574 THE WONDER OF LIFE 



active in various ways. But they are by no means indis- 

 pensable. On the whole, in the present state of our know- 

 ledge, it seems that the best working hypothesis is Weis- 

 mann's. He supposes that the germ-plasm includes special 

 ' regeneration-determinants ' which are distributed appro- 

 priately through the body and he quietly hke garrisons in 

 strategic places, awaiting a possible awakening stimulus. 

 Perhaps, however, it is at present wiser to leave our 

 conception of the arrangements for regeneration somewhat 

 vague, and to concentrate attention on the case for Les- 

 sona's law — that regenerative capacity tends to occur in 

 those animals and in those parts of animals which are in 

 the natural conditions of their hfe particularly hable to 

 injury, always provided that the part lost be of real import- 

 ance, and that the injury be not fatal. All of which comes 

 to this, that the distribution of the regenerative capacity 

 is adaptive, and can be accounted for on the theory of 

 Natural Selection. 



The Crowning Wonder of Evolution. 



We have become so familiar with the general idea of 

 organic evolution that we have ceased to wonder enough. 

 It should be a thought to thrill us, that we and the multi- 

 tudinous, varied, intricate, and always beautiful world of 

 hfe around us have grown by infinitely slow gradations 

 from an apparently simple beginning. Through unreckon- 

 able ages Life has been slowly creeping upwards, possessing 

 and conquering the earth ever more thoroughly, unfolding 

 new and imsuspected potentiahties seon after seon, and 

 afiordingusin fact no small part of the material that has 

 gone to build up our conception of Progress. 



