162 Luck, or Cunning ? 
than ever. Nevertheless there is no change in his conclud- 
ing paragraph, which still remains an embodiment of the 
views of Erasmus Darwin and Lamarck. 
The other passage is on p. 421 of the edition of 1876. It 
stands :—‘‘ I have now recapitulated the facts and con- 
siderations which have thoroughly ” (why “ thoroughly ” ?) 
“ convinced me that species have been modified during a 
long course of descent. This has been effected chiefly 
through the natural selection of numerous, successive, 
slight, favourable variations; aided in an important 
manner by the inherited effects of the use and disuse of 
parts ; and in an unimportant manner, that is, in relation to 
adaptive structures, whether past or present, by the direct 
action of external conditions, and by variations which 
seem to us in our ignorance to arise spontaneously. It 
appears that I formerly underrated the frequency and 
value of these latter forms of variation as leading to 
permanent modifications of structure independently of 
natural selection.” 
Here, again, it is not use and disuse which Mr. Darwin 
declares himself to have undervalued, but spontaneous 
variations. The sentence just given is one of the most 
confusing I ever read even in the works of Mr Darwin. 
It is the essence of his theory that the ‘‘ numerous succes- 
sive, slight, favourable variations,’ above referred to, 
should be fortuitous, accidental, spontaneous ; it is evident, 
moreover, that they are intended in this passage to be 
accidental or spontaneous, although neither of these words 
is employed, inasmuch as use and disuse and the action of 
the conditions of existence, whether direct or indirect, are 
mentioned specially as separate causes which purvey only 
the minor part of the variations from among which nature 
selects. The words “ that is, in relation to adaptive forms ” 
should be omitted, as surplusage that draws the reader’s 
attention from the point at issue; the sentence really 
amounts to this—that modification has been effected 
