210 ORIGIN OF SPECIES 



the Creator (but this latter point is beyond the scope of 

 scientific discussion), or for the sake of mere variety, a view 

 already discussed. Such doctrines, if true, would be abso- 

 lutely fatal to my theory. I fully admit that many structures 

 are now of no direct use to their possessors, and may never 

 have been of any use to their progenitors; but this does not 

 prove that they were formed solely for beauty or variety. 

 No doubt the definite action of changed conditions, and the 

 various causes of modifications, lately specified, have all 

 produced an effect, probably a great effect, independently of 

 any advantage thus gained. But a still more important con- 

 sideration is that the chief part of the organisation of every 

 living creature is due to inheritance ; and consequently, 

 though each being assuredly is well fitted for its place in 

 nature, many structures have now no very close and direct 

 relation to present habits of life. Thus, we can hardly be- 

 lieve that the webbed feet of the upland goose or of the 

 frigate-bird are of special use to these birds; we cannot be- 

 lieve that the similar bones in the arm of the monkey, in the 

 fore-leg of the horse, in the wing of the bat, and in the 

 flipper of the seal, are of special use to these animals. We 

 may safely attribute these structures to inheritance. But 

 webbed feet no doubt were as useful to the progenitor of 

 the upland goose and of the frigate-bird, as they now are to 

 the most aquatic of living birds. So we may believe that the 

 progenitor of the seal did not possess a flipper, but a foot 

 with five toes fitted for walking or grasping; and we may 

 further venture to believe that the several bones in the limbs 

 of the monkey, horse, and bat, were originally developed, 

 on the principle of utility, probably through the reduction of 

 more .numerous bones in the fin of some ancient fish-like 

 progenitor of the whole class. It is scarcely possible to de^ 

 cide how much allowance ought to be made for such causes 

 of change, as the definite action of external conditions, so- 

 called spontaneous variations, and the complex laws of 

 growth ; but with these important exceptions, we may con- 

 clude that the structure of every living creature either now 

 is, or was formerly, of some direct or indirect use to its 

 possessor. 



With respect to the belief that organic beings have been 



