Many authors on this subject have followed a more arbitrary arrangement, though in part botanical. Thus, Simon Paulli has divided his plants as they flourish in either of the four seasons; Vogel, according as the leaves, bark, wood, or roots are employed, again subdivided as frequently or seldom employed, or as obsolete, arranging them afterwards alphabetically. The subject is thus broken into so many detached parts, that from the laboured order the greatest confusion arises. Vogel is also a most laborious collector, with little discrimination; and though a judicious practitioner, seems in this work to have forgotten himself, and to have become a compiler only. It is, however, a manual little inferior in extent of compilation, though of comparatively little bulk, to that of Murray. Another collector who follows, in part, a botanical arrangement, hut who does not display a superior discrimination, is Dr. Alston. His chief value arises from his copious compilations from the Greek and Roman authors; but his materials are so inartificially and unpleasingly compacted, that we suspect that he has been seldom read.

Herman, in his cynosura of the materia medica, has united the botanical and chemical authors. He arranges his vegetable remedies from the parts employed, and subdivides them according to their chemical analysis. His work is little known in this country, and as a compilation from almost forgotten German authors deservedly neglected. Geoffroy, who follows a botanical arrangement, has been also peculiarly attentive to chemical analysis; and his Materia Medica is equalled by few works on the subject in extent of information or judicious discrimination. It is unfortunately little known, though meriting from the student minute attention;, and there are few veterans in practice who might not consult it with advantage. The Supplement, containing the account of animals by Nobleville and his coadjutors, is of very inferior merit. Neumann, in his chemical works, gives us some very judicious and minute analysis of vegetable remedies; but the system of materia medica which rests chiefly as the foundation of its arrangement on the chemical contents of medicines, is that of Cartheuser, which, on this account, merits particular regard, and is, in some other views, a valuable and judicious work.

If these systems are arbitrary in their arrangement, and, with the exception of the apparatus medicaminum giving little assistance to the student, and scarcely illustrating the use of any medicine, by the observations that may have been offered on the preceding or following article, still less advantageous must be the alphabetical order which Lewis has followed in a most admirable work, and Dr. Rutty, in a very inferior one, on the materia medica; an arrangement, if it can be styled one, which Vogel, Geoffroy, and Herman, have in a great degree adopted. The therapeutical writers on the materia medica have followed a very different path. Considering medicines as producing certain specific changes in the body, those which produce given changes are arranged under the different and appropriate heads. We thus find not only the principles on which they act, but are able, with very little inconvenience, to compare in given circumstances the advantages and disadvantages of each, or when disappointed in the effects of one, to supply its place with another. In this way also the individuals of each class form one separate distinct subject, scarcely, if at all, broken by a consideration of the different qualities of each. In the arbitrary alphabetical arrangement, which, from the nature of this work we are compelled to adopt, we can scarcely avail ourselves of the advantages just stated. We have endeavoured, however, to combine this plan by enlarging the therapeutical articles, and interweaving, in these, the foundation of our choice of individuals, in different circumstances.

It will be obvious, that in pursuing a plan of this kind, authors must differ according to their different objects. Thus Spielman, who connects the chemical and therapeutical sects, scarcely employs indications but as the titles of his chapters; while Dr. Cullex, diffuse on the therapeia, is short and often unsatisfactory in the history of many individuals. In short, this latter work, though vast, bold and comprehensive in its design, is, however, as it has been styled by an able critic, rather the philosophy of the materia medica than a detail of the nature and properties of medicines. Crantz' work is short and unsatisfactory in a therapeutical view, though judicious and able in the remarks on different medicines; while Junker, and De Gorter, offer little but a catalogue of medicines arranged according to indications. The latter, though published as that of David, was really the work of his father, John De Gorier, one of the most judicious and intelligent commentators on the aphorisms of Hippocrates. The choice of the plans of teaching the materia medica must lie between the arrangement of medicines according to their natural orders, or according to their therapeutical qualities. The botanical affinities in the Linnaean orders are not, however, so strictly medical as to render this plan very eligible, and though the arrangement is improved by Murray, it is far from being sufficiently accurate for this purpose. The natural orders of Jussieu, as more numerous, are more natural in a botanical view, but are consequently- lessusefully therapeutical. The therapeutical plan is, therefore, undoubtedly preferable, and, with it. the former may be more intimately united than by Dr. Cullen, for he has not introduced all the natural orders of Linnaeus, though he has grouped some vegetables, in orders strictly natural, not found in the fragments. The orders are not so numerous as to require what Linnaeus calls a method, or a clavis, to connect them; yet their arrangement is by no means to be neglected, as the therapeutical observations necessary to introduce each are intimately connected. Dr. Lewis has proposed an arrangement of the materia medica into eleven natural orders, which are not formed exclusively from the properties or the effects. These are acids, absorbent earths, insoluble earths, glutens, oils, astringents, sweets, acrids, aromatics, bitters, and emetics, including cathartics. These orders certainly afford no eligible system of arrangement. Some minuter groups retained in the foreign pharmacopoeia, as the four cold seeds, etc. we shall notice under Pharmacia.

In Dr. Cullen's system the materia medica is divided into nutrients and medicines: nutrients are food and drink, with which condiments are joined.

Medicines either act I. on the solids, or II. fluids. The first act either on the simple or the vital solid. Medicines which act on the simple solid are astringen-tia, tonica, emollientia, and erodentia. Those which act on the vital solid are stimulantia, sedativa, including narcotica, refrigerantia, and antispasmodica.

Those which act on the fluids are such as either produce a change, or occasion some evacuation. The changes respect the fluidity, comprising attenuantia and inspissantia, or the mixture: when they correct general acrimony, they are styled demulcentia; when particular acrimony, antacida, antalkalina, and antiseptica. The medicines which occasion evacuations are errhina,sia/a-goga, excpectorantia, emetica, cathartica, diuretica, dia-flhoretica, and menagoga.

In this arrangement Dr. Cullen has forsaken his own system of pathology, since the fluids, in his opinion, are not affected, without previously influencing the moving powers. Some other critical remarks might be added, were this the place for such disquisitions. To connect this part of the work with what has preceded, and will follow, we shall add what appears to us a more convenient arrangement, and subjoin a list of the materia medica adapted to it, adding the pharmaceutical or Linnaean names, while the more particular refc-ences may be found under each article.

It has been usual in these circumstances, with Spiel-man and Cullen, to premise the nutrientia; but as this would only extend the clavis, and we have already treated of it at some length under Aliment, q. v. we shall now omit this class, which consists only of food,