502 THE ORIGIN OF SPECIES 



habits or conditions of life; and we can understand on 

 this view the meaning of rudimentary organs. But disuse 

 and selection will generally act on each creature, when it 

 has come to maturity and has to play its full part in the 

 struggle for existence, and will thus have little power on 

 an organ during early life; hence the organ will not be 

 reduced or rendered rudimentary at this early age. The 

 calf, for instance, has inherited teeth, which never cut 

 through the gums of the upper jaw, from an early pro- 

 genitor having well-developed teeth; and we may believe 

 that the teeth in the mature animal were formerly re- 

 duced 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 inheri- 

 tance 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 inexplicable 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 frequently 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 Hblind to understand her meaning. 



Conclusion 



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 



