This is the sixth edition of this well known standard textbook. New material has been added to the sections on tuberculosis, diphtheria, Vincent's angina, insectborne diseases and quarantine, and the parts on venereal diseases, sex hygiene, heredity, eugenics, deficiency diseases and occupational diseases have been rewritten. New subjects considered for the first time are contraception, maternal mortality, heart disease, diabetes, ringworm, snake poisoning, psittacosis, periodic health examinations and hospitals. It is unnecessary to eulogize such an excellent textbook; the work speaks for itself. This new edition brings the field of preventive medicine entirely up to date in the well written manner begun in the first edition. The book should have a place in every physician's library.