MATERIA MEDICA is that department of the science of medicine, that treats of the nature and properties of the substances that are employed as remedies to restore health in diseased bodies.

According to this definition, it should comprehend every remedy, whether it be a simple, the production of nature; or a compound artificially prepared by the pharmacopolist; or even an affection of the mind: but the British Colleges of Physicians confine the application of the term, in their pharmacopoeias, to those remedies only which are simples, and such compounds as are articles of general commerce, or over the preparation of which they have no control. These pharmacopoeias differ also from the works of the generality of systematic writers on Materia Medica, in arranging the substances alphabetically, without any regard to their affinities as natural objects, or to their medicinal virtues. This mode, although it be not so scientific, yet is much less liable to objection than many of the other modes that have been occasionally adopted; as the best of these have been, generally, too much modified by the prevailing theoretical doctrines of the day, which, unfortunately for medical science, have hitherto had too slight a foundation on truth to secure their permanence.

The plan of the pharmacopoeias has consequently been judiciously followed by the compilers of Dispensatories: and the convenience and utility of it is so generally acknowledged, that we the more readily comply with our own opinion of its propriety in adopting it.

This part of our work, therefore, contains the lists of the materia medica of the pharmacopoeias issued by the London, the Edinburgh, and the Dublin Colleges; and subjoined to the name of each of the substances supplied by the vegetable and the animal kingdoms, a description of the plant or the animal which yields the remedy is given in the language and after the method of Natural History. The chymical characters, as far as they are known, of these matters are also stated; and the analysis of such remedies as are more immediately the objects of chymical investigation, with the medical properties and uses of all of them, are detailed; so as to afford every useful information regarding them, in a form the most convenient for practical reference.