THE THEORY OF COURTSHIP 151 



natural selection did not suffice by itself to explain all 

 the details of structure in man, had invented sexual 

 selection as a supplementary principle to help it over 

 the hard places. Those who wrote and spoke in this 

 thoughtless fashion could have had but a very inadequate 

 idea of Darwin's close experimental methods of enquiry. 

 As a matter of fact, indeed, they were entirely wrong; 

 the doctrine of sexual selection itself, already faintly 

 foreshadowed by Erasmus Darwin in the 'Zoonomia,' 

 had been distinctly developed in the first edition of the 

 ' Origin of Species ' with at least as much provisional 

 elaboration as any other equally important factor in the 

 biological drama as set forth in that confessedly intro- 

 ductory work. Nay, Haeckel had caught gladly at the 

 luminous conception there expressed, even before the 

 appearance of the ' Descent of Man,' and had worked it 

 out in his ' Generelle Morphologic,' with great insight, to 

 its legitimate conclusions in many directions. Indeed, 

 the sole reason why so much space was devoted to the 

 subject in Darwin's work on human development was 

 simply because there for the first time an opportunity 

 arose of utilising his vast store of collected information on 

 this single aspect of the evolutionary process. It was no 

 afterthought, but a necessary and inevitable component 

 element of the fully-developed evolutionary concept. 



Still, it cannot be denied that naturalists generally 

 did not accept with effusion the new clause in the 

 evolutionary creed. Many of them hesitated; a few 

 acquiesced ; the majority more or less openly dissented. 

 But Darwin's belief remained firm as a rock. ' I am 

 glad you defend sexual selection,' he wrote a few years 

 later in a private letter ; ' I have no fear about its ulti- 



