478 THE WONDER OF LIFE 



structure. Thus we may begin to think of the conditions 

 of agency, of experimenting, of trafficking with t^ime, and 

 of multiplying. 



Power of Reproducing. — Growth is self -increase, and 

 it leads on to reproduction which is self-multiphcation. 

 In a simple organism — a nucleated corpuscle of Uving 

 matter — growth proceeds up to a certain point which 

 we call the hmit of growth. Beyond that it is dangerous 

 for the corpuscle to grow, unless indeed it secures at the 

 same time great increase of surface. We have already 

 referred (p. 396) to what was pointed out by Herbert 

 Spencer and others, that if the corpuscle be a sphere, as it 

 often is, the volume (whose contents have to be kept ahve) 

 increases as the cube of the radius, whereas the surface 

 (through which the keeping aUve is effected) increases 

 only as the square. Thus if it grow beyond a certain size, 

 the corpuscle gets into difficulties. There is also an 

 optimum ratio between the nucleus and the rest of the 

 cell-substance. 



Development. — We are trying to see the essential 

 criteria of hfe in a logical order. The power of sustained 

 metabohsm — of balancing accounts — makes activity and 

 growth possible ; growth naturally leads on to multiphca- 

 tion ; and the power of development that an isolated frag- 

 ment, or sample, or, it may be, germ- cell possesses of re- 

 expressing the whole is surely a continuation of the restitu- 

 tion and regrowth which goes on to make good the body's 

 wear and tear, and of the regeneration which is exhibited 

 when a lost part is replaced. Development is the making 

 visible of the latent manifoldness of the hberated fragment, 

 or sample, or cell. It is the expression of latent possi- 

 bihties— it is, subjectively regarded, a kind of self-expres- 



