Need for a definite classification of tuberculosis was recognized early in this century. In 1904, Dr. Edward Livingston Trudeau suggested this need to the National Association for the Study and Prevention of Tuberculosis. There followed, through the intervening years, the formulation of the tentative standards, ending in their final adoption by the National Association in 1913. However, not until 1917 (during the early months of the Framington Health Demonstration) was the first edition of the Diagnostic Standards published. Through the ensuing years, eight other editions have been published; these include complete or partial revisions and several reprintings. In reviewing the various editions, one may follow the evolution of the present day methods of diagnosis and classification of pulmonary tuberculosis.
The ninth edition has undergone complete revision, so that current concepts are embodied, and a chapter on screening classification for mass roentgenographic surveys is added. The increasing use of mass chest