706 TRANSACTIONS OF SECTION L. 
A good rough estimate of the manner in which a boy is thriving can be formed 
by comparison of periodic measurements of his height and weight. In order that 
the lesson to be learnt from these observations may be sufficiently obvious a 
system of grades is required. Comparison with the rate of growth of the mean 
boy is unsatisfactory ; a high-grade boy of fourteen will normally grow twice as 
fast as a low-grade boy, while at eighteen the low-grade boy should be growing 
twice as fast as the high-grade hoy. 
I have used for some years a set of tables by means of which the height and 
weight of all boys observed may be referred to one or other of twenty grades—all 
equally probable—of which grade 1 is the highest, The record of a boy’s growth can 
conveniently be kept upon a form divided by parallel lines into twenty spaces to 
represent the twenty grades, separate graphs being drawn for height and weight. 
These graphs will be fairly level in rather more than 50 per cent. of the cases 
observed. In the majority of the remaining cases periods of steady rise or fall 
will be noted in which the two graphs, as a rule, remain fairly parallel. In some 
cases the graphs are very irregular, constant fluctuations being apparent. In such 
cases the fluctuations in the two graphs are generally found to correspond. 
Consecutive observations will give the same grade in about 50 per cent. of the 
cases observed. The graph normally rises in 25 per cent. and falls in 25 per cent., 
speaking roughly. Any disturbing cause will alter these proportions in a group 
affected by it; e.g., in a school in which observations are recorded in March, June, 
and October or November I found that in the various intervals the percentages 
were :— 
In Height, Up Level | Down 
March to June . : c¢ 7 = 25°4 53'0 | 21°6 
June to October . A : ; A aie hall 45:7 | 21:2 
November to March . : ; 4 14-2 47:3 38°6 
In Weight Up Level Down 
March to June . : 3 : . 33°5 41°2 25°4 
June to October . : : : : 359 41°6 22°7 
November to March . : ; 24:4 37°6 38:0 
Variations in chest-girth are far more marked than those in height and 
weight, the chief disturbing factor being systematic physical training. Thus of 
225 Haileybury boys—taken as they came—who were measured on entrance, and 
again after three terms of compulsory physical training, one boy improved 15 grades 
in chest-girth, three boys 13 grades, four boys 12 grades; 12 per cent. had gone 
down from 1 to 5 grades, 14 per cent. were level, 50 per cent. had improved from 
1 to 5 grades, 15'5 per cent, from 5 to 10 grades, and 85 per cent. had improved 
more than 10 grades. 
Typical schemes of development may be arrived at by working out the average 
grades of the type required. E.g., Typical Athletes grade at 7 in height, 5 in 
chest-girth, 3 in weight, and are early developed. Typical Gymnasts grade 13 in 
height, 7 in weight and chest-girth, the grade of height being very uniform 
throughout their scheme of growth. Typical Scholars grade 9 in height and 
chest-girth, 7 in weight. The importance of weight as a sign or factor of vigour 
is very marked. 
For general use I would urge that a system of percentile grades be adopted, 
which should include all classes of the population. In order to construct such a 
system we require a large number of accurate observations, which must include 
children of all ages, subject to every variety of condition as regards nurture and 
environment. 
