We can draw another parallel between large groups of people who show very marked differences in physical development, due, we believe, primarily to the differences in the quality of their diets. In Sweden in 1900 there was approximately one dairy cow to every two inhabitants. A similar relation is held in Switzerland with respect to the development of the dairy industry in relation to population. On the other hand the Southern United States had but one cow to five to ten or more people. There are no places in Europe where more hardy and aggressive men and women are to be found than in Scandinavia and in Switzerland. In marked contrast stand health conditions in the Southern States, as is shown, among other ways, in the high incidence of pellagra, which Gold-berger has demonstrated, is directly attributable to inadequate diet. Like many other lines of evidence, we cannot push too far our contrasts of this character, because other factors can be readily suggested to account in a satisfactory manner for observed facts. Human subjects do not as a rule restrict themselves to one-sided diets to a degree which leads to unequivocal and extreme conditions corresponding with the results of animal experimentation. The parallels which we have drawn, do, however, correlate so well with the results of studies on animals as to leave little room for denial of their justification.