no RESPIRATORY EXCHANGE OF ANIMALS AND MAN 



TABLE XXI. 



The averages are for the adult animal 462 15 c.c. per kg. and hour, 

 and for the embryo 509 68 ,, ,, 



Within the limits of error the respiratory exchange is therefore the 

 same, and these experiments are especially valuable because standard 

 conditions were secured by the urethane. The respiratory quotient of 

 the embryos was in all cases very nearly i, and it was concluded 

 therefore that the metabolism of the mammal embryo is chiefly a 

 catabolism of carbohydrate. 



In experiments on the eggs of a snake (Coluber natrix] Bohr 

 [1903] found that the respiratory exchange calculated per kilogram 

 of embryo decreased during the period of incubation (Table XXII). 



TABLE XXII. 



The comparison between the embryos and the young snake is not 

 of much value as standard conditions were not observed, while on the 

 other hand the animal had been without food for a very long time. 



By comparing experiments made at 15 with others made at 

 27 to 28 Bohr found that at the higher temperature the development is 

 about thrice as rapid and the production of carbon dioxide about 

 thrice as large. The figures are very uncertain, however, and the con- 

 clusion drawn from the experiments, that the greater part of the energy 

 expended is utilized for the growth of the tissues, is certainly un- 

 warranted as the standard metabolism is greatly increased by the in- 

 crease in temperature. 



