92 PLANT RESPIRATION 



labile, easily oxidised substances which then fall before a vital 

 combustion. In later work Kostychev has sought to confirm 

 this theory experimentally. In the first place he has shown 

 that ethyl alcohol is oxidised by seed-plants with difficulty or 

 not at all. Secondly, he has called particular attention to 

 the surprisingly strong stimulation of oxygen respiration by 

 means of fermented sugar solutions. ^ These results have already 

 been mentioned. To be sure, they yield no direct evidence 

 that it is particularly the intermediate products of alcoholic 

 fermentation which are burned in normal respiration but they 

 could be interpreted in the sense suggested. On the other hand 

 Kostychev has shown- that fermented solutions contain sub- 

 stances which are completely burned under the influence of 

 the oxidising enzymes of seed-plants. Yet the same oxidising 

 enzymes are unable to form CO2 from grape sugar. All these 

 experiments will be discussed later. 



3. THE LATEST OBJECTIONS TO THE THEORY OF THE CON- 

 NECTION OF ANAEROBIC WITH NORMAL RESPIRATION 



From the above statement it is clear that the following facts 

 can be cited in favor of the theory of connection. 



1. The universal dissemination of anaerobic respiration. 

 So far not a single plant has been found which is unable to pro- 

 duce CO2 in the total absence of oxygen [cf. editorial note b 

 above]. Most of these plants live under conditions which 

 preclude an actual anaerobic condition. The supposed impor- 

 tance of anaerobic respiration as a "biological adaptation'' is 

 therefore most questionable. The assumption is much more 

 probable that it represents a normal vital process. 



2. The activity of zymase is unchecked by free access to 

 oxygen. From the subsequent exposition it will be clear that 

 zymase of seed-plants is no exception in this respect.^ The 

 absence of a production of alcohol in the normal hfe of seed- 

 plants is therefore not attributable to the inactivity of the 



' Kostytschew, S. lor., cit.; also Kostytschew, S. und A. Scheloumow. Jahrb. £. wiss. 



Bot. 50: 157. iQii. 



2 Kostytschew, S. Z. f. physiol. Chem. 67: ii6. 1910. 



2 Kostytschew, S. Ber. d. bot. Ges. 22: 207. 1904; Zentralbl. f. Bakt., Parasitenk. u. 

 Infektionskrankh. (II). 13: 490. 1904; Palladin, W. und S. Kostytschew. Z. f. physiol. 

 Chem. 48: 214. 1907. 



