‘I am astonished and rejoiced at the progress which the subject has made,’ and went on to give a classified list of his adherents:
| Geologists | Zoologists Palæontologists |
| Lyell Ramsay Jukes H. D. Rogers |
Huxley J. Lubbock L. Jenyns (to large extent) Searles Wood |
| Physiologists | Botanists |
| Carpenter Sir H. Holland (to large extent) |
Hooker H. C. Watson Asa Gray (to some extent) Dr. Boott (to large extent) Thwaites |
And he added that should the book be forgotten in ten years (according to the prophecy of an eminent naturalist), ‘with such a list I feel convinced the subject will not.’ Later on, in May, he wrote full of hope to the same friend: ‘If we all stick to it we shall surely gain the day. And I now see that the battle is worth fighting.’ Later, again, after the adverse reviews in the ‘Edinburgh’ and ‘North British Review,’ and in ‘Fraser's Magazine’ and several others, he saw that the fight was thickening, and wrote to Lyell (1 June): ‘All these reiterated attacks will tell heavily; there will be no more converts, and probably some will go back. I hope you do not grow disheartened. I am determined to fight to the last.’
The second edition of the ‘Origin of Species’ (three thousand copies) was published on 7 Jan. 1860, and two days later Darwin began looking over his notes in preparation for a new book, which should deal in detail with the evidence yielded by domestic animals and plants under cultivation. This book, ‘The Variation of Animals and Plants under Domestication,’ was not published until 1868. But the eight years which elapsed between its commencement and completion were not entirely given up to it. He reckoned that about four years out of this period were employed on it, the working days of the remaining four years being spent in various ways; for instance, on new editions of the ‘Origin,’ and on his books on ‘Orchids’ and on ‘Climbing Plants,’ &c. It will be convenient to treat the botanical work separately, and to consider now the series of books which are more directly connected with the ‘Origin of Species.’
The ‘Variation of Animals and Plants’ was, like all Darwin's books, far more successful than the author expected. His letters contain more than one warning, even to scientific friends, that they must not attempt to read it all, that it is unbearably dull, that if they read the large print in two or three of the chapters they will have all that is worth reading. The most novel point in the book, and the one which had the strongest hold on the author's mind, or at least on his imagination, was the theory of Pangenesis. This theory of the mechanism of inheritance has never met with much acceptance, though some few naturalists have felt, as Darwin most strongly felt, that it was an ‘immense relief’ to have some purely material conception, about which the facts of inheritance can be grouped. Writing in 1876, Darwin said of his theory: ‘If any one should hereafter be led to make observations by which some such hypothesis could be established, I shall have done good service.’ The book did not escape adverse criticism. It was said, for instance, that the public had been patiently waiting for Mr. Darwin's pièces justificatives, and that after eight years all that he had to offer was a mass of details about pigeons and rabbits. But the fair critics saw its true character, an expansion, with unrivalled wealth of fact, of a section of the ‘Origin of Species.’
The ‘Descent of Man,’ which followed in 1871, grew out of the book on ‘Variation.’ It was his original intention to give a chapter on Man, as the most domesticated of animals. But it soon became evident that a separate treatise must be given to the subject. In the ‘Origin of Species’ he thought it best, ‘in order that no honourable man might accuse’ him of concealing his views, to add that ‘light would be thrown on the origin of man and his history.’ The belief that man must be included with other animals had been accepted by him from the first, so that his collection of facts bearing on the subject dated back to 1837 or 1838. This matured store of facts and thoughts could now be fully expanded, and it should be noted that this subject and the variation of domestic races were the only ones connected with evolution which he was enabled to write in extenso, so as to use his full store of materials. In the years between 1859 and 1871 a great change in the receptivity of the public for evolutionary ideas had been wrought, and although the subject was more likely to give offence, yet the ‘Descent of Man’ was received with less than followed the publication of the ‘Origin of Species.’
