ORGA?^IC EVOLUTION — MENTAL 167 



of steam-power to the growth of a faculty for uuder- 

 standing the uses of steam. His greater knowledge is 

 certainly due solely to the circumstance that he has 

 been the recipient mentally of appropriate stimulation 

 which was wanting to the ancients ; in other words, that 

 he has been taught that which they more painfully 

 discovered. When therefore we read in books of travel 

 that the individuals of this or that tribe of savages pos- 

 sess no knowledge of numerals or of music, we are not 

 to suppose, as travellers commonly do, that they are 

 incapable of acquiring the knowledge, but only that 

 the apjjropriate stimulation, which has developed the 

 knowledge in our minds, was wanting to them. Many 

 negroes, when instructed, have shown themselves cap- 

 able of high mathematical attainments, and the whole 

 race in America is notoriously musical. I myself have 

 heard, in Honolulu, a Kanaka band, which I was told was 

 of great excellence, and the Maoris of New Zealand ap- 

 peared to me fully equal in powers of mind to average 

 Europeans, though far surpassed by the latter in actual 

 knowledge. 



As evidence that the mathematical, musical, and 

 artistic faculties have not resulted from the action of 

 Natural Selection, ]\Ir. Wallace points out that 

 individuals vary to an extraordinary extent as regards 

 these powers, a small minority having a thousand-fold 

 greater endowment than average humanity. The 

 powers of these gifted beings, he says, are plainly not 

 attributable to the survival of the fittest, and must there- 

 fore be attributed to some. other cause, which he thinks 

 can only be spiritual. We have seen that when the ner- 

 vous systems of two allied species of insects — e. g. ants — 

 appear precisely similar, there is often a vast difference 

 mentally in some one or other particular ; on the whole, 

 their nervous systems subserve much the same purposes 

 — i. c. the products of the functional activities of the 



