ACADEMT OF SCIENCES] 

 NO. 3] 



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MEASUREMENTS 

 Head Breadth 



33 



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The height of the head is seen to be practically identical in the old Americans within and 

 those outside of the Academy, and it is very nearly the same in the academicians who are not 

 old Americans. An exceptional development of the brain has evidently no appreciable promo- 

 tive effect upon the height of the head. The head of the academicians has not progressed as 

 much in height as it has in length and breadth. 



An interesting point appears relative to individual variability of the three head measure- 

 ments, as shown by the simple coefficient of variation (Range-average) — the length varies least, 

 the breadth more and the height most, though all this within moderate boundaries. The fig- 

 ures further indicate once more that series of even 100 subjects are not sufficient to show the 

 full range of normal individual variation. The members of the Academy and especially the 

 not old American group, vary less than the old Americans outside, in all probability simply 

 because there are not enough of them in these series to show their whole extent of variation. 

 It has long been my conviction, based on repeated experience, that at least 200 individuals of 

 the same sex and stage of life are needed to give a fairly complete view of the variability of any 

 morphological human character. 



