THE CAUSE OF SPONTANEOUS VARIATIONS 105 



Selection has been regarded as under a cloud. We are told 

 that it is inadequate to explain all the facts of evolution. 

 The theory of recapitulation, also, has been under a cloud. 

 We are told that it is opposed to the facts. But if the child 

 recapitulates the development of his parent there can be no 

 more doubt of the recapitulation of the life-history than there 

 can be of the truth of a proposition which has been demon- 

 strated mathematically. The inability of embryologists to 

 trace the life-history in the development merely demonstrates 

 the fact that there have been variations in the past, and that 

 these have been recapitulated. The neglect of the doctrine of 

 recapitulation by students of heredity has led directly to the 

 prevailing disbelief in the adequacy of Natural Selection and 

 to the formulation of a number of impossible morphological 

 hypotheses. But the one truth is the complement of the 

 other. If Nature be scrutinized by the aid of both we gain a 

 wonderful clearness of vision. It is as if, standing on a hill 

 and peering into a mist-hidden valley, we put on magic 

 glasses. The mists vanish. Things erstwhile dim and 

 mysterious become in a moment plain and consistent. The 

 great scheme of Nature spreads like a map at our feet. 



