We begin to obtain a truer insight into the meaning of the curve of a country's birth-rate when we realize that it is in relation with the industrial and commercial activity of the country.[123] It is sometimes stated that a high birth-rate goes with a high degree of national prosperity. That, however, is scarcely the case; we have to look into the matter a little more closely. And, when we do so, we find that, not only is the statement of a supposed connection between a high birth-rate and a high degree of prosperity an imperfect statement; it is altogether misleading. If, in the first place, we attempt to consider the state of things among savages, we find, indeed, great variations, and the birth-rate is not infrequently low. But, on the whole, it would appear, the marriage-rate, the birth-rate, and, it may be added, the death-rate are all alike high. Karl Ranke has investigated the question with considerable care among the Trumai and Nahuqua Indians of Central Brazil.[124] These tribes are yet totally uncontaminated by contact with European influences; consumption and syphilis are alike unknown. In the two villages he investigated in detail, Ranke found that every man over twenty-five years of age was married, and that the only unmarried woman he discovered was feeble-minded. The average size of the families of those women who were over forty years of age was between five and six children, while, on the other hand, the mortality among children was great, and a relatively small proportion of the population reached old age. We see therefore that, among these fairly typical savages, living under simple natural conditions, the fertility of the women is as high as it is among all but the most prolific of European peoples; while, in striking contrast with European peoples, among whom a large percentage of the population never marry, and of those who do, many have no children, practically every man and woman both marries and produces children. If we leave savages out of the question and return to Europe, it is still instructive to find that among those peoples who live under the most primitive conditions much the same state of things may be found as among savages. This is notably the case as regards Russia. In no other great European country do the bulk of the women marry at so early an age, and in no other is the average size of the family so large. And, concomitantly with a very high marriage-rate and a very high birth-rate, we find in Russia, in an equally high degree, the prevalence among the masses of infantile and general mortality, disease (epidemical and other), starvation, misery.[125]