CHAPTER VIII. 
THE RELATION BETWEEN THE PHYSICAL DEVELOPMENT OF SCHOOL 
HILDREN AND THEIR CAPACITY FOR MENTAL LABOR. 
In Vol. VI, No. 7 of the Transactions of the Academy of 
Science of St. Louis, issued March 21, 1893, I demonstrated 
that children who possess more than the ordinary power of 
mental labor, as measured by their progress in their studies, 
are heavier, taller and larger in girth of chest and in width of 
head than their less gifted companions of the same age. A 
more extended statement of these observations was presented 
to the Berliner Gesellschaft fiir Anthropologie, Ethnologie 
und Urgeschichte, July 15, 1893, and appears in Virchow’s 
Zeitschrift fiir Ethnologie under the title Untersuchungen der 
Schulkinder in Bezug auf die physischen Grundlagen ihrer 
geistigen Entwickelung. In these papers, the material was 
the total number of observations irrespective of the social 
condition of parents. An example, selected from Tables Nos. 
2 and 4, page 165 and 167, of The Physical Basis of Pre- 
cocity and Dullness, will illustrate the result of the © 
inquiry. Pupils aged 11 are found in Grades I, II, UI, IV, 
V and VI of the St. Louis Public Schools, as the following 
table shows. The 59 boys of GradeI, the lowest grade, 
TABLE No. 35. 
MEDIAN WEIGHT OF BOYS AGED 11 DISTRIBUTED BY SCHOOL GRADE. 
No. of Boys Median 
Grades. Weighed. Weight. 
Picts cise besa nuhlnewak dee h iW) bea eee an en NenEeS 59 28.83 Kg 
Bb vdohes nueva niep dba dvncenwabey eeh cee eee 811 29.74 *§ 
SET yo vxceseesendgstuei ii nvew eee eee 664 30.92... °° 
EV ovo els Shas 0k ewe lbscubede eter see 546 31.43". ** 
Vice se cwor de Coane guavil Clete een eeeeeees 123 o2.4b> * 
Vins nsida vd twee veencdonaseuy week enuerEeabyeeewers 33 33.29. ** 
weigh less than the boys of Grade II, and these, again, are 
lighter than the boys in higher grades. 
(335) 
