1. Powders (pulveres) are medicines finely comminuted by the processes of pounding, grinding, levigation, elutriation, precipitation, etc. This is a convenient form for the administration of insoluble substances, not very disagreeable to the taste. It is unsuitable for deliquescent substances, as carbonate of potassa, and for combinations consisting of ingredients which become liquid or semiliquid by chemical reaction, as is the case when acetate of lead is mixed with sulphate of zinc. Light powders, readily miscible with water, may be given diffused in that liquid, either pure, or rendered more agreeable to the taste by sugar and aroma-tics. Resinous powders, in order to be diffused, require that the water should be rendered somewhat viscid by saccharine or gummy additions. Heavy powders, as the metallic, are more conveniently exhibited in the form of electuary.

2. Electuaries (electuaria) are preparations in which the medicine is brought into the condition of a soft solid, and may be conveniently made by mixing powders, extracts, etc., with syrup, molasses, or honey. They are included among the confections in the U. S. Pharmacopoeia. Liquids may be brought into the same condition by admixture with sugar and gum. Any medicine may be exhibited in this form which is not too bulky, or too offensive to the taste. In forming powders into electuaries, the proportion of the semiliquid vehicle must vary with the nature of the article used. Thus, dry vegetable powders usually require twice their weight of syrup, gummy and resinous powders an equal weight, and the metallic a still smaller proportion. In the last case, it is well to add a small quantity of some conserve; as the tenacity of syrup or honey alone is scarcely sufficient to prevent a separation, by the subsidence of the heavier ingredients.

3. Conserves (conservse) are preparations in which fresh vegetable substances are beat up with sugar, as well for the sake of preservation, as for convenience of administration. They are included, along with electuaries, under the confections of the U. S. Pharmacopoeia. Very few medicines are exhibited in this way.

4. Pills (pilulae) are small, spherical, solid bodies, of a convenient size for swallowing. Medicines of which the dose is small, and the taste disagreeable, may be appropriately given in this form; but it is not suitable for deliquescent substances, nor, indeed, for those which are copiously efflorescent, unless previously deprived of their water of crystallisation. Hence, when carbonate of soda or sulphate of iron is given in pill, the dried salt, from which the water of crystallization has been driven off by heat, should be preferred. Care should be taken, in prescribing a substance in this form, that the adjuncts should be such as not to render it too hard, and of difficult solubility in the liquors of the stomach. As a general rule, pills recently made are preferable to the old, as being softer and more soluble; but occasionally, when the object is that the medicine should act very slowly, and consequently that it should be slowly dissolved, old and hard pills may be advantageously administered, The weight of the pill, if composed of vegetable substances, should not generally exceed three or four grains; if of metallic ingredient.-, it may be from four to eight grains. It will sometimes be useful, when the ingredients of the pill are very offensive to the smell or taste, to give it a coating of some material, either tasteless or not disagreeable, which may be readily dissolved in the stomach. Gelatin and sugar answer this purpose very well, and are easily applied. Gold leaf, formerly employed, is objectionable from its insolubility.

Boluses are preparations similar to pills, but larger, and may be preferably used where the dose is large, and the patient can swallow them without-difficulty. Their size is limited only by the patient's capacity of deglutition.

5. Lozenges, or Troches (trochisci), are solid masses of various shape and size, which may be conveniently held in the mouth, and there allowed slowly to dissolve. They are adapted for the administration of medicines of agreeable taste, or of which the taste, if disagreeable, can be qualified or covered by pleasant additions. They should be made with materials which, without being wholly insoluble, are dissolved slowly by the saliva. Demulcent medicines are often administered in this form; and it is convenient in all cases, in which the object is to sustain a slight impression steadily on the interior of the mouth and fauces. Sir J. Y. Simpson, of Edinburgh, informed me that he was much in the habit of administering certain medicines, especially to children, in the form of biscuit, the powder being incorporated with the dough, and then baked with it. Of course, this method of administration is applicable only to substances not injured by heat.

6. Cataplasms, or Poultices (calaplasmata), are intended only for external use. They should be soft and moist, somewhat tenacious, and of such a consistence as to accommodate themselves accurately to the part to which they are applied, without being disposed to spread, or to adhere firmly to the skin. They may be employed solely in reference to the sedative influence of the water they contain, or to protect the diseased surface from the air, or to produce the peculiar impression of a medicine either on the surface, or, through the medium of absorption, upon the system.

7. Ointments (unguenla), Cerates (cerata), and Plasters {em-plastra) are preparations also intended exclusively for external use. As the terms will be frequently used, the student should have a precise idea of their meaning at the outset. Ointments are soft solids, always containing fatty or oily matter, and capable of being applied by gentle rubbing, or, to use an appropriate phrase, by inunction. Cerates are of a firmer consistence, generally contain wax (cera), from which they derive their name, and are capable of being spread by means of a spatula, at common temperatures, upon suitable dressings, in which state they are usually applied. Plasters differ from cerates in possessing a still firmer consistence, requiring heat in order that they may be spread, and, though quite firm and brittle at common temperatures, becoming softish, tenacious, and adhesive at the temperature of the skin. Either of these preparations may be employed exclusively for local effect, or with a view to act upon the system. For the latter purpose, the ointments, are preferable when the cuticle remains; as, by the friction with which their application is often accompanied, they may be forced between the epidermic scales, and thus brought more completely within reach of absorption.

8. Extracts (extracta) are rather modes of pharmaceutical preparation, than forms for administration. They consist of the active ingredients of complex medicinal substances, extracted by water, alcohol, or acetic acid, or by expressing the juice of plants, and then evaporating to the solid consistence. Some of them are so dry that they may be readily reduced to powder, and given in this state. All of them may be administered in the form of officinal mixture. But the most common method of exhibition is in the shape of pill, to which they are often very readily brought, in consequence of their soft, somewhat cohesive consistence.