88 THE NITROGENOUS DERIVATIVES OF THE ALBUMINS. 



( 4 II 7 lNII,) 2 .COOH -f 2C 6 H 6 .COOH = C 4 H 7 (NH.C 6 H 5 .CO),.COOH + 2 ILO 

 Ornithin. Benzoic acid. Hippuric acid. 



The amido-acids also are closely related to the biliary acids, as on 

 decomposition with baryta-water, glycocholic acid is decomposed 

 into glycocoll and cholalic acid, as shown in the equation : 



C^Na + H 2 = CH 2 (NH 2 ).COOH -f C 24 I I < > 

 Glycocholic Ulycocoll. (hcl.-'lic 



acid. 



acid- 



Taurocholic acid similarly gives rise to cholalic acid and taurin, 

 which latter can be regarded as amido-isethionic acid that is, as 

 isethionic acid, H(C 2 H 4 .OH)SO 3 , in which the hydroxyl grouj) 

 has been replaced by the amido-radicle : 



C^NO^ + H 2 = C 24 H 40 5 + C 2 H 7 NO 3 S 

 Taurocholic Cholalic Taurin. 



acid. acid. 



After the ingestion of amido-acids, moreover, the corresponding 

 compounds of carbamide, CONH, appear in the urine. These are 

 spoken of as the uramic acids, and comprise methyl-hydantoinic acid, 

 taurocarbamic acid, uramido-benzoic acid, and tyrosin-hyclantoinic 

 acid, or hydantoin-hydroparacumaric acid. They are found after 

 the ingestion of sarcosin or methyl-glycocoll, of taurin, amido- 

 benzoic acid, and tyrosin, respectively. The syntheses which are 

 thus effected may be represented by the equations : 



C 3 H 7 2 -f CONH == C 4 H 8 N 2 3 



Sarcosin Methyl-hydantoinic 



acid. 



C 2 H 7 NS0 3 + CONH == C 3 H 8 N 2 S0 4 



Taurin. Taurocarbamic 



acid. 



C 7 H 7 N0 2 + CX)NH = C 8 H 8 N 2 3 



Amidobenzoic Uramido-benzoic 



acid. acid. 



C 9 H n N0 2 -f CONH = C,oH 10 N 2 3 + H 2 O 

 Tyrosin. Tyrosin hydantoinic 



acid. 



Among the mono-amido acids, finally, which may be formed in 

 the animal body, we must mention cystem, or -amido-thiolactic 

 acid. This is of special interest, as its disulphide cystin is occa- 

 sionally found in human urine, and is then commonly associated 

 with the diamins putrescin and cadaverin. The relation which 

 exists between cystin and cystem is thus similar to that of a mer- 

 captan to its disulphide, and may be represented by the equation : 



H 3 C X /SB. H 3 C X X - K /CH 3 



9 \P/ _L A N/V \f/ _1_ TT n 



>L\ -\- U = XX >U\ -f- 1 2 <J 



H 2 N X \COOH n,W \COOH COOH X NH 2 



Cystem. Cystin. 



Analogous to the synthetic formation of hippuric acid after the 

 ingostion of benzoic acid, we find in dogs and rabbits that following 

 the administration of mono-bromobenzol bromophenyl-mercapturic 



