2o8 LIFE OF PROFESSOR HUXLEY chaP. xv 



motions," he steadfastly refused to be an advocate of the 

 theory, " if by an advocate is meant one whose business it 

 is to smooth over real difficulties, and to persuade when he 

 cannot convince." 



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 se- 

 lective 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 sys- 

 tematic study of embryology." 



As for the repugnance of most men to admitting kin- 

 ship with the apes, " thoughtful men," he says, " once es- 

 caped 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 ap- 

 preciated 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 1 1 lashed itself into a fury over the fact 



