22 INTRODUCTORY 



Fishes and whales need fins for swimming : they 

 develop them, but from different portions of their 

 bodies. So also with the wings of insects, birds 

 and bats : they are, in each case, grown by a 

 different process. Life, when adopting the water, 

 or the air, as its environment, appears to be 

 wholly indifferent as to the method of adaptation. 

 It concerns itself with results, not with pro- 

 cesses in fact, la fonction fait Vorgane. 



The evolution ot the myriad forms of animal and 

 plant life does not appear to have resulted from 

 the modification of living tissue under the pressure 

 of surrounding forces, but from the action of two 

 vital energies multiplication and variation 

 which have been incessantly forcing living organ- 

 isms into, as it were, a complicated and many- 

 branched system of channels, or moulds (such as 

 we may liken to the arteries of the human body), 

 which represent the almost infinitely varied means 

 of procuring subsistence. The multiplication of 

 individuals supplies the pressure : their variation 

 is the means by which they are able gradually to 

 penetrate each channel of the system. There is 

 enormous wastage : millions of organisms come 

 into the world merely to increase the head of the 

 pressure : millions of variations are useless, do not 

 assist their possessors to find their way into a new 

 channel, and are extinguished as soon as they 

 arise. 



In the history of evolution there are two 

 features which appear to confirm this hypothesis. 

 Firstly, there is the gradual progress of life from 

 the sea to the land, and from the land to the air. 

 Of this, geology assures us. It can hardly be ex- 

 plained by any materialistic theory of adaptation, 

 since the progress must have come about, not by 

 adaptation to environment, but by the extension of 

 life to a new environment. Secondly, there is the 



