Discovery of Leprosy Bacillus

To the Editor:  —In a letter of March 7, 1962, the medical director of the Leonard Wood Memorial (American Leprosy Foundation), James A. Doull, informs me that there are some discrepancies in the American textbooks and manuals concerning the date on which Armauer Hansen first observed the rod-shaped bodies in leprous nodules later known as Mycobacterium leprae (Hansen's bacillus). The date oscillates between 1868 and 1879. Since most of Hansen's publications are written in Norwegian, and very few of the authors of textbooks and manuals are able to read this language, it is understandable that there should be some misapprehension. To prevent these discrepancies from continuing in the future, I will give the following facts.In his first scientific paper in 1869, Hansen gave a description of the normal and pathological anatomy of lymph nodes. It was not printed until 1871.¹ In the material, information regarding some lymph nodes