MECHANISM OF RESPIRATION 159 



so described, amongst them being phosphates * which are im- 

 portant accelerators in zymase action.f 



Palladin looks upon lipoids as being of the nature of 

 coenzymes, since the more they are extracted from the plant 

 tissue, the greater is the reduction in the intensity of respira- 

 tion although not in an exact proportion. J 



Galitsky and Wassiljeff § observed that the addition of 

 boiled water extracts of bean seeds and wheat grains increased 

 the output of carbon dioxide in living and in dead seedlings to 

 a degree depending on the acidity of the culture medium : 

 in neutral cultures the increase reached 117 per cent., whilst 

 in a slightly alkaline medium an increase of 86 per cent, ob- 

 tained as compared with an increase of 60 per cent, in a slightly 

 acid medium. 



CURRENT IDEAS ON THE MECHANISM OF 

 RESPIRATION. 



Modern views on the mechanism of respiration include 

 an anaerobic phase even in organisms which are obligate 

 aerobes. It is therefore desirable to draw attention to the 

 salient phenomena presented in the anaerobic respiration of 

 higher plants, an extravagant method of obtaining energy 

 giving origin to carbon dioxide and ethyl alcohol which, in 

 a sense, is wasted unless further oxidized to carbon dioxide 

 and water.|| 



It has previously been mentioned that the higher plants, 

 although normally aerobic, may be facultatively anaerobic ; 

 the anaerobic respiration of germinating pea seeds, for example, 

 is a commonplace of the laboratory. To take a specific 

 example. Parija f has compared the respiration of the apple 

 fruit in normal air and in an atmosphere of nitrogen. The 

 work of Blackman and Parija on the aerobic respiration of the 



* Iwanoff : " Biochem. Zeitsch.," igio, 25, 171 ; 1911, 32, 74 • Za " 

 leski and Reinhard : id., 1910, 27, 450. 

 f See Vol. I., p. 494. 



I Palladin : " Ber. dent. bot. Gesells.," 1910, 28, 120. 

 § Galitsky and Wassiljeff : id., 182. 

 || See Kostytschev : " J. Russ. Bot. Soc," 1916, 1, 1S2. 

 1J Parija : " Proc. Roy. Soc," B, 1928, 103, 446. 



