219 



bodies contained in the cells of living organisms, with the molcml. > 

 of both active components. Thus the different action of the dextro- 

 and laevogyrate asparagines on the tongue, would be caused by 

 the clill'i rent chemical action of both antipodes upon an asymm< tin 

 substance present in the tissue of the gustatory nerve. 



The living organism thus uses the one component of the external- 

 ly compensated mixture or compound, because its physiological 

 action has been adapted to a special nutriment; and to the same 

 cause must also be attributed the different action on the human 

 body of nicotines, atr opines, and adrenalines which have another 

 configuration than the natural products. 



These views have become most probable, since Buchner 1 ) proved 

 that from yeast-cells by grinding and crushing them with sand, 

 after filtration a clear juice could be obtained from which a special 

 ferment, zymase, could be isolated, which produces fermentation 

 as well as the living cells themselves, and that a second sugar-inverting 

 ferment, invertase, known even then, is also present in the cells. As 

 zymase and invertase are life-less chemical substances, the view that 

 the special phenomena of fermentation are not directly connected 

 with the life-process itself, but can be produced by such charac- 

 teristic substances present in the cells, has now become certain. 



Fischer 2 ) confirmed that x-methyl-glycoside is decomposed by 

 invertase, while @-methyl-glycoside is not ; with emulsine however just 

 the reverse occurs. The enzyme thus has undoubtedly a "selective" 

 action, in the same way as this was formerly stated in the case of 

 living organisms. This apparently selective action must most 

 probably also be referred to a great difference in the velocity of 

 action, when several enzymes are made use of for the attack of 

 the same kind of substances. 



Dak in 3 ) found that /^handed benzyl-mandelic ether is much 

 more rapidly hydrolysed by lipase (from the liver), than the dextro- 

 gyratory antipode, and that in general the ethers of optically active 



1) E. Buchner, Ber. d. d. Chem. Ges. 80. 117, 1110, 2668. (1897); 81. 209, 

 568. (1898); 33. 3307, 3311. (1900); E. Buchner and R. Rapp, ibid. 81. 1084, 

 1090. (1898) ;32. 127, 2086. (1899) ; 34. 1523. 1901); E. Buchner and A. Spitta, 

 ibid. 85. 1703. (1902); E. Buchner and W. Antoni, Zeits. f. physiol. Chem. 

 44. 206. (1905); 46. 136. (1905); etc. 



2) E. Fischer, Ber. d. d. Chem. Ges. 27. 2985, 3230, 3479. (1894); 28. 1429, 

 1508, 3031. (1895). 



3) H. D. Dakin, Journ. of Physiol. 80. 253. (1904); 82. 199. (1905); cf. also: 

 A. Mac Kenzie and A. Harden, Proceed. Chem. Soc. London, 19. 48. (1903). 



