ralist, 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.

It was evident that such facts as these, as well as many