I.—­The Discovery of Natural Selection

“There are not many joys in human life equal to the joy of the sudden birth of a generalisation, illuminating the mind after a long period of patient research.  What has seemed for years so chaotic, so contradictory, and so problematic takes at once its proper position within an harmonious whole.  Out of the wild confusion of facts and from behind the fog of guesses—­contradicted almost as soon as they are born—­a stately picture makes its appearance, like an Alpine chain suddenly emerging in all its grandeur from the mists which concealed it the moment before, glittering under the rays of the sun in all its simplicity and variety, in all its mightiness and beauty.  And when the generalisation is put to a test, by applying it to hundreds of separate facts which seemed to be hopelessly contradictory the moment before, each of them assumes its due position, increasing the impressiveness of the picture, accentuating some characteristic outline, or adding an unsuspected detail full of meaning.  The generalisation gains in strength and extent; its foundations grow in width and solidity; while in the distance, through the far-off mist on the horizon, the eye detects the outlines of new and still wider generalisations.  He who has once in his life experienced this joy of scientific creation will never forget it; he will be longing to renew it; and he cannot but feel with pain that this sort of happiness is the lot of so few of us, while so many could also live through it—­on a small or on a grand scale—­if scientific methods and leisure were not limited to a handful of men.”—­PRINCE KROPOTKIN, “Memoirs of a Revolutionist.”

The social and scientific atmosphere in which Wallace found himself on his return from his eight years’ exile in the Malay Archipelago was considerably more genial than that which he had enjoyed during his previous stay in London following his exploration of the Amazon.  His position as one of the leading scientists of the day was already recognised, dating from the memorable 1st of July, 1858, when the two Papers, his own and Darwin’s, on the theory of Natural Selection had been read before the Linnean Society.

During the four years which had elapsed since that date the storm of criticism had waxed and waned; subsiding for a time only to burst out afresh from some new quarter where the theory bade fair to jeopardise some ancient belief in which scientist or theologian had rested with comparative satisfaction until so rudely disturbed.

During this period Wallace had been quietly pursuing his researches in the Malay Archipelago, though not without a keen interest in all that was taking place at home in so far as this reached him by means of correspondence and newspaper reports—­his only means of keeping in touch with the world beyond the boundaries of the semi-civilised countries in which he was then living.

In order to follow the story of how the conception of the theory of Natural Selection grew and eventually took definite form in Wallace’s mind, independently of the same development in the mind of Darwin, we must go back to a much earlier period in his life, and as nearly as possible link up, the scattered remarks which here and there act as signposts pointing towards the supreme solution which has made his name famous for all time.