This, the sixth edition of Dr. Butler's book, contains but few changes from and additions to the previous edition; those that have been made, however, add to its value. In the new edition we find grindelia classed as a "Motor Depressant," balsam of Peru under the "Aromatic Acids," tar and balsam of tolu as "Drugs Acting on the Respiratory Membranes," while buchu, uva ursi, juniper, copaiba, oil of santal, cubeb and sabal are found under "Drugs Acting Particularly on the Kidneys." In the previous edition all of these drugs were lumped together under the "Group of Aromatics Used Particularly to Stimulate the Mucous Membranes of the Genitourinary or Respiratory Tract." The new arrangement is obviously more rational. We also find that opium, which in the fifth edition was classed under "Hypnotics," is now found more correctly under the "Narcotics." A brief but clear-cut exposition on opsonins and vaccine therapy has