520 SCIENCE PROGRESS 



on isolation of products of putrefaction, had succeeded in the 

 meantime in obtaining other bodies, such as phenylpropionic 

 acid, phenylacetic acid, parahydroxyphenylpropionic acid, the 

 corresponding acetic acid, etc. ; and Nencki concluded that 

 these various bodies must be derived from three different 

 aromatic bodies obtained by the hydrolysis of proteins. These 

 three parent substances must be phenylaminopropionic acid 

 (phenyl alanine), which had been obtained by Schulze as 

 a protein hydrolysis product, tyrosine, and another body 

 at that time unknown, and having the empirical formula 

 of a skatolaminoacetic acid. He represented the formation of 

 these various putrefaction products from their present sub- 

 stances by the following series of equations : — 



Decomposition products of phenyl aniline. 

 C 6 H 5 • CH 2 • CH • (NH 2 )C0 2 H + H - C 6 H 5 ■ CH 2 ■ CH 2 ■ C0 2 H + NH 3 



Phenyl propionic acid 



C 6 H 5 • CH 3 • CH 2 • C0 2 H + 3 - C 6 H 5 ■ CH 2 ■ CO s H + CO, + H 2 



Phenyl acetic acid 



C 6 H 5 - CH 2 - CO s H + 3 = C 6 H 5 C0 2 H + CO,, + H 2 



Benzoic acid 



and also 



C.Hj'CH/CHCNH^-COjH = C 6 H 5 • CH 2 • CH 2 ■ NH 2 + C0 2 . 



Decomposition products of tyrosine. 

 OH OH 



XH 2 CH(NH,)-CO,H + H 3 " ' s CH a ■ CH 2 - C0 2 H + NH 3 



Parahydroxyphenyl propionic acid. 



OH .OH 



C b H.,< = C 6 H/ + C0 2 + H 2 



CH 2 -CH 2 -CO,H + 3 N CH 2 -COOH 



Parahydroxyphenyl acetic acid. 



