■ THE CONNECTION OF OXYGEN RESPIRATION 9$ 



of the combustion of the intermediate products of fermentation 

 appears to be unknown to Maquenne and Demoussy. 



Boysen-Jensen^ emphasizes the fact that in his experiments 

 with some plants the value of I/N fell below l^. The author 

 assumes that in the case of plants which exhibit a more or less 

 intensive anaerobic respiration this is really connected with the 

 normal respiration and facilitates the complete oxidation of 

 sugar. On the contrary, plants which exhibit a very weak 

 anaerobic respiration present difficulties to the theory of con- 

 nection, in the opinion of Boysen- Jensen. That is to say, if the 

 total amount of the sugar used in respiration were first handled 

 by enzymes of fermentation the latter must complete the fer- 

 mentation of the sugar in the absence of oxygen and thereby 

 liberate }i the amount of CO2 which is set free by the total 

 combustion of sugar. 



CgHioOe = 2 CO. + 2CH3— CHoOH (Fermentation) 

 CeHioOe + 6O2 - 6C0.> + 6H0O (Combustion). 



It has already been pointed out that the determinations of 

 I/N are of no great significance because the intensity of the 

 anaerobic respiration is affected by the degree of the poisoning. 

 Boysen- Jensen himself also calls special attention to the fact 

 that especially with plants which gave small values of I/N in 

 his experiments the anaerobic production of CO2 decreased 

 from hour to hour. Thus it appears that the author contradicts 

 himself when he writes: "Indeed there is the possibility that 

 the intramolecular respiration is insignificant with plants of 

 this group because the plants are injured during the anaerobio- 

 sis. Against this is the fact that the plants recover after a 

 short anaerobiosis " (page 29). However, on page 8 of his 

 interesting paper Boy sen- Jensen writes to the effect that "the 

 value of this quotient (I/N) is very problematical" and later 

 on continues: "As we shall see later the quantity of carbon 

 dioxide formed during anaerobiosis is not constant for various 

 plant material but decreases from hour to hour. The value 

 of the quotient in question changes very rapidly with the dura- 

 tion of the anaerobiosis." 



' Boysen-Jensen, p. Biol. Meddel. udgivne af det danske videnskab. selskab. 4 : i- 1923. 



