JANSKY 



is a net to avoid gliding or riding the axle. Running speed was 

 controlled with a Variac to prevent the animals from being car- 

 ried by the wheel and we were thus able to obtain really maximal 

 values. 



HART: Did you keep increasing the speed until they could 

 just maintain that position without being forced? 



JANSKY: Yes, of course they sometimes stopped, but in 

 this case the load touched them and they started again. 



JOHANSEN: When you are comparing metabolic rates in 

 these groups, that is, working and resting animals, it seems 

 to me there will have to be a different insulation in the two. How 

 would this reflect in your curves? 



JANSKY: Comparing the values of maximal working meta- 

 bolism and those of resting metabolism, we can see, that at the 

 same environmental temperature the animals produce more heat 

 at the level of maximal metabolism than in the resting state with- 

 out a significant change in body temperature. This would suggest 

 a certain decrease in total body insulation. On the other hand 

 the values of maximal working metabolism in all species of ani- 

 mals that we studied form a definite exponent to the body weight. 

 This would mean that there are no changes in total body insula- 

 tion in working animals of different species. 



KLEIBER: This change in insulation makes shivering ineffi- 

 cient because it increases the dissipation of heat. 



HART: I am interested to know whether anyone has an opinion 

 on the method of total cyt-ox activity as a measure of the theoreti- 

 cal maximum metabolic capacity. 



HANNON: Theoretically, at least, this enzyme should be a 

 good index of maximum metabolic capacity since most of the 

 oxidative processes are eventually channeled through it. The 

 manometric method of assaying it, however, is often open to 

 criticism since you are using ascorbic acid to reduce the cyto- 

 chrome c substrate. There is always a possibility that the ascorbic 



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