20 

 Snyder also pointed out clearly that, 



rule for t v >e temperature coefficient of chemical reaction to 

 vary with temperature, variation should be expected in physiolo- 

 gical processes. 



Li-yinp-ston^l pointeo out that the temperature coeffi- 

 cient of the growth rates of maise seedlirps, as determined by 

 Lehenbauer (1914), could be regarded as following the van ' t 

 Hoff rule, as cemmonly understood, only for a very limited ranee 



of temperatures. 



22 



The data of Miss Leiteh's paper giYing the results 



of carefully controlled experiments on the effect of tempera- 

 ture on the rate of growth of pea seedlings show that the tem- 

 perature coefficient varies quits regularly from a high tc a 



lew value passing from 3 tc 2 between 10 and 29°c. 



23 



Rahn taking his data from experiments of Marshall 



Ward on the rate of development of Bacillus ramosus and 



£C Snyder, Chas. T>. , on the meaning of variationin the magni- 

 tude of temperature coefficients of Physiclcgical processes. 

 Amer. Jour. Physiol. 2h : 167 - 175. 1911. 



Livingston, B. IS., Physiological temperature indices for 

 the study of plant growth in relation tc climatic conditions - 

 Physiclcgical Researches . 1 : 399 - 420. 1916. 



Leitch, Miss I., Some experiments on t>>e influence of 

 temperature on the rate of growth in Pi sum, sa tivum. Am. Bet. 

 30 : 25 - 46. 1916. 



23 



Rdiin, Otto, Der linfluse der Temperatur und der Gift auf 



Fnzywwirkung, Garung and Wachstum. Der Rioeh. Zeitsch. 

 72 : 351 - 3 r '7, 1916. 



24 



Ward, Marshall, On the bic leery of Bacillus ramo sus. 



Proc. Roy Sol. London. 56: 265 -468. 1695. 



