With characteristic caution, however, he kept his essay in his desk, and with equally characteristic ardour, industry and patience went on with the laborious task of accumulating evidence. His friends were of course well aware of the nature of his research, and of the remarkable views to which he had been led regarding the history of species. And as these views could hardly fail in the end to become generally known, it was desirable that the first publication of them should be made by himself. This having been urged upon him by Lyell, he began early in the year 1856 to write out his views in detail on a scale three or four times as large as that on which the _Origin of Species_ afterwards appeared. This work he continued steadily for two years, when it was interrupted (June 1858) by the arrival of a remarkable manuscript essay by Mr. A. R. Wallace, who, working in the Malay archipelago, had arrived at conclusions identical with those of Darwin himself. Darwin's generous impulse was to send this essay for publication irrespective of any claim of his own to priority: but his friends, Lyell and Sir Joseph Hooker, persuaded him to allow extracts from his early sketch of 1844, and part of a letter written to Professor Asa Gray in 1857, to be read, together with Mr. Wallace's contribution, before the Linnean Society, and to be printed in the Society's _Journal_. He now set to work upon that epitome of his observations and deductions which appeared in November 1859, as the immortal _Origin of Species_. Those who are old enough to remember the publication of this work, cannot but marvel at the change which, since that day, not yet thirty years ago, has come alike upon the non-scientific and the scientific part of the community in their estimation of it. Professor Huxley has furnished to the Biography a graphic chapter on the reception of the book, and in his vigorous and witty style recalls the furious and fatuous objections that were urged against it. A much longer chapter will be required to describe the change which the advent of the _Origin of Species_ has wrought in every department of science, and not of science only, but of philosophy. The principle of evolution, so early broached and so long discredited, has now at last been proclaimed and accepted as the guiding idea in the investigation of Nature.