We may, then, profitably consider such synthetic problems as suggest themselves. Among these, by far the most popular, are those dealing with the origins of New World peoples and their culture, their relation to the races of the Old World, and the antiquity of their arrival in the New. These subjects have been many times discussed, but they are here considered as interpretations based upon empirical classifications of scientific data.
As we proceed, the reader will become conscious of a certain asymmetry in the descriptive chapters, but this is unavoidable, for it so happens that we have much more complete data for the United States and Canada than for other parts of the New World. For South America, in particular, the data are quite unsatisfactory. Consequently, most of the illustrative examples and the inductive interpretations in this book are drawn from the best known parts of North America. On the other hand, the data at large are sufficient to reveal the main characteristics of the whole New World and to make clear the fundamental unity that exists throughout. In addition, the limitations of space have necessitated passing over many topics in silence. For example, we have omitted all discussions of warfare and fighting customs, chiefly because these are the most familiar to general readers. Moreover, these subjects are rather fully treated in historical books and tales of adventure, but the reader who wishes to go deeper into the problem may, with profit, consult the writings of Bandelier and Friederici. Another very important point that might be considered is the density of native populations in pre-Columbian times, a subject we should have gladly made room for if there were available reliable estimates. Recently this problem has been taken up by Mr. James Mooney, who is now preparing a publication on the subject. However, when we take into account the modes of life followed in the different areas, it appears a fair assumption that in 1492 the native population was about at its maximum; that is, the hunting areas contained as many people as the fauna would support and the agricultural areas about all that could be provided for under the existing systems. Yet, this may prove an error