The choice of these medicines, as adapted to parti-cular constitutions, furnishes little subject of rem In general the more active drastics should be avoid the weaker habits; and we have suspected that some of the poisonous anthelmintics are not exhibited without danger. The muriat of barytes and the male fern root have, we think, been sometimes injurious. The fetid hellebore, though apparently the most suspicious medicine, from frequent trials we can pronounce free from any effects inimical to the general health.

The classes of the materia medica are not so numerous as to require what is usually styled a methodus; and, if any thing were sacrificed to the parade of system by this means, it would be improperly adopted. Whatever may be its merits, it has no disadvantages, for the arrangement is exactly such as if the orders were natural and independent; and the clavis limits the intention of the group with peculiar accuracy. The evacu-ants most nearly related follow each other; and as no evacuation can take place without the excitement of the vessels as muscular organs, so in the following class, stimulantia, where the nervous system is more generally affected, a general action of the vessels of the whole system usually accompanies. Of the synonyms of Stimulantia the two first, should such medicines exist, act more peculiarly on the nervous system: the two last are topical remedies. The distinction between general and topical medicines usually admitted is, at best, useless, if not injurious; for the most active internal medicines, are often powerful topics.

The next division is also connected with some action on the sanguiferous system, which disappears in the second class, the antispasmodics. Resolvents are truly refrigerants, for discutients occur in a subsequent part. The medicines which increase tone are included under tonica, and the astringents are referred to those medicines which act on the simple solid. Some certainly act on both, and astringents, as already explained, (sec Astringentia,) sometimes appear to be tonics. The medicines which diminish tone, diminish also sensibility and excitability; and we have added as synonyms anodyna and inirritantia; those which possess an opposite quality are commonly associated in idea with stimulants.

We have admitted, with limitation and reluctance, any action of medicines on the fluids, adopting the axiom of the nervous pathologists, that the constitution forms its own fluids. Yet some complaisance is due to many excellent physicians of the Boerhaavian school, and it is at least necessary to point out the medicines which have been employed with these views. The third of the classes of the first division, the alterantia, is vague; yet the action of remedies in scurvy, in what are styled scorbutic eruptions, in lepra, and some other cases, must be collected into one group, and it is not easy to find a more proper place. In the second division we clearly perceive the action of demulcents on the throat, the stomach and alimentary canal, the urinary organs, and perhaps the bronchial glands. The antacids and antalkalines are at least useful in the stomach, and some medicines undoubtedly act, chemically, as antiseptics.

The medicines which act on the simple solids afford few subjects of remark. If relaxants are any thing more than emollients, they bear the same reference to the sedantia that the astringents do to the tonics; at least they seem to act through the medium of the simple solid. For these and the other reasons assigned, the astringents are referred to this place. The last general division contain classes independent in their operation on each other. Lithontriptics may be only antacids, but they arc said, with confidence, to dissolve the calculus. Anthelmintics may be only drastic purgatives, but some at least kill worms. The observations on the subdivisions of the catalogue must be deferred till that is concluded.

It is a common objection to any arrangement, that some medicines possess very different powers, and that their proper places are not easily ascertained. Instances of this kind occur in mercury and steel. Repetition, however, is unavoidable; and those who seek for the medicine appropriated to any disease in such catalogues, must find them in each list. The more general author on the materia medica, will treat of them under that head where their powers are most conspicuous; and the medicine will again recur, where, from its preparation, or exhibition, peculiar properties are discovered in it. The catalogue, which we shall add, will differ from former ones by the subdivision into groups, which may be styled orders, an attempt first made by Dr. Duncan in his Therapeutics. The plan we have followed is adapted to the therapeutical ideas offered under the different articles; and we consider this mode of arrangement as peculiarly useful at least to the student, since it offers at almost one view a more distinct idea of the powers and properties of each medicine than is obtained in the best systems. The catalogue itself can possess no other very peculiar advantages; yet we cannot conclude this part of the subject without acknowledging our obligations to the very excellent syllabus of Dr. George Pearson, who lectures on the materia medica with distinguished, and if we can judge from this little work, with the most merited reputation.

In our general observations on the materia medica, we mentioned the plan of some authors, and particularly of Tessari, of distinguishing the degree of power by slight marks at the end. This idea we have occasionally pursued; and while we have followed, without any very nice discrimination, the conduct of our predecessors in the medicines inserted under each class, when their powers are considerable we have added a note of admiration (!); when dangerous two (!!); when trifling, a semicolon (;); when doubtful, a note of interrogation (?); when the medicine has been introduced by fancy, folly, superstition or prejudice, a colon (:). These marks are only added to a few, and for the Linnaean appellations and synonyms the reader is referred to the separate articles.