FACTORS OF ORGANIC EVOLUTION 39 



interrogation of Nature which Bacon advocated. 

 By such means alone can the analogical method 

 yield any valuable conclusions whatsoever. But 

 whereas the poets' and metaphysicians' employment 

 of analogy entails little mental effort, and occupies 

 only a few seconds, the method that leads to Truth 

 demands infinite patience, perseverance, and fidelity, 

 superadded to rare powers of observation. There is 

 no royal road to knowledge. 



CHAPTER VI 



THE FACTORS OF ORGANIC EVOLUTION- 

 SEXUAL SELECTION 



The "Origin of Species" was the fruit of some twenty 

 years of observation and thought. Thereafter, whilst 

 others bore the brunt of controversy, Darwin re- 

 sumed his work in happy and untroubled personal 

 obscurity. Twelve years later he published his 

 '• Descent of Man," in which is stated another factor 

 in organic evolution which he named " sexual 

 selection." Whilst the action of this factor is by 

 no means confined to man, Darwin considered that 

 it had been of especial importance in his evolution. 

 Concerning this factor there has been, and still 

 is, much biological controversy. In his article 

 " Evolution " l in the tenth edition of the Encyclo- 

 pcedia Britannica, Dr. Chalmers Mitchell expresses 

 the opinion that sexual selection is of considerably 



1 This article is, of course, quite incorrectly named. It deals 

 merely with organic evolution. 



