SECT. 4] HEAT-PRODUCTION OF THE EMBRYO 705 



put out, on the assumption that the combustion is going on at the 

 expense of fat. The observed and calculated points lie for the most 

 part on exactly the same line. Table 83, which gives the average 

 values for observed and calculated calories evolved per hour on each 

 day, shows up the divergences better. After the early period of heat 

 absorption, there follows a second period in which the observed 

 values are somewhat lower than the calculated ones but by the 

 nth day equivalence has been gained, and, in the third period, 



100 



90 - 

 80 

 70 - 

 60 

 50 

 40 

 30 

 20 

 10 

 

 10 

 20 



Bohr 8^ Hasselbalch 

 (heat production) 



O Observed 

 © Calculated 



J L 



J \ L 



J 1 L 



J \ L 



J I 



10 11 12 13 14 15 16 17 1819 

 Days 



Fig. 145. 



when the heat radiated is reaching high figures, the advantage is 

 rather on the side of the observed values. Bohr & Hasselbalch 

 noticed this fact, and, by a comparison of the percentage differences 

 in each case, showed that they cancelled out almost exactly over the 

 whole time of incubation, the earlier lag on the observed side making 

 up for the later lag on the calculated side. Thus for the entire incuba- 

 tion period 12-16 kilo cal. were experimentally found in the calori- 

 meter, while 1 2- 1 1 kilo cal. were calculated as the expected amount 

 — an excellent agreement. The extreme importance of these experi- 



