Whatever may be said of the credit due to other scientists for investigation or discovery in natural selection, the preeminence of Darwin in this field is undisputed.  If of any scientific book it can be said that its appearance was “epoch-making” it is true of Darwin’s work On the Origin of Species by Means of Natural Selection, or the Preservation of Favored Races in the Struggle for Life.  Not only did it command the earnest attention of the scientific and literary world, but it awakened the interest of thoughtful persons everywhere.  Later research and criticism have modified the effect of his conclusions and led to new results, but the “Darwinian theory” or “Darwinism” still holds and seems likely long to maintain a central place in the history of modern scientific development.

Charles Robert Darwin was born at Shrewsbury, England, February 12, 1809.  He was the grandson of Erasmus Darwin, an eminent physician, naturalist, and poet, who in 1794-1796 published an important work entitled Zooenomia, or the Laws of Organic Life.  Charles Darwin was heir to a fortune, and in youth the possession of ample means prevented him from taking any deep interest in studying for a profession, although he did study medicine and, later, for the church.  But before reaching his majority he turned to natural history.  At Cambridge he enjoyed an intimacy with the distinguished botanist Professor John S. Henslow, who quickened the young man’s enthusiasm for scientific investigation.

In his twenty-third year Darwin went as naturalist with a government expedition to Patagonia.  The voyage, in the Beagle (1831-1836), was continued round the world.  Darwin’s journals of the expedition served him in his later work, and also furnished much material for popular information.  From 1842, when he went to reside at Down, in Kent, he devoted himself wholly to a life of scientific research and writing.

Since it is not an uncommon error to confound natural selection with evolution, it may be well to point out that, while based on evolution, Darwinism is distinct from it.  Evolution is the development of new organisms through heredity, variation, and adaptation.  Darwinism, or the doctrine of natural selection, as best defined in these pages by Darwin himself, is seen to involve quite different factors from those of evolution as thus restricted.  For candor and childlike simplicity, the writings of Darwin are especially noteworthy among the modest utterances of great men, and nowhere are these qualities more strikingly revealed than in the following account of the production of his principal work.

From September, 1854, I devoted my whole time to arranging my huge pile of notes, to observing, and to experimenting in relation to the transmutation of species.  During the voyage of the Beagle I had been deeply impressed by discovering in the pampean formation great fossil animals covered with armor like that on the existing armadillos; secondly, by the manner in which closely allied animals replace one another in proceeding southward over the continent; and thirdly, by the South American character of most of the productions of the Galapagos Archipelago, and more especially by the manner in which they differ slightly on each island of the group, none of the islands appearing to be very ancient, in a geological sense.