congenial to it, and a weeding out of the opposed tendencies; until the former have predominated in the race[110]. We have here a very important principle which we must constantly bear in mind—namely, that not only the physical environment, but also the social environment, may determine the survival of those temperaments and qualities of mind best fitted to thrive in it, and, by handicapping those least fitted to it, may gradually bring the mental qualities of the race into conformity with itself. We shall later see other examples by which this principle is more clearly illustrated. We conclude that, while physical environment may act powerfully upon the minds of individuals, moulding their acquired qualities in the three ways noticed—namely, influencing the mind through bodily habit, through the senses, and through the imagination—there is no sufficient evidence that the acquired qualities so induced ever become innate or racial characters by direct transmission. In those instances in which the racial qualities approximate to these direct effects of physical environment, it may well be because the physical environment has brought about adaptation of the race by long continued selection of individuals, or because it has determined peculiarities of social environment, which in turn have brought about adaptation of the racial qualities by long continued selection. CHAPTER XVI THE RACE-MAKING PERIOD (_continued_) We considered in our last chapter the principal modes in which physical environment affects the character of a people—namely, (1) influence on temperament exerted chiefly through climate acting upon the bodily functions: (2) influence through the senses, exerting secondary effects upon the higher mental processes: (3) direct influence on the imagination. We concluded that these effects become innate in some degree; though whether they are impressed on the race by direct inheritance, or by processes of direct or of social selection, or in all three ways, remains an open question. We distinguished, besides these direct modes of influence, two indirect modes by which physical environment affects the mind and character of a people: (1) by its selective action on individuals apart from its influence upon their minds: (2) by determining occupations and social organisation. We may consider them in turn. It is recognised, as I pointed out above, that the races inhabiting hot moist countries are commonly indolent, while those of the moderately cold and moist climates tend to be extremely active and energetic.