THE INFLUENCE OF PHYSICAL FACTORS 



TABLE X. MG. CO., PER KILOGRAM AND HOUR. 



The results have been summarized by Tigerstedt [W.] in the curves, 

 fig. 22. Vernon himself concluded from the observations that the 

 respiratory exchange might remain practically constant over a con- 

 siderable range of temperatures (in the earth-worm for instance between 

 10 and 20), and that the cold-blooded animals possessed some nervous 

 mechanism by which their heat production could be regulated. There 

 is no reason to believe, however, that the deviations from a regular 

 increase with the temperature are anything but accidental and due to 

 the imperfect control over the conditions other than temperature in 

 Vernon's experiments. This is shown by the discrepancy between 

 Vernon's two series on Rana temporaria and by the fact that Kono- 

 packi failed to find in the earth-worm a'ny indication of a constant 

 metabolism between I o and 20. 



Martin's observations on Cyclodes gigas are summarized as 

 follows : 



TABLE XI. 



