480 FATE OF BODY-FOREIGN SUBSTANCES 



by lipases 67 may be classed here. Observations upon the 

 behavior of stereoisomeric substances in metabolism have 

 been made in case of tartaric acids, 68 arabinoses, 69 , man- 

 noses, 70 methylgluco sides, 71 and monoaminoacids. 72 Par- 

 ticularly in the case of these last (as leucin, tyrosin, aspara- 

 ginic acid and glutaminic acid) the important point was de- 

 veloped that after introduction of these racemic compounds 

 the particular components which occur naturally in animal 

 protein readily underwent combustion, while the body- 

 foreign components almost completely passed out into the 

 urine of the experiment animal. Even the two stereoiso- 

 meric methylglucosides behave very differently in the body ; 

 and the same is true of isomeric forms of sugar (it may be 

 recalled how much more readily glucose is assimilated than 

 galactose). On the other hand, there is no apparent differ- 

 ence between 8- and A-tartaric acid; in both cases racemic 

 acid is eliminated in the urine in unchanged, inactive form. 

 That the system is also able to bring about changes in stereo- 

 chemic configuration is evidenced by the conversion of laevu- 

 lose into dextrose by the diabetic subject, and by the trans- 

 formation of dextrose into galactose in the mammary gland. 

 The name " stereokinases" has been proposed for the hypo- 

 thetical ferments supposed to bring such conversions about. 

 Here, then, is the end of today's discussion; and this is 

 probably well, as the author cannot but fear that the concen- 

 tration of so many formulae and dry chemical facts in such 

 brief outline must decidedly test his hearer's patience. It is 

 indeed a rigid and peculiar material with which this lecture 

 has had to deal, and yet it is well adapted to be shaped into 

 beautiful plastic forms by the hands of one who applies him- 



87 Dakin, Neuberg and Rosenberg. 



"Brion ( Hof meister's Lab.), Zeitschr. f. physiol. Chem., 25, 282, 1898; 

 Neuberg and Saneyoshi, Biochem. Zeitschr., 36, 32, 1911. 



w C. Neuberg and Wohlgemuth, Zeitschr. f. physiol. Chem., 35, 41, 1902. 

 70 C. Neuberg and P. Mayer, Zeitschr. f. physiol. Chem., 37, 530, 1903. 

 T1 S. Lang, Zeitschr. f. klin. Med., 55, 1904. 

 n J. Wohlgemuth, Ber. d. deutsch. chem. Ges., 38, 2064, 1905. 



