272 SYMBWGENESIS 



Spencer also thinks that a definite cause must be assign- 

 able for apparently spontaneous variations. 



In any series of dependent changes a small initial difference often 

 works a marked difference in the results. The mode in which a particular 

 breaker bursts on the beach may determine whether the seed of some 

 foreign plant which it bears is or is not stranded may cause the presence 

 or absence of this plant from the flora of the land ; and may so affect for 

 millions of years, in countless ways, the living creatures throughout the 

 land. 



Whilst this is quite true, yet it remained to discover the 

 definite and persistent principle, capable, as Samuel Butler 

 would say, of acting as a rudder and compass to the accumula- 

 tion of variations, and of making it keep steadily on one course 

 for every species, until eventually many havens far remote 

 from one another are safely reached. 



The reproductive centres must begin to differentiate from 

 the very outset, says Spencer, " since the process of nutrition 

 cannot be absolutely alike for all." (Italics mine.) 



What has escaped him here is that if the unlikenesses and 

 fluctuations following in the wake of metabolic fluctuations 

 have not generally assumed undue proportions, this is entirely 

 due to those beneficent dual amphimixis and concomitant safe- 

 guarding effects resulting from proper feeding on which 

 I have all along insisted. There are also, according to 

 Spencer, qualitative differences different kinds of influences 

 affecting the germ-cells or sperm-cells. "Amid countless 

 different combinations of units derived from parents, and 

 through them from ancestors, immediate and remote amid 

 the various conflicts in their slightly different polarities, 

 opposing and conspiring with each other in all ways and 

 degrees ; there will from time to time arise special proportions 

 causing special deviations." And he cites a very valid objection 

 to his own " chance " view. It is this : "As the members of a 

 species whose circumstances have been altered will be affected 

 in the same manner, the results, when they begin to show 

 themselves in descendants, will show themselves in the same 



