While man's reproductive power is slight from the standpoint of bacteria and conger-eels, it is yet far from negligible, as is shown by the birth-rate of the less-advanced human types at all times, and by the birth-rate of the higher types under exceptionally favorable circumstances. The nineteenth century was one of these favorable occasions. In the new areas of settlement outside Europe, vast regions practically untenanted by colored competitors invited the white colonists to increase and multiply; while Europe itself, though historically "old country," was so transformed environmentally by the industrial revolution that it suddenly became capable of supporting a much larger population than heretofore. By the close of the century, however, the most pressing economic stimuli to rapid multiplication had waned in Europe and in many of the race dependencies. Therefore the rate of increase, even under the most favorable biological circumstances, should have shown a decline. The trouble was that this diminishing human output was of less and less biological value. Wherever one looked in the white world, it was precisely those peoples of highest genetic worth whose birth-rate fell off most sharply, while within the ranks of the several peoples it was those social classes containing the highest proportion of able strains which were contributing the smallest quotas to the population. Everywhere the better types (on which the future of the race depends) were numerically stationary or dwindling, while conversely, the lower types were gaining ground, their birth-rate showing relatively slight diminution. This "disgenic" trend, so ominous for the future of the race, is a melancholy commonplace of our time, and many efforts have been made to measure its progress in economic or social terms. One of the most striking and easily measured examples, however, is furnished by the category of race. As explained in the Introduction, the white race divides into three main sub-species--the Nordics, the Alpines, and the Mediterraneans. All three are good stocks, ranking in genetic worth well above the various colored races. However, there seems to be no question that the Nordic is far and away the most valuable type; standing, indeed, at the head of the whole human genus. As Madison Grant well expresses it, the Nordic is "The Great Race."