28 OBSERVATIONS AND MEASUREMENTS ACADEMY MEMBERS [MEMOI [vo? xxnii 



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Arrnspread in Percentage of Stature 



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The old Americans and the not old Americans in the Academy show much the same con- 

 ditions, and the old Americans at large stand close by. The slight differences that do occur in 

 the ratio are not however, I think, accidental. Mathematical insignificance does not necessarily 

 mean also biological insignificance; but the differences are probably due to age. The influence 

 in this connection of the factor of age will be seen from table 25. 



There appears no difference in the relation of the arm spread to stature in the old American 

 series, and but a small one in the not old American. This should not be taken for evidence 

 that there are no changes. As has been shown there are material changes with age in stature 

 and thus the above showing can only signify that parallel changes take place in the parts that 

 enter into the arm-spread dimension. 



Resume on the Body. — So far as the main proportions of their bodies are concerned, the data 

 show the following characteristics and differences from the old American stock at large: 



The two groups within the Academy, those of old American and those of more recent Euro- 

 pean derivation, show remarkable similarities with only secondary differences. 



Both differ from the old Americans at large in (1) even a higher stature, (2) greater absolute 

 as well as relative weight, and (3) slightly shorter arms relatively to stature. 



