OXYGEN RESPIRATION 



The determinations of Bonnier^ showed an even greater 

 heat production as it corresponds to the total oxidation of 

 sugar (respiration is, as we know, not the only source of energy 

 of living cells). The more recent exact studies of L. C. Doyer- 

 yielded still other results. It was shown that, during the 

 periods in which intense growth and formative processes are 

 taking place, as is the case for example during the early days of 

 seed germination, the greater part of the respiratory energy is 

 used for vital needs and only a little energy vanishes in the 

 form of heat. E.g., 



Wheat Seedlings 



It is evident that on the second day of germination only 12% 

 of the total energy is released as heat. The greater part of the 

 chemical energy is used in the formative processes. Even on the 

 sixth day only half of the total energy could be measured as heat. 



According to the latest determinations, molds Hberate the 

 greater part of the respiratory energy as heat.^ In this case 

 old fungus mats were employed for the experiments. Probably 

 young, vigorously growing fungus mats would yield entirely 

 different results. 



4. THE INFLUENCE OF VARIOUS EXTERNAL FACTORS ON 



OXYGEN RESPIRATION 



It was mentioned above that respiration as a constant feature 

 of Hfe is a criterion of the living condition of the cells. The 

 modification of the respiratory process under the influence of 

 external factors might often serve as a direct measure of the 



191 4; Recuil des trav. bot. 



1 Bonnier, G. Ann. sci. nat. (VII) 18: i. 1893. 

 2Doyer, L. C. Medd. Akad. Wet. Amsterdam 17: 62. 

 neerland 12: 372. IQIS- 



3 MoUiard, M. Compt. rend, des seances de la soc. de biol. 87: 219- 1922. 



