Processes of the Echinoderm Egg during Fertilisation. 411 



so low, however, as to suggest that his data for the heat liberation or the 

 oxygen consumption are incorrect, or that the oxidation processes of the egg- 

 cell on fertilisation are of a different character from those of adult 

 metabolism. It has been shown by Zunst and Schumberg, Eauber, Pfluger 

 and others, that when fat is consumed this figure should be in the vicinity 

 of 3"3, when protein 3 - 2, and carbohydrate 2 9. Meyerhof could find no carbo- 

 hydrate in the egg, and there could be no destruction of protein, but sufficient 

 fat was found in tbe egg to give the quotient observed. In the case of fresh 

 sperm. Q was 3"1 or nearly normal. The carbon dioxide production by the 

 eggs was not measured. 



The most important fact, however, arising from Meyerhof's experiments 

 was that, whether he took the unfertilised egg, the fertilised, or the fertilised 

 egg treated with phenylurethane, so that cell formation was inhibited 

 although development proceeded, he found the value of this calorific quotient 

 was always the same. If any of the chemical energy liberated in the egg 

 as the result of the increased oxygen consumption of the egg on fertilization 

 were utilised in producing the visible morphological structure of the egg, 

 then the value of this quotient could not be the same in all these instances. 

 Warburg (2) had already pointed out, that the oxygen consumption of the 

 egg-cell on development always fails to keep pace with the increase in 

 morphological structure. In Arbacia he found the fertilised egg in the 

 one cell stage during the first hour of development consumed 4 c.c. of 

 oxygen ; in the sixth hour, the same quantity of eggs consumed only 

 6'8 c.c, although now the eggs were each composed of thirty-two cells 

 instead of one. 



In another experiment where a larger number of eggs were employed, 

 13 - 2 mgrm. of oxygen was consumed by the eggs in the eight-cell stage, 

 while in the thirty-two cell stage only 20'5 mgrm. was absorbed. Thus, 

 while the oxygen consumption doubled in amount the cellular structure had 

 increased four-fold. 



Meyerhof found the heat production of a quantity of unfertilised eggs 

 containing 140 mgrm. of nitrogen (about 17 million eggs) to be about 

 0"9 grm. calories per hour, while the same quantity of fertilised eggs, 

 liberated 4 — 4'2 grm. calories in this time. In the second hour, the two-cell 

 stage, the heat production rose to 4'5-5 grm.-calories. In the fourth hour, 

 corresponding to the 8-cell stage, it was 6-6 - 5 grm.-calories. In the sixth 

 hour, the thirty-two-cell stage, it was 9'8 grm.-calories, and from this time 

 onwards the heat liberation increased rapidly, until in the eighteenth hour, 

 when the free swimming stage was reached, it was 17'8 grm.-calories per hour, 

 or four times what it was in the first hour of development. Once develop- 



