The Fundamental Biological Factors Underlying the Incidence of Tuberculosis.—II

is of the same order in each case as that of any physical inherited character. The correlation between father or mother and child for phthisis is r=0-5, the same as for eye colour, &c., and for members of the same sibship (that is brother and sister), it is about 04 in each case. These refer to completed life histories, but the same is found amongst children. The following data bearing on this point was collected in the area, it refers to the association of lethal tuberculosis in the family, and existance of recognisable pulmonary tuberculosis in a child under 7 and 14 years, the child being in school attendance.