This volume, which, as its title page shows, is substantially the same as the Alvarenga Prize Essay for 1898, is probably the best general statement of its subject now extant. In the flood of literature on tuberculosis at the present time, it is well to have a fair, scientific, standard monograph on the subject, and this comes as nearly meeting this demand as any work that has yet appeared. It has, moreover, the very great advantage of being written in a readable and technical style, so that it is in its present form available as a semipopular treatise on its subject. While some opinions here expressed may be modified with advancing knowledge, the author is generally on the safe side, which is a merit in a work of this kind. Another merit is the usual avoidance of extreme statements or the advocacy of such measures as would work serious hardship