162 Trans. Acad. Sci. of St. Louis. 
regulation of mental labor from a physical standpoint is 
a venturesome groping rather than a scientific deduction. 
The rational basis for this far-reaching reform in school 
hygiene is fast being laid. Foreign governments are making 
extended anthropometric measurements of children of all 
ages, and in our own land private enterprise and zeal for 
the advancement of learning have borne the burden of inves- 
tigations that should be matters of public concern. Indeed, 
it is an American physiologist, Henry P. Bowditch, to whom 
must be given the honor of having first measured weights 
and heights of boys and girls in numbers sufficiently large 
to fix with certainty the general laws of growth. 
It is evident that a due regard must be paid to exceptions 
in the application to special classes of laws true only of the 
mean of all classes at each age in the period of development. 
The dull and the precocious constitute such special classes. 
It is therefore of the highest interest and importance to 
determine whether dullness and precocity are associated with 
a physical variation from the mean so palpable that it can be 
recognized by the coarse methods of investigation practicable 
in school work. 
Of these methods, none is more useful than weighing, 
partly because it is easy to weigh and partly because the 
weight has a very close relation to strength. The weight 
in fact may be looked upon as an index of physical develop- 
ment. By weighing then may be answered the questions: 
Are dull children in the mean weaker and precocious children 
in the mean stronger than the average child? Is there 4 
physical basis for precocity and dullness? Is mediocrity 
of mind associated in the mean with mediocrity of physique? 
All these questions must be answered in the affirmative, and 
I will now ask you to examine the method by which this 
answer has been reached. : 
The course of study in the Public Schools of St. Louis 15 
divided into eight grades, of which tbe first is the lowest. 
To these must be added the kindergartens and the High 
School, including the relatively small Normal School for the 
training of women to be teachers. Children are admitted = 
the kindergartens at six years. Some pupils will be found in 
