SECT. 3] AND ORGANISATION 613 



a fine membrane, below it fluid of high viscosity, next fluid of rela- 

 tively low viscosity, and within this the nucleus, which in the resting 

 stage is simply a bag of fluid enclosed in a delicate membrane. How 

 shall sources and sinks of energy be maintained in a fluid composed 

 of 80 per cent, of water? They are undoubtedly there, for the egg 

 is a going concern, taking in oxygen and maintaining itself by ex- 

 penditure of energy. . . . The egg's simplicity is not that of a machine 

 or a crystal, but that of a nebula. Gathered into it are units relatively 

 simple but capable by their combinations of forming a vast number 

 of dynamical systems into which they will fall as the distribution of 

 energy varies.'* 



END OF VOLUME I 



CAMBRIDGE: PRINTED BY W. LEWIS, M.A., AT THE UNIVERSITY PRESS 



