[In common fairness he warned his audience of the one missing link in the chain of evidence--the fact that selective breeding has not yet produced species sterile to one another. But it is to be adopted as a working hypothesis like other scientific generalisations,] "subject to the production of proof that physiological species may be produced by selective breeding; just as a physical philosopher may accept the undulatory theory of light, subject to the proof of the existence of the hypothetical ether; or as the chemist adopts the atomic theory, subject to the proof of the existence of atoms; and for exactly the same reasons, namely, that it has an immense amount of prima facie probability; that it is the only means at present within reach of reducing the chaos of observed facts to order; and lastly, that it is the most powerful instrument of investigation which has been presented to naturalists since the invention of the natural system of classification, and the commencement of the systematic study of embryology." [As for the repugnance of most men to admitting kinship with the apes,] "thoughtful men," [he says,] once escaped from the blinding influences of traditional prejudices, will find in the lowly stock whence man has sprung the best evidence of the splendour of his capacities; and will discern, in his long progress through the past, a reasonable ground of faith in his attainment of a nobler future." [A simile, with which he enforced this elevating point of view, which has since eased the passage of many minds to the acceptance of evolution, seems to have been much appreciated by his audience. It was a comparison of man to the Alps, which turn out to be] "of one substance with the dullest clay, but raised by inward forces to that place of proud and seemingly inaccessible glory." [The lectures were met at first with astonishing quiet, but it was not long before the stones began to fly. The "Witness" of January 11 lashed itself into a fury over the fact that the audience applauded this "anti-scriptural and most debasing theory...standing in blasphemous contradiction to biblical narrative and doctrine," instead of expressing their resentment at this "foul outrage committed upon them individually, and upon the whole species as 'made in the likeness of God,'" by deserting the hall in a body, or using some more emphatic form of protest against the corruption of youth by "the vilest and beastliest paradox ever vented in ancient or modern times amongst Pagans or Christians." In his finest vein of sarcasm, the writer expresses his surprise that the meeting did not instantly resolve itself into a "Gorilla Emancipation Society," or propose to hear a lecture from an apostle of Mormonism; "even this would be a less offensive, mischievous, and inexcusable exhibition than was made in the recent two lectures by Professor Huxley," etc.] Jermyn Street, January 13, 1862. My dear Darwin,