The earliest therapeutical authors were the natural historians; for to their descriptions of plants were usually added their medical virtues. The herbals, as they may be called, from the time of Theophrastus and Dioscorides to Gerarde, etc. are full of extravagant commendations of the most inert vegetables. The latter authors were indeed compilers only; and, if they added

6 B 2 to the bulk of their volumes, were little anxious about their value. They are, in general, careful to tell us in what degree a medicine is hot or cold, to what temperament it is best adapted: but to distinguish the diseases, or the periods of any disease in which a given plant would be most salutary, was often beyond their powers.

When botany assumed a more scientific aspect, and distinction as well as description was its object, our knowledge of the materia medica was greatly assisted. The herbalists had accumulated their commendations with little discrimination; but in the materia medica of Linnaeus we find more accuracy. He first published that of the vegetable kingdom, and afterwards in the Amoenitates Academicae those of the animal and mineral. In each he followed his own system. These treatises were republished by Schreber at Vienna, in 1773, with additions from the Amoenitates and the later works of the northern naturalist. In this volume we are told whether a medicine is common, rare, or useless; and, in enumerating the qualities, which arc those of the greatest importance, the author points out often, by distinguishing marks, how far the boasted powers may be depended on. Tessari, in his republications of Linnaeus's system at Venice under the title of Materia Medica Con-tracta, has carried this plan farther; and in a Ms. which was some years since intended for publication, it is still farther extended and more complete. Bergius, an author of the Linnaean school, has described plants according to his master's system, and, in the most precise and pointed language, conveys very accurate ideas of the sensible qualities of every vegetable remedy. Of the qualities he only mentions the most important; and the practical observations, almost exclusively his own, are few, though important. He apoligizes for not copying former authors by observing, "that those who have examined them will soon discover that so many fictions are interspersed with what is true, that they cannot be easily separated. Many writers on the materia medica, he adds,"have injured this science by trifling fictions and conjectures; by inventing qualities dictated by their prejudices, which they have obtruded on nature. Some have compiled from former authors, inserting their own opinions and their own observations. Many, with too much credulity, have adopted and transcribed the assertions of their predecessors, though of doubtful authority and sometimes ridiculous, so that, in more recent authors, we find the old remnants repeatedly hashed; blunders again and again copied." We add the words of Bergius partly as an apology for ourselves, since from the pages of Motherby we have been obliged to expunge qualities of medicines far more numerous than those which the experience of others, or our own, has justified us in retaining. The pharmaceutical and miscellaneous remarks of Bergius are highly valuable; and we regret that the animal and mineral kingdom had not equally shared his attention.

Haller, in his description of the plants of Switzerland, has followed, in the arrangement, his own botanical system. As usual, he has annexed to each plant its medical virtues; and this portion of the work has been republished by Vicat in two small volumes. Haller seldom indeed speaks from himself; for he was not a practical physician, and his compilation is not very discriminated. The best part of his work relates to the domestic medicine of the Swiss mountaineer:. Di Woodville's Medical Botany is of this class; but in ' his three volumes he only considers the vegetables included in the lists of the London and Edinburgh colleges. In the fourth, some of the plants used in medicine, not included in these catalogues, arc figured and described. The substance of this work is chiefly taken from the materia medica of Lewis and Cullen; but the plates, which are indeed elegant and accurate; are equally beautiful, and far more numerous in the large and expensive folio of Plenck. Ray, in his history of plants, adds their medical virtues; but Ray, like Haller, was no practitioner; and the greatest abilities, the soundest judgment, will not teach that nice medical discrimination, without which compilations are useless. Yet Ray's collections are so extensive, that he merits all the attention, which is not inconsiderable, that he has received. Some other authors have treated of the materia medica as general botanists. The pharmacologia of our own Dale is obsolete, yet it displays judgment and discrimination; for he has avoided the common error of his predecessors, that of collecting every idle observation from the works of his predecessors. Simon Paulli's Quadripartitum, Botanicum, connected, however, but slightly with the botanists, is deservedly neglected; and Zorn's Botanologia Medica, in the German language, scarcely merits more attention.

It is not from forgetfulness that we have omitted noticing Murray's Apparatus Medicaminum, in six volumes of unequal bulk. We have separated this work from the rest, because it affords the first example of arranging vegetable medicines from their natural orders. We have already spoken of his merit in this respect; and must now add, that he has collected with great care what the best practitioners who preceded him had taught, and has probably left little for his successors but the labour of discrimination. This part of the task he has greatly neglected; and his work is, on this account, by far less valuable than it might have been. His collection, however, is by no means like that of Vogel, indiscriminate. Gmelin has published the materia medica of the mineral kingdom as a Supplement to Murray's Apparatus, but with still less discrimination, and with very few marks of a correct judgment.