384 MY LIFE [Chap. 



action of natural selection was diverted from his body to his 

 mind, and thenceforth his physical form remained stable 

 while his mental faculties improved. This paper was greatly 

 admired by Mr. Darwin and several other men of science, 

 who declared it to be entirely new to them ; but owing to its 

 having been published in one of my less known works, 

 "Contributions to the Theory of Natural Selection," it 

 seems to be comparatively little known. Consequently, it 

 still continues to be asserted or suggested that because we 

 have been developed physically from some lower form, so in 

 the future we shall be further developed into a being as 

 different from our present form as we are different from the 

 orang or the gorilla. My paper shows why this will not be ; 

 why the form and structure of our body is permanent, and 

 that it is really the highest type now possible on the earth. 

 The fact that we have not improved physically over the 

 ancient Greeks, and that most savage races — even some of 

 the lowest in material civilization — possess the human form in 

 its fullest symmetry and perfection, affords evidence that my 

 theory is the true one. 



3. In 1867 I gave a provisional solution of the cause of 

 the gay, and even gaudy colours of many caterpillars, which 

 was asked for by Darwin, and which experiment soon proved 

 to be correct. This is referred to in Chapter XXI. of the 

 present volume, and is fully described in my " Natural 

 Selection and Tropical Nature," pp. 82-86. The principle 

 established in this case has been since found to be widely 

 applicable throughout the animal kingdom. 



4. In 1868 I wrote a paper on "A Theory of Birds' 

 Nests," the chief purport of which was to point out and 

 establish a connection between the colours of female birds 

 and the mode of nidification which had not been before 

 noticed. This led to the formulation of the following law, 

 which has been very widely accepted by ornithologists : 

 When both sexes of birds are conspicuously coloured, the nest 



conceals the sitting bird ; but when the male is conspicuously 



