The names of vegetables have also been accommodated to the latest systems of bo tany, so that they may not hereafter con tradict the terms of that science, or de ceive the practicioner in his references thereto. Many names of medicinal plants were in the earlier periods of botany drawn from those of families to which modern system does not admit them to belong*, but have been retained in phar macy, though wholly at variance with the improved state of science. The Commit tee trust they have been able to remedy this inconvenience, without very frequent violence to the names commonly employ ed, They have thought it most conveni ent, and fully sufficient, to express each article in general by a single and have retained the former one wherever it accorded either with the generic or specific name of Linnxus, both of which, however, it has been necessary to em ploy, for the purpose of distinguishing between them, when more than one species is taken from the same genust. There being some vegetable substances, the names of which are in a manner inde pendent of botanical nomenclatures, no alteration with respect to these seemed necessary, for in fact they are not at va riance with modern science. Intending, moreover, that the pharmaceutic name shall, where a part of a plant is used, re fer to that part only, they have transferred the term expressive of such part from the first column of the catalogue, in which it formerly stood, to the second.
2. Weights and Measures. From the great uncertainty of the customary mode of dividing by drops any quantities of liquids of less bulk than a drachm, and the increase of that uncertainty by the late introduction, into some shops, of measures applying to liquids of different densities, the bulk of a drop of water as a standard, the Committee have been led to consider the subject more particularly, and to adopt means for the removal of this uncertainty in the exhibition of many active remedies for the future. They have, for this purpose, adopted the graduated measure of the late Mr: Lane; which is founded upon an accurate divi sion of the exchequer wine gallon down to the one-sixtieth part of a drachm, and which is equivalent to a drop of water. Of course it is their intention, that the common method of dropping liquids of * Cieuta, Ilelleborics taus. f .aconitunz. Cascarala.
Rosa Calico. Rosa caning.
§ Arabieum gumnd.
different densities should be disused, and • the measure received into the shops of apothecaries, a point upon which it will be necessary to place especial stress, in order that prescriptions may be accurate ly prepared. As the same Latin term has been employed to express the pint mea sure and the pound weight, they have extended the same resemblance to in ferior measures, and have the more rea dily substituted Branum for gutta, because the latter term implies that peculiar mode of division which they wish to de precate.
3. Arrangement. On this head it is only necessary to observe, that the chapters have been arranged in what appeared to be a more natural and convenient order of the substances concerned than the former one.
4. Processes. Considerable alteration has been made in various processes, by which it is hoped they will be found more accommodated to general use. Expense in preparation ought not to be balanced against correctness and uniformity, and it is to be lamented that the profits and competition of trade should have induced a very extensive disposition to deviate from the directions of the Pharmacopoeia. To this point, therefore, the Committee have looked with much attention, and, as far as they have thought themselves justified they have endeavoured to make such deviation less an object to the ope rating chemist than heretofore ; for this purpose they have not looked in their formulae to that accuracy which would be necessary for chemical tests, but rather to the uniformity of the preparation, and its use as a medicine. The directions for manipulation are given generally, be cause they admit of some variety in their application in many instances, according to the scale on which they are prepared, and other circumstances; the Committee trust, however, that, if their directions be followed, the results will be in the same proportion uniform and correct, and that the well educated apothecary will have no difficulty in understanding and apply ing them. Under this head, it is particu larly incumbent upon the Committee to acknowledge the great advantage they have derived from the liberal communica tions of the Society of Apothecaries, with respect to the practice of their ex tensive concern, and also from many ii.cli viduals engaged in chemical preparations upon a large scale.
5. Omission of former Articles, and In troduction of new ones. In the rejection of many substances of trifling importance or efficacy, of others which have ap peared rather to belong to extemporane ous prescription, and of certain forms of medicine which have become obsolete in general practice, and also in the intro duction of any new articles, the Com mittee have exercised their own judg ment freely, and they trust with sufficient caution. They hope the College at large will approve of their having neglected to insert many substances which individual practitioners have recommended and employed, where such have not received the sanction of more general experience. They conceive further, that a strict ex amination of its powers ought to precede the introduction of any article into the Pharmacopoeia, and that the late appoint ment of a Committee of the College for this express purpose will hereafter ap preciate the value of such recommenda tions by surer tests than those which have heretofore been deemed sufficient.