Having thus laid before you the general lines on which I propose to deal with problems relating to race and nationality, I propose now that we should make a lightning trip round the world and cull, as we go, samples which will illustrate the kind of friction which arises wherever races or nationalities come into close contact. As I have already said, every country can yield us material for our study, but none on such a vast experimental scale as the United States of North America; we shall therefore commence our hurried survey in that country. Within the frontiers of the States is massed a population of 110 millions. When we look closely we see that over ten millions of these inhabitants are marked off from the rest by a frontier, a colour line, as sharply defined and jealously guarded as the frontiers of a kingdom. Across that racial frontier all legitimate social traffic is barred, the custodians of the frontier being those who stand on the white side of the line. Any attempt to cross that racial frontier produces mob war. While these ten millions of segregated citizens abide within their racial fence, they see millions arrive from Europe and pass freely through the national and social gateways--which for them are barred. In the course of a generation they see these new arrivals, men, women, and children born and bred within the diverse nationalities of Europe, differing markedly in appearance and speech from the original colonial stock, become slowly stript of their alien outlook and gradually incorporated within a new national mass. In the States, then, we see a machinery at work which maintains racial frontiers but breaks down all national barriers. The nature of that machinery we shall have to inquire into later, but in the meantime I will briefly define the essential difference between a racial and a national frontier. A marriage across a racial frontier gives rise to an offspring so different from both parent races that it cannot be naturally grouped with either the one or the other. A marriage across a national frontier gives rise to a progeny which may pass as a member of either parent nationality. Further, as I shall attempt to prove later, nationality is the incipient stage in the process which leads on to racial differentiation. PROBLEMS OF CANADA