THE CONNECTION OF OXYGEN RESPIRATION 93 



enzymes of fermentation in the presence of oxygen. It is much 

 better to assume that the products of fermentation are burned 

 in the respiratory process. 



3. This assumption is supported by two kinds of facts. In 

 the first place, sugar solutions fermented by yeast stimulate the 

 normal oxygen respiration of plants.^ Secondly, after a tem- 

 porary deprivation of oxygen there follows a powerful increase 

 in the aerobic production of CO2 if the material is not severely 

 poisoned during the anaerobiosis.- 



4. It is a consistent fact that the oxidising enzymes of plants 

 are unable to attack sugar directly but are able to burn to CO2 

 the substances contained in fermented solutions. Hereby the 

 necessity for the anaerobic cleavage of sugar for the normal 

 process of oxygen respiration becomes clear. ^ 



5. Various types of external influences on normal and anaero- 

 bic respiration do not modify the value of I/N. This shows 

 that the aerobic and the anaerobic production of CO2 are 

 influenced in the same way and to the same degree.'* For 

 example, it is worthy of note that, according to Amm, the 

 course of the anaerobic respiration in the germination of seeds 

 may be shown by the same curve of the grand period of respira- 

 tion as the course of oxygen respiration and of growth. Thus 

 it appears that increased respiratory activity requires a corre- 

 sponding increase in the intensity of the first phase of respira- 

 tion. None the less convincing are the results of Morkowin 

 and especially those of Smirnoff. Morkowin has shown that 

 the value of I/N remains unchanged when respiration is stimu- 

 lated by the action of poisons. Smirnoff produced the same 

 effect by wound stimulus. In this connection there is the 

 following circumstance which may be regarded as an unequiv- 

 ocal confirmation of the theory of connection. The stimula- 

 tion of anaerobic respiration by mechanical stimuli is possible 



1 Kostytschew, S. Biochem. Z. 15: 164. 1908; 23: 137- ipog; Ber. d. bot. Ges. 31: 

 422. 432. 1913. 



2Maquenne. Compt. rend. 119: 100, 697. 1894; Palladin, W. Zentralbl. f. Bakt., 

 Parasitenk. u. Infektionskrankh. (II). 11: 146- 1904. 



3 Kostytschew, S. Z. f. physiol. Chem. 67: 116. 1910. 



<Amm. Jahrb. f. wiss. Bot. 25: i. 1893; Palladin, W. Rev. gen. de. bot. 6: 201. 

 1894; Chudiakow, N. Landwirtschaftl. Jahrb. 23: 333- 1894; Morkowin, N. Ber. d. 

 bot. Ges. 21: 72. 1903; Smirnoff. Rev. gen. de bot. 15 : 32. 1903. 



