This monograph stresses the importance of familial susceptibility in the development of active tuberculosis. The conclusions are reached by statistical analysis, and much of the material dealt with has been accumulated through the Williamson County Tuberculosis Study.
This project was undertaken in Williamson County, Tenn., in 1931, with the assistance of the International Health Division of Rockefeller Foundation.
It is stated that more persons from families susceptible to tuberculosis appear to contract the disease than do persons from resistant families and that they have a more severe form. The suggestion is made that familial aggregation of tuberculosis has remained relatively stationary and that the decline in the tuberculosis death rate is due to a reduction in the proportion of tuberculous families in the population. There are interesting observations on the tuberculosis attack rate in children of tuberculous parents. This rate was high up to age 30 when the parent was