═══════════════════════╤═══════════╤═══════════╤═══════════╤═══════════ Age │ 13 │ 14 │ 15 │ 16 ───────────────────────┼───────────┼───────────┼───────────┼─────────── Non-laboring class │ 28.41│ 29.65│ 30.72│ 33.08 Artisan class │ 25.24│ 26.28│ 27.51│ 28.97 ───────────────────────┼───────────┼───────────┼───────────┼─────────── Difference │ 3.17│ 3.37│ 3.21│ 4.11 ═══════════════════════╧═══════════╧═══════════╧═══════════╧═══════════ It will be seen, therefore, that the children of the non-laboring class at thirteen years of age exceed those of the artisan class in height almost three inches, in weight almost ten and a half pounds, and in chest girth almost three and a quarter inches. And these figures by no means represent fully the contrast in physique which exists between the very poorest and well-to-do children. The difference between the children of the best-paid artisans and the poorest-paid of the same class is nearly as great. Mr. Rowntree found that in York, England, the boys of the poorest section of the working-class were on an average three and one-half inches shorter than the boys of the better-paid section of the working-class. As regards weight Mr. Rowntree found the difference to be eleven pounds in favor of the child of the best-paid artisan.[58] Dr. W.W. Keen quotes the figures of Roberts with approval as applying almost equally to this country,[59] and all the studies yet made by American investigators seem to justify that opinion. There exists a somewhat voluminous, but scattered, American literature tending to the same general conclusions as the European. The classic studies of Dr. Bowditch,[60] in Boston, and Dr. Porter,[61] in St. Louis, showed very distinctly that the children of the poorer classes in those cities were decidedly behind those of the well-to-do classes in both height and weight. The more recent investigations of Dr. Hrdlicka[62] fully bear out the results of these earlier studies.