H. R. Schinz, professor of roentgenology in Zurich, in a prefatory word points out that the study of genetics is yet in its infancy and that an intensive study of human heredity did not begin until after the World War. He points out further that the study of twins is the most certain method for determining some of the relations between inherited and acquired characteristics.
Buschke, the author, says that the skeleton is in many respects a mirror by means of which the biologic changes in the organism can be read. The roentgen-morphologic analysis of the skeleton, especially of the growing skeleton, gives perhaps more exact information about the variations in the function of the endocrine organs than can be obtained in any other way. The author's purpose is to determine to what extent hereditary factors influence the development and individual form of the skeletal system. He presents the results