244 Trans. Acad. Sct. of St. Louis. 
of this table with the preceding one is very instructive. The 
continuous increase observed in the Absolute Probable Devi- 
ation has disappeared Indeed the total Deviation at age 12 is 
less than at age 7. An important increase occurs in the years 
18, 14, 15 and 16 in boys and 11, 12, 13 and 14 in girls. Dur- 
ing these four years in each sex, the Physiological Difference 
of the Individual from the Type is greater than at any other 
time. Hence this difference does not increase with the age 
of the Type or with its size. The true relation of the Physi- 
ological Difference is made plain by a comparison of Relative 
Probable Deviation with Relative Annual Increase of Average 
