CELL SIZE AND METABOLIC ACTIVITY IN AMPHIBIA. 375 



TABLE IX. 



RED BLOOD CELL SIZE AND CARBON DIOXIDE PRODUCTION OF INDIVIDUALS 



WITH COMPARABLE WEIGHT. 



The result- recorded in Tables \ III. and IX. and in Chart 4 

 furni-li ronrlu-ive evidence that there is a correlation between the 

 degree >t art ivity of a species as determined by its carbon dioxide 

 output and the size of its red blood cells. The physiological 

 < -ity for -uch a correlation lies in the necessity for haxing 

 Miiln init Mirl'are to allow for the exchanges which take place 

 between Mirfare and interior. If the exchange is rapid, tin- 

 surface nuist be large, and this enlargement of surface is brought 

 about by having the mass divided into smaller packets. 



VII. SUMMARY AND CONCLUSIONS. 



1. Oil size has been measured in a number of species of 

 Amphibia by measuring the dimensions and computing the an-a 

 of red blood corpuscles. Metabolic activity was measured by 

 collecting in barium hydroxide the carbon dioxide produced by 

 tin animal, and computing the carbon dioxide in milligrams per 

 gram of body \\right per hour. 



2. Comparison of the measurements of red blood corpuscles 

 with meaMin-ineiit-. published by other authors indicates that the 

 iiHM-un IIH nt- obtained by the present writer are too low. The 

 cause "I tln-M- low results is unknown. 



3. C.,iitrol> (in the method used in determining carbon dioxide 

 output indicate that this method was not extremely accurate, but 

 sufficiently so to allow for making comparisons between the 

 animal^ used. The chief sources of error were loss of carbon 

 dioxide due to incomplete absorption, and inability to maintain 

 a constant rate of air flow. Indirect evidence that the method i> 

 approximately correct is obtained by comparing actual results. 



4. There is shown to be a size variation between the corpuscles 



