144 FAMILY STUDIES IN BUILD. 



determine build is sufficient to meet all the facts. In other species of 

 animals we have precisely the same kind of differences between 

 hereditary strains of slender and stout build that we have among 

 humans. Thus, among dogs, the slender greyhound or Dachshund 

 and the robust "Chow"; among horses the Thoroughbred and the 

 stocky Percheron; among swine the "razor-back" and the Berkshire; 

 among poultry the slender Leghorn and the stocky Cochin. Slender 

 and stocky as racial traits appear quite as white and black do and 

 they doubtless have similarly a genetic basis. 



A careful study of the families described in this paper must con- 

 vince anyone, it seems to me, of the importance of the genetic factors. 

 The Fun. family is of a wholly different type from the Thr-1 family. 

 Even if the latter eat more, it is because of a constitutional urge like the 

 constitutional urge that leads the Aberdeen-Angus steer to eat more 

 than the Jersey steer. Very probably the Fun. family metabolizes in a 

 different way from the Thr-1 family, building more protein and less fat. 



In other cases it is not the whole fraternity that is fleshy or slender. 

 This is well illustrated by the Wen. family, where 2 of 8 of the main 

 fraternity are very fleshy and all the others of medium build. We 

 have here to do not merely with a family habit of eating, but a dif- 

 ferential constitution that provides one-quarter of the children with 

 a large appetite that leads them to eat heavily and manufacture fat 

 and provides three-quarters of them with a small appetite that leads 

 them to eat lightly and to manufacture protein instead of fat. Con- 

 stitutional differences in the appetite and method of metabolism are 

 the essential factors; and these are the things that are inherited. Only 

 on such an hypothesis can we account for the clear evidence presented 

 of constitutional factors in build — not always one only, but sometimes 

 three or more acting together to produce the end result of obesity. 



A scientific man, interested in nutrition, who has a build of 3.6 (51) 

 himself and one of whose sisters has a build of 3.1 (44), whereas his 

 4 other sibs have builds of 2.5 to 2.1 (35 to 30), writes that his brother 

 (of medium build, but about 75 inches tall) consumes daily about 

 2,700 calories; he himself and his fleshy sister about 2,500, and the 

 others of his fraternity, who are of medium build, 2,000 to 1,800. He 

 is a professional man, who does a good deal of office or laboratory 

 work. He drinks about 3 to 4 quarts of water per day. His son, who 

 is nearly 11 years of age, weighs just over 120 pounds, is 63 inches tall, 

 and fairly fleshy. Though he is active, "never still a minute," yet he 

 has to be urged to eat, willingly misses a meal, and uniformly declines 

 a second helping; "he eats much less than his 6-year-old cousins, who 

 are actually under size for their age; he has never been a heavy eater 

 from the time he was weaned." This boy, the son of a very fleshy 

 man, seems to afford an example of the easily fattening type in whom 

 the slight excess of calories produces a striking result in build. 



