CONCLUSION. 465 



the gums of the upper jaw, from an early progenitor having 



well-developed teeth ; and we may believe, that the teeth in 

 the mature animal were formerly reduced by disuse, owing 

 to the tongue and palate, or lips, having become excellently 

 fitted through natural selection to browse without their 

 aid ; whereas in the calf, the teeth have been left unaffected, 

 and on the principle of inheritance at corresponding ages 

 have been inherited from a remote period to the present 

 day. On the view of each organism with all its separate 

 parts having been specially created, how utterly inexplica- 

 ble is it that organs bearing the plain stamp of inutility, 

 such as the teeth in the embryonic calf, or the shrivelled 

 wings under the soldered wing-covers of many beetles, 

 should so frequentty occur. Nature may be said to have 

 taken pains to reveal her scheme of modification, by means 

 of rudimentary organs, of embryological and homologous 

 structures, but we are too blind to understand her meaning, 



I have now recapitulated the facts and considerations 

 which have thoroughly convinced me that species have been 

 modified, during a long course of descent. This has been 

 effected chiefly through the natural selection of numerous 

 successive, slight, favorable variations; aided in an impor- 

 tant manner by the inherited effects of the use and disuse 

 of parts ; and in an unimportant manner, that is, in relation 

 to adaptive structures, whether past or present, by the 

 direct action of external conditions, and by variations 

 which seem to us in our ignorance to arise spontaneously. 

 It appears that I formerly underrated the frequency and 

 value of these latter forms of variation, as leading to per- 

 manent modifications of structure independently of natural 

 selection. But as my conclusions have lately been much 

 misrepresented, and it has been stated that I attribute the 

 modification of species exclusively to natural selection, I 

 may be permitted to remark that in the first edition of this 

 work, and subsequently, I placed in a most conspicuous 

 position — namely, at the close of the Introduction — the 

 following words : " I am convinced that natural selection 

 has been the main but not the exclusive means of modi- 

 fication." This has been of no avail. Great is the power 

 of steady misrepresentation ; but the history of science shows 

 that fortunately this power does uot long endure. 



It can hardly be supposed that a false theory would 

 explain, in so satisfactory a manner as does the theory 

 of natural selection, the several larse classes of facts above 



