Anmerkungen:
At head of title: U. S. Treasury department. Henry Morgenthau, jr., secretary. Public health service. Thomas Parran, surgeon general - "The original publication dealing with this subject was prepared by W. C. Rucker ... and issued as Supplement no. 1 to the Public health reports ... A revision of the original articles appeared as Reprint no. 780 from the Public health reports, August 25, 1922, pp. 2053-2058. In 1928 there appeared a revision of Reprint 750. The present article is designed to bring up to date the material which has appeared perviously."--Footnote, p. 1 - Bibliography: p. 6