676 THE RESPIRATION AND [pt. iii 



It is very interesting to note that the respiration shows a distinct 

 increase after fertilisation, the extreme instance being a rise of two 

 and a half times in the case of carbon dioxide and of nearly three 

 times in the case of oxygen. 



Turning now to the respiratory quotients, it is evident that there 

 is not much difference before and after fertiUsation, a fact which is 

 interesting in view of the constancy of the calorific quotient in 

 echinoderm eggs. Bialascewicz & Bledovski admitted the difference 

 between o-6o and 0-72 the theoretical fat respiratory quotient, but 

 claimed quite justifiably that in many other cases where vigorous 

 catabolism of fatty acids is known to be going on, the respiratory 

 quotient is often below 0-7. At the same time, they saw in the lowness 

 of it in this case evidence for a simultaneous activity of hydrolytic 

 processes, both before and after fertilisation, though they did not 

 give any more detailed indication of the part they supposed these to 

 be playing in the metabolism of the embryo, 



Bialascewicz & Bledovski went on to measure various entities in 

 the egg and the early stages of development. Weighing, they found, 

 presented great difficulties, so they measured the diameter micro- 

 scopically, calculated its surface and its volume which, when multi- 

 plied by the specific gravity (1-102), gave the mass. From these 

 investigations the following figures resulted : 



Oxygen taken up by unfertilised eggs 



Per 1 000 eggs Per i sq. Per 1000 gm. 

 (c.mm.) metre surface egg-weight 

 (c.c.) (c.c.) 



Averages of 8 experiments ... ... ... 74-5 7-1 21-6 



Percentage scattering of individual observations 330 19-2 i8-o 



From these measurements it appeared that the smallest deviation 

 from the average value resulted when the oxygen taken up was 

 referred to the actual weight of the eggs, though evidently the 

 surface is nearly as good a measure. This shows that the oxygen 

 uptake depends not so much on the quantity of individuals measured 

 as on their surface, or even more, on their weight. The cubic centi- 

 metres of oxygen absorbed per kilo of unfertilised egg-weight may 

 be compared in an interesting way with the cubic centimetres of 

 oxygen absorbed per kilo of adult frog (Bohr) ; the figures are re- 

 spectively 21-6 and 261-8, so that the metaboHc rate is evidently 

 far higher in the adult frog than in the unfertilised frog's egg. 



