24 MASS STUDIES IN BUILD. 



examined thousands of these records, just as carelessness is revealed 

 also by slipshod speech or posture. 



For our study we desire the data of stature and weight for children, 

 parents, and grand-parents. With some exceptions only those families 

 are studied in which all these data are accurately given. Also, only 

 children who are above 18 years of age can be utilized, because stature 

 changes so rapidly until that age. However, since it is build and not 

 stature we are studying, the fact of increase of stature from 19 to 21 

 years of age affects the result very little. Finally, in a certain propor- 

 tion of the cases the stature and weight of all of the grand-parents 

 are not given quantitatively. Such families are utilized, nevertheless, 

 with such quantitative data as may have been afforded. 



The data were taken from the Records of Family Traits by Miss 

 Miriam Kortright, who long assisted in our statistical work. The 

 computations of index of build were made by Miss Kortright and 

 Mr. William Kraus, Miss Laura Craytor, and Miss Margaret Andrus, 

 who checked one another's work. The tabulation and seriations of 

 the indices were done by Misses Margaret Babcock and Katharine 

 Belzer. 



THE ADULT INDEX OF BUILD. 



In an earlier section of this paper the question of the best index of 

 build has been discussed generally. It was pointed out that many 

 regard it as a truism that build is a relation of volume to stature. 

 Since the volume of a person's body is rarely known, and it is difficult 

 to determine it, weight has been substituted for volume. However, 

 this substitution assumes that specific gravity is the same for slender 

 and for fat persons; but this is not at all the case. The specific 

 gravity of a fat person is about that of water (0.978 to 1.079 in 4 

 children 7 to 13 years of age, Meeh, 1879, and 1.014 in a 61-year-old 

 man of 98 km. weight, Mies, 1899) ; of a thin person it may be 5 to 8 

 per cent above that of water (1.049 to 1.082 for thin convicts, Mies, 

 1899). This variable specific gravity complicates the attempt to 

 infer volume from weight. In view of these difficulties it were better 

 to measure build by a relation of chest diameter (or circumference) 

 to stature. But this ratio can not be used in our studies, since our 

 data, for the most part, give only weight and stature and not chest- 

 girth. It remains thus to determine the closest relation between 

 weight and chest-girth. This determination I have attempted to 

 make for 100 young men, 20 to 25 years of age, measured at Harvard 

 University where they were students. It will hardly be worth while 

 to reproduce the detailed tables of measurements and ratios, but they 

 will be found summarized in table 8. In this table is given the fre- 

 quency of occurrence of each of the different ratios (or rather classes 

 of ratios) found using chest-girth in first, second, and third powers as 



