of steam-power to the growth of a faculty for understanding the uses of steam. Iiis 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 possess 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 appropriate stimulation, which has developed the knowledge in our minds, was wanting to them. Many negroes, when instructed, have shown themselves capable 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 appeared 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, Mr. 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 therefore be attributed to some other cause, which he thinks can only be spiritual. We have seen that when the nervous 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.e. the products of the functional activities of the
