86 THE COMING OF MAN 



growing mass as a whole, and the physiological autonomy of 

 the cells falls into the background." 



If we were not altogether wrong in the conclusion of our 

 last chapter that the whole process of evolution bears all 

 the marks of a certain natural logic, if there is clearly direction 

 in the current of life, there must be here also some guiding, 

 controlling energy above or behind the competing individuals 

 and groups. A river forces its way through barriers and 

 seems to make its own channel. Yet the lines of the river 

 system are determined in the end by the natural physical and 

 geological features of its drainage-basin. How far is the 

 course of the current of evolution determined or modified by 

 surrounding conditions, by Nature, how far by inherent ten- 

 dencies? 



The courses of the different balls in a charge of grape- 

 shot fired from a cannon are evidently due to two sets of 

 forces — 1. their initial velocity and the direction of aim, 

 2. the deflecting power of resisting objects or forces — or the 

 different balls might roll rapidly down a steep mountain side. 

 In the first case velocity and direction of course would be 

 determined largely by initial impulse; in the last by the at- 

 traction of the earth and by the inequalities of its surface. 

 If we lay great weight on initial tendencies, inherent in the 

 germ, we shall lay less stress on the guidance and control of 

 Natural Selection; if the directive tendency of the germ is small 

 or weak, the burden and '^ responsibility " of natural selec- 

 tion must increase in similar proportion. 



Years ago the botanist Nageli propounded an ingenious and 

 elaborate theory of evolution, as dependent almost entirely on 

 inherent initial tendency. Natural selection played a very 

 subordinate part. His theory seems one-sided. 



Let us glance at the view of an extreme, perhaps somewhat 

 old-fashioned neo-Darwinian. The seat and center of the 

 controlling energy lies in the continuous chain of germ-cells 

 stretching from protozoan to man ; always buried and shielded 

 deep in the body of the parent beyond the reach of external 

 agencies or the habits and acts of their bearers, except in so 



