328 SUGAR DESTRUCTION IN THE ECONOMY 



yeast Stoklasa and his collaborators succeeded (by precipi- 

 tating expressed juices by alcoholic ether and rapidly drying 

 the precipitate) in obtaining zymases from beets, potatoes, 

 peas and green types of plants, i.e., enzymes capable of in- 

 ducing an active fermentation of sugar into alcohol and car- 

 bonic acid in complete absence of microorganisms. 1 The 

 studies of Palladin and Kostytschew mark a further step, 

 showing that the anasrobic respiration of plants is appar- 

 ently at least in part an alcohol fermentation which inde- 

 pendently of the life of the cells takes place from the influ- 

 ence of enzymes even after the cells have been killed by 

 freezing. Besides the zymases, according to Stoklasa there 

 are held to be also "lactolases" concerned in the anaerobic 

 plant respiration, which give rise to formation of lactic acid. 

 The related older view, that a molecule of sugar is first 

 separated into two molecules of lactic acid and these later 

 fermented into alcohol and carbonic acid, can no longer be 

 regarded as correct from the modern viewpoint of the fer- 

 mentation theory. However, lactic acid can originate from 

 labile intermediate products through transposition proc- 

 esses. In the later stages of the fermentation process the 

 alcohol fermentation (the zymase being injured by the ad- 

 vancing acidity) may lag behind the lactic acid fermenta- 

 tion, and in still later phases the latter may in turn be 

 limited by a butyric acid fermentation. 



Supposed Occurrence of Zymases in Animal Tissues. 

 There is thus no ground for question as to the occurrence 

 of an alcohol fermentation in the anaerobic respiration of 

 plants. Stoklasa, however, believed his findings applicable 

 to the field of the animal economy, and thought that he could 

 recover zymases from all sorts of tissue (muscle, liver, pan- 

 creas, leucocytes, etc.). 2 These latter discoveries, which 

 were subjected to control tests by many authors, have, how- 

 literature upon the Zymases of Higher Plants: C. Oppenheimer, Die 

 Fermente, 3d ed., 460-474, 1910. 



*Cf. Literature: E. Abderhalden, Lehrb. d. physiol. Chem., 2d ed., 89, 1909. 



