THE CO-OPERATION OF THE FACTORS. 469 



to live, even with external aid. As the preservation of in- 

 capables is habitually secured by our social arrangements ; 

 and as very few except criminals are prevented by their in- 

 feriorities from leaving the average number of offspring (in- 

 deed the balance of fertility is probably in favour of the in- 

 ferior) ; it results that survival of the fittest, can scarcely at 

 all act in such way as to produce specialities of nature, either 

 bodily or mental. Here the specialities of nature, chiefly 

 mental, which we see produced, and which are so rapidly 

 produced that a few centuries show a considerable change, 

 must be ascribed almost wholly to direct equilibration.* 



* As having an instructive bearing on the question of the varieties of Man, 

 let me here refer to a paper on " The Origin of the Human Races " read before 

 the Anthropological Society, March 1st, 1864, by Mr Alfred Wallace a gentle- 

 man well known among naturalists, as having independently thought out the 

 hypothesis of natural selection, though at a later date, and less elaborately, than 

 Mr Darwin. In this paper, Mr Wallace shows, very clearly I think, that along 

 with the attainment of that degree of intelligence implied by the use of imple- 

 ments, clothing, &c., there arises a tendency for modifications of brain to take the 

 place of modifications of body still, however, regarding the natural selection of 

 spontaneous variations, as the cause of the modifications. But if the foregoing 

 arguments be valid, natural selection here plays but the secondary part of fur- 

 thering the adaptations otherwise caused. It is true that, as Mr Wallace argues, 

 and as I have myself briefly indicated (see Westminster Eevieiv, for April, 1852, 

 pp. 496 501), the natural selection of races, leads to the survival of the more 

 cerebrally-developed, while the less cerebrally-developed disappear, ."3'it though 

 natural selection acts freely in the struggle of one society with another ; yet, among 

 the units of each society, its action is so interfered with, that there remains no ade- 

 quate cause for the acquirement of mental superiority by one race over another, 

 except the inheritance of functionally-produced modifications. This view, how- 

 ever, agrees equally well with Mr Wallace's conclusion, that at a certain stage of 

 evolution, the brain hep-ins to change much more than the 



