Ill] 



OF TEMPERATURE COEFFICIENTS 



225 



illustrations, however, among animals, in which we may study the 

 temperature-coefficient under circumstances where, though the 

 phenomenon is always complicated, true metabohc growth or 

 chemical combination plays a larger role. Thus Mile. Maltaux and 

 Professor Massart* have studied the rate of division in a certain 

 flagellate, Chilomonas paramoecium, and found the process to take 

 20 



per 

 hour 



20 



1-8 



1-6 



1-4 



1-2 



1-0 



•8 



•6 



•4 



•2 



4° 8° 1 2° 1 6° 20° 24° ^ 28° 32° ^ 



Fig, 64. Relation of rate of growth to temperature in rootlets of 

 pea. From Miss I. Leitch's data. 



29 minutes at 15° C, 12 at 25°, and only 5 minutes at 35° C. These 

 velocities are in the ratio of 1 : 24: 5-76, which ratio corresponds 

 precisely to a temperature-coefficient of 24 for each rise of 10°, or 

 about 1-092 for each degree centigrade, precisely the 'Same as we 

 have found for the growth of the pea. 



By means of this principle we may sometimes throw hght on 

 apparently compUcated experiments. For instance. Fig. 65 is an 



* Rec. de VInst. Bot. de Brzizelles, vi, 1906. 



