JoLY — The Abundance of Life. 59 



Was this the onlj possible dynamic order ruling in material 

 systems it is quite certain the myriads of ants and pines never 

 could have been, except all generated by creative act at vast 

 primary expenditure of energy. Grrowth and reproduction would 

 have been impossible in systems which retarded change at every 

 step and never proceeded in any direction but in that of dissipation. 

 Once created, indeed, it is conceivable that, as heat engines, they 

 might have dragged out an existence of alternate life and death. 

 Life in the hours of sunshine, death in hours of darkness. No 

 final death, however, their lot, till their parts were simply worn 

 out by long use, never made good by repair. But the sustained 

 and increasing activity of organized nature is a fact ; therefore 

 some other order of events must be possible. 



General Dynamic Conditions attending Animate Actions. 



What is the actual dynamic attitude of the organic heat engine, 

 the vegetable organism ? I speak, here, in the first place, not of 

 intervening, but of resulting phenomena. 



The 3'oung leaf exposed to solar radiation is small at first, and 

 the quantity of radiant energy it receives in unit of time cannot 

 exceed that which falls upon its surface. But what is the effect of 

 this energy ? Not to produce a retardative response, but an accele- 

 rative : for, in the enlarging of the leaf by growth, the plant 

 opens for itself new channels of supply. 



If we refer to "the living protoplasm which, with its un- 

 known molecular arrangement, is the only absolute test of the 

 cell and of the organism in general,"^ we find a similar attitude 

 towards external sources of available energy. In the act of growth 

 increased rate of assimilation is involved, so that there is an accele- 

 ration of change till a bulk of maximum activity is attained. The 

 surface, finally, becomes too small for the absorption of energy 

 adequate to sustain further increase of mass (Spencer^), and the 

 acceleration ceases. The waste going ou in the central parts is 

 then just balanced by the renewal at the surface. By division, 

 by spreading of the mass, by outflowing processes, the normal 

 activity of growth may be restored. Till this moment nothing 



1 Glaus, "Zoology," p. 13. 



2 Geddes and Thomson, «' The Evolution of Sex," p. 220. 



