WHAT IS DARWINISM? 99 



rayed are attractive, and thus become the 

 progenitors of their race. Against this expla- 

 nation the Duke earnestly protests. He re- 

 fers to the gorgeous adorned class of Humming- 

 birds, of which naturalists enumerate no less 

 than four hundred and thirty different species, 

 distinguished one from the other, in general, 

 only by their plumage. " Now," he asks, 

 " what explanation does the law of natural se- 

 lection give, — I will not say of the origin, but 

 even of the continuance of such specific vari- 

 eties as these ? None whatever. A crest of 

 topaz is no better in the struggle of existence 

 than a crest of sapphire. A frill ending in 

 spangles of the emerald is no better in the 

 battle of life than a frill ending in spangles 

 of the ruby. A tail is not affected for the pur- 

 poses of flight, whether its marginal, or its 

 central feathers are decorated with white. It 

 is impossible to bring such varieties into any 

 physical law known to us. It has relation 

 however to a Purpose, which stands in close 

 analogy with our knowledge of purpose in 

 the works of men. Mere beauty and mere 

 variety, for their own sake, are objects which 

 we ourselves seek, when we can make the 

 forces of nature subordinate to the attain- 



