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Scientific Proceedings (131) 



188 (2148) 



Hereditary factors in body build. 



By C. B. DAVENPORT. 



[From the Station for Experimental Evolution, Cold Spring 

 Harbor, N. Y.] 



Some physiologists of nutrition seem inclined to conclude that 

 all obesity is exogenous or nutritional obesity; that any excess 

 of energy of intake over what is required to maintain the tem- 

 perature of the body, and to enable it to do its work, due allow- 

 ance being made for loss in feces and urine, must be stored as 

 body fat. That there are endogenous factors is shown in cases 

 of hypothyroidism and disfunction of some other endocrine 

 glands. But Van Noorden, for example, is inclined to reject 

 heredity as a factor in obesity. It is, indeed, recognized that 

 in some races and in some families the individuals have heavier 

 body build than in others. Thus the Scotch are slender and the 

 Greeks and Eastern Jews are stout. But the racial as well as 

 the familial idiosyncracies in build he would explain on the 

 grounds of what may be called social heredity i. e., the handing 

 on of traditions of feeding. On the other hand the degree of 

 functioning of the endocrine glands is hereditary. 



To see if there are hereditary factors in build, a mass of be- 

 tween 2,000 and 3,000 sets of measurements of build, taken 

 chiefly from random family records was distributed by the indices 

 of build, and the number of individuals possessing each index 

 was determined. This gives Figure 1. Figure 1 is the distribu- 

 tion of build of adults referred to about 50 years of age. These 

 adults are grouped in five large classes : Very Slender, Slender, 

 Medium, Fleshy and Very Fleshy. A similar polygon might be 

 made persons 18 years of age, 14 years, 12 years, 8, 4, and 1 

 year or at birth. The means at these different years would vary 

 — thus from 55 per cent, relative chest at 50 years to 47 per cent, 

 at 12 years and to 67 per cent, at birth. 



A figure was shown of the curve of average relative chest 

 girth from birth to 21 years. There is an ontogenetic change in 

 mean build and, at any age, a variability in build. 



