Physical Measurement of Public Schoolboys

Abstract

I ENCLOSE photographs of two lecture diagrams which were used for a paper on the physical development of public schoolboys read to the Medical Officers of Schools Association last Easter. The curves represent the various different schemes of growth followed by schoolboys from the age of 10½ to 18½, according as they are developing into large, small, or medium sized men. They are constructed from corresponding series of curves of distribution, which curves are constructed from a large number of observations recorded at various public schools. From 14,000 to 15,000 observations have been collated for the construction of each series, and I regard them as being fairly trustworthy in form between the ages of 12 and 18. Beyond these limits the form of the curves may be slightly at fault, owing both to insufficient number of observations and to the process of natural selection which influences the physical status of the majority of boys who come early and stay late at a public school. The curves in Fig. 1 are constructed by marking off on the vertical line through each age the various heights at which the curve of distribution for that age crosses the 5 per cent., 10 per cent., 15 per cent., … 95 per cent, lines. Each series of corresponding points is then joined up by a flowing curve, with the result shown. The central line, between the numbers 10 and 11, shows where the various curves of distribution cross the 50 per cent, line, and consequently indicates the scheme of growth of the mean boy.