Three editions of this work have been exhausted within the last eight years, and this, the fourth, is required to meet the continued demand. Prof. Mairch is so well known to students, pharmacists and physicians that his work has little need of commendation. The physical characters of drugs are well described, but the more important feature, and which gives special value to the book, is his effort, so far as present experience will permit, to clearly set forth the medical properties of the proximate principles of medicines, and to clearly set forth the effects of solvents in order to determine for each its proper menstruum, and also to carefully avoid incompatibilities. The work bears evidence of careful revision, and contains the results of the latest investigations in this important branch. The materia medica of the western continent will yet require a vast amount of careful investigation, and the present work