272 THE URINE. 



to 40 per cent, of the total amount, and it is known that in such 

 cases tatirocarbaminic acid is constantly present. Its formation may 

 be represented by the equation : 



/C 2 



SO/ 

 \OH 



C 2 H 4 .NH, xj / 



+ CO/ = CO/ 



\NH 2 \NH.C 2 H 4 .S0 2 .O.NH 4 . 



Taurin. Urea. Ammonium taurocarbamate. 



In all probability this synthesis is effected in the kidneys. In 

 rabbits, on the other hand, taurin is largely oxidized to sulphuric 

 acid, while a small portion appears as thiosulphuric acid. Of the 

 origin of taurin, as I have stated, nothing definite is known. 



Cystein, on the other hand, is apparently derived from the 

 loosely combined sulphur of the albumins, and probably represents 

 an intermediary product of oxidation, which is normally further 

 oxidized to sulphuric acid. Traces, however, apparently escape this 

 destruction and normally appear in the urine. As a matter of fact, 

 cystei'n is not readily oxidized within the body, and in dogs one- 

 third of the ingested amount reappears as such. Following the 

 administration of chlorine, bromine, or iodine substitution-products 

 of the benzols, moreover, a diminished elimination of sulphuric acid 

 occurs, and in place of this we meet with a conjugate glucuronate, 

 which contains the greater portion of the lacking sulphur. The 

 product which thus results can readily be decomposed, with the 

 formation of glucuronic acid and chlorophenyl-mercapturic acid, 

 which latter manifestly contains the cystei'n group, as is seen from 

 the formula? : 



CH 3 



8EK I C 6 H 4 C1.S 



COOH 



On decomposition it yields acetic acid and chlorophenyl-cyste'in, 

 as shown in the equation : 



CH 3 CH 3 



CH 3 .CO.NH V | NH 2X | 



>C + H 2 O == CH 3 .COOH -f >C 



C 6 H 4 CLS/ | C 6 H 4 C1.S/ | 



COOH 'COOH 



The amount of cystei'n which is normally present in the urine 

 probably does not exceed 0.015 gramme in the twenty-four hours. 

 Larger quantities are found in phosphorus poisoning, which further 

 suggests the occurrence of the substance as an intermediary product 

 in the normal metabolism of the organic sulphur, as we know that 

 in such cases the oxidation-processes of the body, as a whole, are 

 much impaired. 



