in that it is never found in the free state as a 

 constituent of the animal body. It is however a substance of 

 considerable interest and importance, not merely on account of 

 its chemical relationship to creatine (see below), but as having 

 been employed in a well-known series of experiments intended 

 to elucidate the probable mode of formation of urea in the body. 



4. Diamido-acetic acid. [CH . (NH 2 ) 2 . COOH]. 



This acid has recently been found among the products of 

 the decomposition of casein by boiling with hydrochloric acid 

 and stannous chloride. 



5. Amido-valerianic acid. [C 4 H 8 (NH 2 ) . COOH]. 



Has been described once as obtained from pancreas tissue or 

 the products of its putrefactive decomposition. Is crystalline, 

 soluble in water and somewhat insoluble in alcohol and ether. 



