Page - 210 - in The Origin of Species

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