698 



THE RESPIRATION AND 



[PT. m 



period, 3-0225 litres or 5-939 gm. of carbon dioxide were produced, 

 so that, calculating from an average respiratory quotient of 0-677, 

 4-465 litres or 6-384 gm. of oxygen was used, and that value was, 

 indeed, very close to the one experimentally found. Hasselbalch 

 reckoned that, as the 5-939 gm. of carbon dioxide given off corre- 

 sponded to 1-620 gm. of carbon, and as, according to Liebermann, 

 egg-fat contained 71-67 per cent, carbon, 1-620 gm. of carbon ac- 

 counted for 2-260 gm. of fatty acids. This was in very encouraging 

 agreement with Lieber- 

 mann's figure, calculated 

 from chemical analysis, that 

 2-762 gm. of fatty acids dis- 

 appeared during develop- 

 ment. It was not unnatural 

 that Hasselbalch should 

 conclude that fatty acids 

 were the sole source of em- 

 bryonic energy during in- 

 cubation, though to do so 

 was certainly to forget the 

 presence of protein break- 

 down-products in the allan- 

 toic fluid, so obvious in the 

 egg, and to take insufficient 

 account of the intervention 

 of more complicated pro- 

 cesses than the simple oxida- 

 tion of fatty acids to carbon dioxide and water. From his oxygen 

 figures, Hasselbalch went on to calculate the metabolic rate, which 

 worked out in good confirmation of the rates reported in the previous 

 paper, and is shown in Fig. 143. The weight of the membranes is not 

 included in this calculation, and until some information concerning 

 their respiratory intensity is available, their influence on the metabolic 

 rate curve cannot be assessed (cf the data of Bycrly in Appendix i). 

 Hasselbalch concluded as the result of his experiments that an 

 exceedingly small amount of a gas other than carbon dioxide was 

 lost by the egg during its development, and believed it to be nitrogen. 

 He returned to this puzzling phenomenon in a subsequent paper in 

 which he again asserted its objectiveness, maintaining that 0-5 c.c^ 



3 4 5 6 7 8 



121314 1516 17 1819' 



Fig. 143. 



i 



