cox, DARWIN AND THE MUTATION THEORY 443 



the frequency and importance of modifications due to spontaneous varia- 

 bility," ^ he still later interpolates the following rather sweeping recantation: 



"There are, however, some who still think that species have suddenly given 

 birth, through quite unexplained means, to new and totally different forms; but, 

 as I have attempted to show, weighty evidence can be opposed to the admission of 

 great and abrupt modifications. Under a scientific point of view, and as leading to 

 further investigation, but little advantage is gained by believing that new forms are 

 suddenly developed in an inexplicable manner from old and widely different forms, 

 over the old belief in the creation of species from the dust of the earth." ^ 



In this sixth, and last, edition of the "Origin of Species" Mr. Darwin 

 devoted to the task of answering criticisms made by St. George Mivart far 

 more space than he had ever allowed to any other one critic and the passage 

 just read is evidently one of those inspired by Mr. Mivart's attacks. The 

 sore point with Mr. Darwin at that time was the doctrine of natural selection 

 and, as I have already remarked, he had adopted the erroneous belief that 

 this important principle must be greatly weakened if not entirely sacrificed 

 if any form of saltation was to be admitted in nature. He had, therefore, 

 wavered between his loyalty to his cherished hypothesis and his fearless 

 devotion to truth. By this time, however, he had so long contemplated the 

 possibility of the origin of new species and varieties through single long steps 

 and had had so many convincing examples brought to his attention, that his 

 hesitancy and doubt concerning the validity and sufficiency of the arguments 

 urged in favor of this mode of evolution were ready to give way, and I regard 

 the passage which I am about to quote, as a virtual surrender on this point. 

 The fact that, in this emphatic form, it was written at the close of his life, 

 as his last word on this subject, and that he must haVe felt that it contained a 

 concession very damaging to the theory to the establishment of which that 

 life had been devoted, gives it, in my mind, a deeply pathetic significance. 

 Mr. Darwin says: 



"It appears that I formerly underrated the frequency and value of [variations 

 which seem to us in our ignorance to arise spontaneously] as leading to permanent 

 modifications of structure independently of natural selection. But as my conclusions 

 have lately been much misrepresented, and it has been stated that I attribute the 

 modification of species exclusively to natural selection, I may be permitted to remark 

 that in the fu^st edition of this work, and subsequently, I placed in a most conspicuous 

 position — namely at the close of the Introduction — the following words : ' I am 

 convinced that natural selection has been the main but not the exclusive means of 

 modification.' This has been of no avail. Great is the power of steady misrepre- 

 sentation; but the history of science shows that this power does not long endure." ' 



1 " Origin of Species," 6th ed., 1882, p. 171. 

 2 Ibid., p. 424. 



^ Ibid., p. 421. See also, "Life and Letters," 1886, Vol. III. p. 243, and "More Letters," 

 1907, Vol. I. p. 389. 



