ALBUMINS OR PROTEINS. 249 



when sodium cholate, that is, the other component of taurocholic acid, 

 was added at the same time with the cysteine. Wohlgemuth l confirmed 

 these experiments, and showed with rabbits that the amount of sulphur 

 in the bile and the sulphur content of the liver increased with the admin- 

 istration of cysteine alone. 



We know nothing definite concerning the further history of tauro- 

 cholic acid or of the taurine contained in its molecule. Salkowski 2 found 

 that, after the administration of taurine to human beings and dogs, a 

 part of this taurine and a substituted urea, 



/NH 2 

 C=0 

 \ /H 



N \ CH 2 CH 2 . S0 3 H 

 appeared in the urine. 



Almost all of the sulphur of the taurine reappears in the urine as sul- 

 phuric and sulphurous acids, when fed to a rabbit. 



Salkowski could not detect any increased elimination of sulphuric acid 

 nor of sulphurous acid, after taurine had been fed to human beings 

 and dogs. Cysteine increases the elimination of sulphuric acid in the 

 urine of human beings and dogs. 3 The same also is observed in the case 

 of rabbits, while here salts of hyposulphurous acid are found in addition. 

 We will add that thiosulphuric acid has been found in the urine of cats 

 and dogs. 



It has been shown recently 4 that cystine, in the form of polypeptides, is 

 apparently decomposed during metabolism in the same manner as when 

 cystine itself is administered. It is interesting to note that in these experi- 

 ments there was a distinct increase in the oxidized sulphur of the urine 

 corresponding to the duration of the experiment. The urine always 

 contains a part of the sulphur in an unoxidized form. This portion is 

 also called " neutral " sulphur. Its amount varies and to some extent is 

 directly related to the oxidized sulphur. 



It is at present impossible to give a clear outline of the relations of the 

 components containing sulphur of the urine to albumin or its cleavage- 

 products, because we are not yet able to recognize all the constituents of 

 proteins which contain sulphur. We can only consider the fact as settled 

 that the sulphur in the cystine administered to an animal organism largely 

 reappears in an oxidized form in the urine; in fact, as sulphuric acid. 

 There is no doubt but that cystine is also formed during a normal disinte- 



1 Z. physiol. Chem. 40, 81 (1903). 



2 Virchow's Arch. 58, 460 (1873). 



3 Cf. E. Goldmann: Z. physiol. Chem. 9, 260 (1885). C. H. Rothera: J. Physiology, 

 32, 175 (1905). L. Blum: Hofmeister's Beit. 5, 1 (1903). 



4 E. Abderhalden and F. Samuely: Z. physiol. Chem. 46, 187 (1905). 



