Among the few chemical preparations which have a curative effect in leprosy, first place is taken by oils obtained from the seeds of different members of the plant family of Flacourtiaceae, particularly by chaulmoogra oil, and certain preparations obtained from those oils, the effective components of which are apparently the characteristic unsaturated fatty acids. These oils have apparently a specific influence on the disease process. The importance of chaulmoogra oil in the treatment of leprosy justifies fully the writing of a monograph on this subject. Professor Schlossberger, of the Robert Koch Institute in Berlin, Germany has performed a meritorious piece of work in writing this monograph. He believes that although the treatment is only partly satisfactory, the way of improving it is by correlation of clinical and laboratory investigation. The monograph contains the history of the use of the oils in the treatment of leprosy, which dates back many hundreds