§2] 



EFFECT ON GENERAL FUNCTIONS 



223 



Likewise Moissan ('79, p. 296) found that, in the dark, the 

 amount of oxygen absorbed by a branch of certain plants varied 

 with the temperature. Thus there was absorbed per hour by 



Pinus pinaster (30 grammes) 



Agave americana (70 grammes) 



at 0° C, 0.32 c.c. 

 at 13°, 



I at 15°, 

 J at 11° C, 

 1 at 40°, 



1.30 c.c. 

 1.90 c.c. 

 0.54 c.c. 

 6.56 c.c. 



These experiments serve to show clearly that in plants more 

 oxygen is absorbed as the temperature is raised to the optimum. 



The same result is obtained from animals also. Thus Tee- 

 viKANUS ('31, p. 23) found that the honey bee Apis mellifica 

 absorbed at 14° C. 1.35 Paris cubic inches, and at 27.5°, 2.77 

 cubic inches of oxygen. At the higher temperatures the bee 

 was very active, so that the result seems here somewhat com- 

 plicated by the increased muscular activity accompanying a 

 higher temperature, which invokes a more rapid respiration. 

 Nevertheless, the phenomena of increased oxygen absorption 

 with higher temperature are fundamentally the same in plants 

 and animals. 



Turning now to the process of excretion, it appears that the 

 amount of COg evolved by seedlings varies with the tempera- 

 ture. On this point we have data by Deheeain and Moissak 

 ('74, p. 327), RiscHAWi ('77), and others. Dbheeain and 

 MoissAN experimented with leaves of tobacco kept in the 

 dark. The same plant was used throughout the experiment, 

 and it remained throughout in good condition. In the follow- 

 ing table the temperatures are given in the first column, and, 

 in the second, the number of grammes of COj produced per 

 100 grammes of leaves : — 



When plotted (with the temperatures as abscissae) the relation 

 between temperature and weight of CO2 produced is expressed 



