MODERN EVOLUTION. 



167 



consequently multiply, while the others would de- 

 crease; not only from their inability to sustain the 

 attacks of disease, but from their incapacity of con- 

 tending with their more vigorous neighbours." 



When the simplicity of the long-hidden solution 

 is brought home, we can understand Huxley's reflec- 

 tion on mastering the central idea of the Origin: 

 " How extremely stupid not to have thought of 

 that! " Twelve years elapsed before Darwin followed 

 up his world-shaking book with the Descent of Man. 

 But the ground had been prepared for its reception 

 in the decade between i860 and 1870. Quoting 

 Grant Allen's able summary of the advance of the 

 theory of Evolution in his Charles Darwin : " One 

 by one the few scientific men who still held out 

 were overborne by the weight of evidence. Geology 

 kept supplying fresh instances of transitional forms; 

 the progress of research in unexplored countries kept 

 adding to our knowledge of existing intermediate 

 species and varieties. During those ten years, Her- 

 bert Spencer published his First Principles, his 

 Biology, and the remodelled form of his Psychology; 

 Huxley brought out Man's Place in Nature, the 

 Lectures on Comparative Anatomy, and the Intro- 

 duction to the Classification of Animals; Wallace 

 produced his Malay Archipelago and his Contribu- 

 tions to the Theory of Natural Selection (Bates, we 

 may here add to Mr. Allen's list, published his paper 

 on Mimicry in 1861, and his Naturalist on the 

 Amazons in 1863); and Galton wrote his admirable 



