564 PROCEEDINGS OF SECTION G. 
mental dulness or scholastic backwardness. Children who 
are forced to do manual work out of school hours, or who 
are compelled occasionally to absent themselves from school 
to assist their parents in earning their livelihood, are apt 
to acquire manual strength, and to lack mental develop-. 
ment. More interesting is a comparison of the strength 
of the two hands. 
Taking all the children éxamined, at no age does the 
average strength of the left hand exceed that of the right. 
Up to eight years of age there is, however, very little 
difference in the strength of the hands; but after that 
age children begin to show a decidedly greater strength in 
one hand than in the other. 
Taking 1000 cases of boys over 5 years of age, the right 
hand is the stronger in 597 instances, the hands are equal 
in 122, and the left is superior in 181. 
Lower EXTREMITIES. 
The lower extremities of boys present no great peculiarity 
of growth. The average length for each age is shown 
in the table herein inserted, and it will be seen that there 
is very little difference in the proportions which the thigh, 
leg, and foot, bear to one another. For the eleven years 
covered by the observations the length of the thigh is 55-6 
per cent. of the length of the whole lower extremity, and 
the leg 44-2 per cent. The foot is 30°7 per cent. of the 
length of the thigh and leg. Up to 8 years of age the 
growth of the lower extremity is rather slow, between 8 
and 15 years it is more rapid, but after the 15th year the 
growth continues, but at a diminished rate, until the adult 
size 1s reached. 
A comparison of the length of the lower extremities of 
Australian boys with those of British birth would be 
extremely interesting. As already noted, the Australian 
child is the taller, and it is alleged that the main cause 
of this greater relative height arises from a difference in 
the length of the thighs, the Australian being reputed to 
have the longer thigh. To settle the matter satisfactorily 
the measurements would need to be extended beyond the 
age of 164 years, the limit of these tables, as important 
changes take place in males after that age has been passed. 
