336 'DESCENT OF MAN —EXPRESSION. [1872. 



esting connecting varieties or links were here absent. I re- 

 joice to think that I formerly said as emphatically as I could, 

 that neither isolation nor time by themselves do anything for 

 the modification of species. Hardly anything in your essay 

 has pleased me so much personally, as to find that you believe 

 to a certain extent in sexual selection. As far as I can judge, 

 very few naturalists believe in this. I may have erred on 

 many points, and extended the doctrine too far, but I feel 

 a strong conviction that sexual selection will hereafter be 

 admitted to be a powerful agency. I cannot agree with what 

 you say about the taste for beauty in animals not easily vary- 

 ing. It may be suspected that even the habit of viewing 

 differently coloured surrounding objects would influence their 

 taste, and Fritz Miiller even goes so far as to believe that the 

 sight of gaudy butterflies might influence the taste of distinct 

 species. There are many remarks and statements in your 

 essay which have interested me greatly, and I thank you for 

 the pleasure which I have received from reading it. 

 With sincere respect, I remain. 



My dear Sir, yours very faithfully, 



Charles Darwin. 



P.S. — If you should ever be induced to consider the whole 

 doctrine of sexual selection, I think that you will be led to 

 the conclusion, that characters thus gained by one sex are 

 very commonly transferred in a greater or less degree to the 

 other sex. 



[With regard to Moritz Wagner's first Essay, my father 

 wrote to that naturalist, apparently in 1868 :] 



Dear and respected Sir, — I thank you sincerely for 

 sending me your ' Migrationsgesetz, &c.,' and for the very 

 kind and most honourable notice which you have taken of my 

 works. That a naturalist who has travelled into so many and 

 such distant regions, and who has studied animals of so many 

 classes, should, to a considerable extent, agree with me, is, I 



