P E E F A C E

TO THE AMERICAN EDITION.

The very great merit of Pereira's Elements of Materia Medica and Thera-peutics, liaving attracted the attention of the profession in the United States, itis believed that an important service is performed, in rendering it accessible, bythe publication of an American edition. It is by far the most comprehensivetreatise upon the subject in the English language. Replete with erudition andat the same time most satisfactory with respect to references; it is admirablysuited to the wants of the advanced Student and the practitioner; while from thedistinctness of the facts, their methodical arrangement, and the clear philosophicalexplanations connected with them, it meets the wants of the Student who is insearch of the first lessons in the science. It may, therefore, with equal benefitbe employed as a work of reference, or as an elementary text book, in whichtwo-fold character it occupies an unusual position.

More completely to adapt it to the demands of this country, such additionshave been made as are deemed to be essential. Thus, the portion devoted topharmaceutical Information, is in the original work too strictly local, as it is con-fined almost exclusively to the pecuüärities of the three British Colleges; to ob-viate this, the nomenclature of the last edition of the United States' Pharmacopoeiahas been introduced, by inserting the name of each article adopted by that Standard,in connexion with those assumed by the authorities uniformly cited by the author,or by expressing a correspondence of name with one or more of them by theSymbols (IT. S.) in union with similar Symbols used by him to indicate theanthority. The formulae of the United States Pharmacopoeia have also been setforth with the formulae of the Standards previously mentioned, and where a for-mula hns been adopted, or a medieinal preparation as.cumpd by our own work,