INFLUENCE OF TEMPERATURE UPON LIFE-PROCESSES 423 



characteristic distinguished the temperature-coefficient of the time 

 consumed in the pupal stage of development: 



Temperature. 

 13.45 . 

 15.55 . 

 17.0 

 18.8 

 20.9 

 23.65 . 

 27.25 . 

 32.7 . 

 32.95 



Hours spent in pupal 

 condition. 



Temperature-coefficient 

 per 10 C. 



1116. 

 742. 

 593. 

 439.6 

 320. 

 234.1 

 172.5 

 137.9 

 134.25 



6.2 



4.9 



2.6 



1.5 



We may infer that the time spent in the pupal stage depends upon 

 the extent of tissue-oxidation which has occurred. 



By employing curarized frogs and decerebrated turtles Krogh was 

 also enabled to investigate the effect of temperature upon the Tissue - 

 respiration of these animals. The values of the coefficients obtained 

 lay between 2 and 4, but the values were not found to be so greatly 

 affected by the position on the temperature-scale of the temperature- 

 range employed as in the case of the insect-larvae. 



The influence of temperature upon the Rate of Development of 

 organisms is again of a similar character. Thus Hertwig has investi- 

 gated the influence of temperature upon the time taken to reach seven 

 different arbitrarily chosen stages of development of the larvae of a 

 frog, Rana fusca. The following were the results obtained: 



We have seen that the rate of development in the pupal stage of 

 insects and the rapidity of their basal metabolism are very similarly 

 influenced by temperature, so that we may infer with probability that 

 oxidations determine the duration of this period of development. This 

 is not the case in the earliest stages of development, however, for 

 Loeb and Wasteneys have investigated the influence of temperature 

 upon the time which elapses between insemination and the first cell- 

 division in sea-urchin eggs and have compared with this the effect of 

 the same temperatures upon the oxygen-consumption of the eggs. 

 The two sets of temperature-coefficients are unmistakably of the 

 magnitude of the coefficients of chemical reactions, but they are very 

 diversely affected by alteration of the position of the temperature- 

 range, as the following figures show: 



