112 CARNEGIE INSTITUTION OF WASHINGTON. 



movements of the population to cotton mills and coal-mining fields, and con- 

 ferences were held with mill superintendents as to source of supply of their 

 workers. The need for certain special studies was urged, such as the Indian- 

 negro-white crosses in the Blue Ridge of Virginia and the Croatans of the 

 coast of the Carolinas. 



The first field work was carried out with an Indian-negro-white cross in 

 Amherst County, Virginia, in collaboration with the Department of Soci- 

 ology of Sweet Briar College, whose students carried on field work under the 

 immediate supervision of Professor I. E. McDougle. About 500 members of 

 this Amherst group have been located and more or less studied. 



The major field operation was started in February 1923, in the mountains 

 of eastern Kentucky, in Leslie County, and is being continued. This area 

 was selected because of its inaccessibility; no railroads enter the county and 

 no industrial development has taken place in it. The county is without 

 improved roads, so that all travel is on horse or mule back, mainly in creek 

 beds. A saddle horse has been purchased by the Department for use of 

 Dr. Estabrook. There are about 25 main families in the county, nearly all 

 dating back to 1800 and coming of hunting stock. Much intermarriage 

 has occurred, little immigration since 1800, but considerable emigration in 

 consequence of the Civil War and the call of the coal mines. A study is being 

 made of these old families. 



'Heredity of Body-Bxjild. 



The Director's paper on this subject is being printed by the Institution. 

 In it two types of variation in build are distinguished, the ontogenetic and 

 the adult. The ratio of chest-girth to stature is regarded as the best index 

 of build; and, where chest-girth is unknown, for adults, weights stature'. 

 Racial, geographical, and ontogenetic differences in build are discussed. 

 Changes in adult build with age are relatively greater in families character- 

 ized by obesity. The mass polygon of distribution of build shows two modes 

 at all ages, evidence of at least two biotypes of build. Slenderness is asso- 

 ciated with tendency toward tuberculosis, pneumonia, nervousness, melan- 

 cholia. Slender parents have smaller families than fleshy ones, and their 

 children show less regression toward mediocrity than those of fleshy parents, 

 and they are less variable, suggesting that there are recessive genes for 

 slenderness carried by the fleshy. There is a marked tendency for persons 

 of similar build to intermarry. Not all persons of the same build are gameti- 

 cally alike. Some slender parents carry 1, others 2, zygotic factors for build. 

 Some parents of medium build are heterozygotes; others belong to a medium- 

 build biotype. The Fi generation derived from a slender X fleshy mating 

 is quite variable, as is commonly found where multiple factors are concerned. 

 Its mode is fleshy, indicating partial dominance of that condition. The F2 

 generation is still more variable than the Fi. The back-cross of a heterozy- 

 gous parent with either parental type tends to fall into heterozygous build 

 and the build of the particular parental type to which the back-cross is made. 



It is considered that variations in build are not to be accounted for merely 

 by variations in the relation of intake and outgo of calories, but also by the 

 endogenous factors that determine "economy of nutrition" or the cost in 

 energy of adding an additional kilogram of weight to the body. Hereditary 

 factors are involved in producing such differences and probably work through 



