242 Trans. Acad. Sct. of St. Louis. 
ured at each age is also stated, in order to secure a more 
accurate general view. It is seen that the total Absolute 
Probable Deviation increases continuously from age 6 to age 
16 in boys and from age 6 to age 15 in girls (except at age 
8), after which periods there is a fall. The increase is not 
uniform, becoming suddenly much greater at age 13 in boys 
and age 11 in girls, the accelerated increase extending over 
four years in both sexes and ending as suddenly as it began. 
It has been already said that the Absolute Probable Devia- 
tion is entangled with the size of the individual. In Table 
No. 4 this obstacle has been removed and the Physiological 
Difference of Individual from Type appears. A comparison 
