Appendix II. 325 



Here is another passage to the same general effect. In 

 alluding to the objection from inutility as advanced by 

 Bronn, Broca, and Nageli, Mr. Darwin says : — " There is 

 much force in the above objection"; and, after again 

 pointing out the important possibility in any particular 

 cases of hidden or former use, and the action of the laws of 

 growth, he goes on to say, — " In the third place, we have 

 to allow for the direct and definite action of changed con- 

 ditions of life, and for so-called spontaneous variations, in 

 which the nature of the conditions plays quite a sub- 

 ordinate part '." Elsewhere he says, — " 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 \" The " forms of 

 variation " to which he here alludes are " variations which 

 seem to us in our ignorance to arise spontaneously"; and 

 it is evident that such variations cannot well " arise " in 

 two or more species of a genus similarly and simultane- 

 ously, so as independently to lead " to permanent modifica- 

 tions of structure " in two or more parallel lines. It is 

 further evident that by " spontaneous variations " Darwin 

 alludes to extreme cases of spontaneous departure from 

 the general average of specific characters ; and therefore 

 that lesser or more ordinary departures must be of still 

 greater " frequency." 



Again, speaking of the principles of classification, 

 Darwin writes : — 



" We care not how trifling a character may be — let it be the 

 mere inflection of the angle of the jaw, the manner in which 



In criticising that paper in Nature (vol. xxxix. p. 127), Mr. Thiselton 

 Dyer says of my interpretation of this passage, " the obvious drift of this 

 does not relate to specific differences, but to those which are charac- 

 teristic of family." But in making this remark Mr. Dyer could not 

 have read the passage with snfiScient care to note the points which I have 

 novir explained. 



' Origin of Species, p. 171. " Ili^d. p. 421. 



