SECT. 4] HEAT-PRODUCTION OF THE EMBRYO 



671 



important advance, for although it had always been considered that 

 the Warburg-Meyerhof-Shearer experiments on echinoderm eggs 

 had the stamp of universality about them, there was no evidence 

 that the rise in oxygen consumption at fertilisation held for any 

 other phylum. Plotting the oxygen consumed by her minnow eggs 

 per unit weight in each lo-minute period, against the time, she found 

 that it rose to a peak 60 minutes after fertilisation, at which time it 

 was 1 7 times the unfertilised egg value. Then, falling past the time of 

 first cleavage (120 minutes) it reached the unfertilised egg value 

 at 210 minutes. Boyd did not take any readings after the 310th 



E T 



O 



c 0- 



£ 0- 

 o 



•- 0- 



Q.0- 



en 

 d 0- 



> 0- 



150 180 210 

 Time in minLutes 

 Fig. 127. 



240 270 300 330 



minute but a few extra experiments showed her that Scott & Kelli- 

 cott's rise at the gth day (beginning of the circulation) could be 

 confirmed. Her curve for the first few hours after fertilisation is 

 given in Fig. 127. 



4-7. Respiration of Amphibian Embryos 



Bataillon was also the first to make quantitative experiments on 

 the respiratory exchange of developing amphibian eggs. His papers 

 already quoted are interesting, in that they form one of the most 

 detailed attempts at correlation between morphological and bio- 

 chemical data which have ever been made. In this they suffer from two 

 disadvantages, firstly that Bataillon's methods would not be regarded 

 now as accurate although Hyman's work is to some extent con- 

 firmatory, and secondly that he made one or two doubtful theoretical 



