RECAPITULATION AND CONCLUSION 423 



canon of "Natura non facit saltum," which every fresh addition 

 to our knowledge tends to confirm, is on this theory intelligible. 

 We can see why throughout nature the same general end is gained 

 by an almost infinite diversity of means, for every peculiarity 

 when once acquired is long inherited, and structures already modi- 

 fied in many different ways have to be adapted for the same 

 general purpose. We can, in short, see why nature is prodigal in 

 variety, though niggard in innovation. But why this should be a 

 law of nature if each species has been independently created, no 

 man can explain. 



Many other facts are, as it seems to me, explicable on this theory. 

 How strange it is that a bird, under the form of a woodpecker, 

 should prey on insects on the ground; that upland geese, which 

 rarely or never swim, should possess webbed feet; that a thrush- 

 like bird should dive and feed on sub-aquatic insects; and that 

 a petrel should have the habits and structure fitting it for the life 

 of an auk I and so in endless other cases. But on the view of each 

 species constantly trying to increase in number, with natural se- 

 lection always ready to adapt the slowly varying descendants of 

 each to any unoccupied or ill-occupied place in nature, these facts 

 cease to be strange, or might even have been anticipated. 



We can to a certain extent understand how it is that there is 

 so much beauty throughout nature; for this may be largely at- 

 tributed to the agency of selection. That beauty, according to our 

 sense of it, is not universal, must be admitted by every one who 

 will look at some venomous snakes, at some fishes, and at certain 

 hideous bats with a distorted resemblance to the human face. 

 Sexual selection has given the most brilliant colors, elegant pat- 

 terns, and other ornaments to the males, and sometimes to both 

 sexes, of many birds, butterflies, and other animals. With birds 

 it has often rendered the voice of the male musical to the female, 

 as well as to our ears. Flowers and fruit have been rendered con- 

 spicuous by brilliant colors in contrast with the green foliage, in 

 order that the flowers may be easily seen, visited and fertilized 

 by insects, and the seeds disseminated by birds. How it comesN 

 that certain colors, sounds, and forms should give pleasure to man \ 

 and the lower animals, that is, how the sense of beauty in its \ 

 simplest form was first acquired, we do not know any more, than 

 how certain odors and flavors were first rendered agreeable. / 



As natural selection acts by competition, it adapts and improves 

 the inhabitants of each country only in relation to their co- 

 inhabitants ; so that we need feel no surprise at the species of any 

 one country, although on the ordinary view supposed to have been 



