514 



ON INCREASE IN SIZE 



[PT. Ill 



Table 72. 

 Temperature coefficients of insect development. 



fasciata) 



Bachmetiev made some experiments like those of Sanderson 

 and Peairs, and Kanitz reviewed all the older literature in 191 5. 

 Kanitz also suggested that the variations found in the pregnancy 

 time of mammals, and especially man, might be related to the 

 differing body-temperature in individuals, for 2° at a Q^iq of 2-5 

 would in man make a difference of 10 days. This notion was sup- 

 ported by O. Wellmann, who went through the statistics of preg- 

 nancy time in mares and found that, while the average was 326 days 

 from July to September, it was 343 days from March to May. Since 

 the researches of Cobelli; Vos; Congdon; and Sumner have all shown 

 that the body-temperature is raised to a slight degree when the 

 environing atmosphere is warm, the gestation time might very 

 well be expected to show the seasonal rise and fall which it 

 actually does. Vicarelli's thermometric observations support Kanitz's 

 theory. 



