Processes of the Echinoderm Egg during Fertilisation. 425 



11. On fertilisation a greatly increased liberation of chemical energy is 

 brought about within the ovum. This is shown by the increased oxygen 

 consumption of the fertilised egg-cell combined with its greatly increased 

 carbon dioxide and heat liberation. 



12. As, however, the calorific quotient of the unfertilised and the fertilised 

 egg-cell is approximately the same in both instances, little or almost a 

 negligible quantity of this energy is expended in bringing about the visible 

 morphological structure of the developing ovum. It is probably employed 

 in keeping the living substance itself intact as a physical system. 



REFERENCES. 



(1) Meyerhof, 0., " Untersuchungen iiber Warmetonung der Vitalen Oxydationsvorgange 



in Eiern, : ' I, II, III, 'Biochem. Zeit.,' vol. 35. p. 246 (1911). 



(2) Warburg, O., " Beobachtungen iiber die Oxydationsprozesse im Seeigelei," ' Zeit. f. 



Physiol. Chem., ! vol. 57, p. 1 (1908). 



(3) Shearer, C, " On the Amount of Heat liberated by Bacillus coll when Grown in the 



Presence of Free Amino- Acids," 'Jr. Physiol.,' vol. 55, p. 50 (1921). 



(4) Shearer, De Morgan and Fuchs. " On the Experimental Hybridization of Echinoids," 



' Phil. Trans., 5 B, vol. 204, p. 255 (1914). 



(5) Barcroft, J., 'The Respiratory Function of the Blood,' Cambridge, 1914. 



(6) Shearer, C, "On the Oxidation Processes of the Echinoderm Egg during Fertilisa- 



tion," ' Roy. Soc. Proc.,' B, vol. 93, p. 213 (1922). 



(7) Hill, A. V., " A New Form of Differential Micro-Calorimeter for the Estimation of ' 



Heat Production in Physiological, Bacteriological, or Ferment Actions," 'Jr. 

 Physiol.,' vol. 43, p. 261 (1911). 



