In a second and perhaps even more important way, the formation of nations with the development of civilisation modified and weakened the moulding influence of the physical environment; namely, it introduced social co-operation in an ever increasing degree, so that the perpetual struggle of individuals and of small family groups with one another and with nature was replaced by a co-operative struggle of large communities against the physical environment and with one another. And in this process those members of each community who, by reason of weakness, general incapacity, or other peculiarity, would have been liable to be eliminated under primitive conditions became shielded in an ever increasing degree by the powers of the stronger and more capable against the selective power of nature and against individual human forces. And, although within the community the rivalry of individuals and families still went on, it was no longer so much a direct struggle for existence, but rather became more and more a struggle for position in the social scale; and failure in the struggle no longer necessarily meant death, or even incapacity to leave an average number of descendants. That is to say, primitive man’s struggle for existence against the forces of nature and against his fellow men, which made for racial evolution and differentiation through survival of those fittest to cope with various environments, tended to be replaced by a struggle which no longer made for racial evolution towards a higher type, and which may even have made for race-deterioration, at the same time that civilisation and national organisation continued to progress. We may, then, recognise a certain truth in Bagehot’s distinction of two great periods, the race-making and the nation-making periods. Nevertheless, it would not be satisfactory to follow the course suggested above and simply assume certain racial characters as given fixed data without further consideration. For, firstly, it is interesting and perhaps not altogether unprofitable to indulge in speculations on the race-making processes of the prehistoric period. Secondly, although it seems likely that racial changes have been in the main slower and on the whole relatively slight in the historic period, yet they have not been altogether lacking; and, in proportion to their magnitude, such changes as have occurred have been of great importance for national life; and changes of this kind are still playing their part in shaping the destinies of nations. Possible racial changes of mental qualities must therefore be considered, when we seek to give a general account of the conditions of the development of nations.