Some diseases, independent of all remedial measures, improve at certain seasons, and retrograde at others. We have a good example of this in scrofulous affections: in the spring this disease in every form is aggravated; during the latter part of summer and in autumn, improvements take place rapidly and uniformly; whilst during the winter it either remains stationary or retrogrades. Now, it is evident that any remedial measures in this disease must be greatly influenced by the season at which they are employed; or, in other words, by the tendency which the disease exhibits to improve or retrograde at particular periods. I believe that much of the efficacy which has been ascribed to sea-bathing in this disease is in reality due to the fact that it is usually employed at those seasons, summer and autumn, when the disease spontaneously improves. Season also influences the operation of medicines in another way; thus Dr. T. Smith observes that the Oil of Turpentine ought never to be given alone, in large doses, during the winter or in cold damp weather; because it then, like other hydrocarbons, tends to supply fuel for the evolution of animal heat, rather than to exert any therapeutic properties. Moreover, in winter, cerebral congestion may supervene, in summer intractable diarrha, if it be given in very large doses. Another example will suffice. Dr. Copland states that in the treatment of Bronchocele with Iodine, he has observed that drug, if continued during cold weather, produce pains in the limbs and joints resembling rheumatism, but that these disappeared when the weather became warm.

11. The form in which a medicine is administered influences, in many instances, its operation. When it is desired to produce a speedy effect, the liquid form is generally preferable: thus, the action of Quinine is rendered not only more speedy, but more effectual, if administered in solution than if given in substance. The same remark applies to Morphia, and to most of the alkaloids. Tannin, when intended to influence the stomach or bowels, is suitably exhibited in the form of pill; but if it be designed to enter into the circulation, or to act quickly at a distance from the stomach on some internal part, the form of solution should be employed. Digitalis, when given in the form of tincture, acts as a direct sedative on the heart and circulatory system; if given in infusion, it acts as a diuretic. Decoction is inadmissible as a form for exhibiting Ipecacuanha, Senna, and some other medicines, their active properties being dissipated by boiling. There are, however, several medicines which, from their insolubility, cannot be given in the liquid form; Calomel, and the Peroxide of Iron, for example: these are necessarily given either in the form of pill or powder. In using the pillular form, we may, in the majority of cases, advantageously add soap to the mass, as it tends materially to hasten its solution in the intestines, and thereby to quicken its operations. It also renders the action of purgatives milder and less irritating. Powders are best given in syrup, honey, treacle, &c. When they are of an insoluble character, as the Peroxide of Iron, &c, and are continued daily, for any length of time, an aperient should occasionally be given, to obviate their accumulation in the intestines.

12. The purity of the medicine employed should engage the earnest attention of the practitioner; otherwise his best efforts may prove not only unavailing, but perhaps injurious.

13. Disguising the taste of nauseous medicines is often a matter for consideration, particularly in the case of children and delicate women. Castor Oil, one of the most useful aperients in the Materia Medica, is often rendered inadmissible on account of its taste; and it is, consequently, important to discover some means by which it may be disguised, without impairing its medicinal activity. This remark applies even more strongly to Cod-Liver Oil. Strong coffee, hot milk, or lemon syrup, will answer in a degree; or the medicine may be made into an emulsion with yolk of egg, sweetened with syrup, and coloured with Tinct. Cardam. Co.; but all these plans are inferior to the simple one of chewing a piece of lemon or orange-peel, or a few cloves, or any aromatic substance, immediately previous to swallowing the medicine. I know of no way so effectual as this. The taste of Senna may be concealed by sweetening the infusion, adding milk, and drinking as ordinary tea, which, when thus prepared, it much resembles. The taste of Quinine is concealed by Tannin; Aloes, by Liquorice; and the Sulphate of Magnesia, by the compound infusion of Roses. Syrups are generally agreeable to children, and may be used for disguising unpleasant taste. In order to obviate the taste, some medicines may be given in the form of effervescing draughts, the Carbonic Acid, which is set free, tending, not a little, to enable the stomach to retain the medicine. Nauseous medicines, as Copaiba, are sometimes advantageously given in the pillular form, or in gelatinous capsules, or enveloped in wafer-paper.