CLIMATE. Several observations have already been offered upon the influence of Climate in affecting the activity of our remedies.[291] With regard to its relations to _Dose_, I have only one remark to make to the English practitioner, and that by the way of caution, that he will not allow his own previous experience in hot climates, or the persuasions of other tropical practitioners to induce him to administer such doses of Mercury, in England, as may have been found salutary in India, or in other Colonies of similar temperature. The popular scheme of Gaubius for graduating the doses of medicine to different ages, which was published in several of the former editions of this work, is now omitted, as being less easy of application than the following simple formula by Dr. Young. RULE. _For children under twelve years, the doses of most Medicines must be diminished in the proportion of the Age, to the Age increased by 12._ thus at two years to ⅐—viz. 2 1 —————— = — 2 + 12 7 At 21 the full dose may be given. Every general rule however respecting the doses of medicines will have exceptions. Thus children will bear larger doses of _Calomel_ than even adults, and many medicines which do not affect adults, although exhibited in considerable quantities, prove injurious even in small doses to children.[292] In concluding this part of the subject, it is proper to impress upon the practitioner the importance of writing his prescriptions in legible characters, and of avoiding all those abbreviations which are not generally understood, or which are capable of misconstruction.[293] ON THE PARTICULAR FORMS OF REMEDIES, AND THE GENERAL PRINCIPLES UPON WHICH THEIR CONSTRUCTION AND ADMINISTRATION ARE TO BE REGULATED. _SOLID FORMS._ PULVERES. _Powders._ The form of powder is in many cases the most efficient and eligible mode in which a medicinal substance can be exhibited, more especially under the following circumstances. 1. _Simple Powders._ 1. Whenever a remedy requires the combination of all, or most of its principles, to ensure its full effects, as _Bark_, _Ipecacuan_, _Jalap_, &c. 2. Where medicinal bodies are insoluble, and indisposed to undergo those essential changes, _in transitu_, which render them operative; for it must be remembered that by minute division, every particle is presented to the stomach in a state of activity, being more immediately exposed to the solvent or decomposing powers of that organ. 3. Where the mechanical condition of the substance is such as to occasion irritation[294] of the stomach, as the _Sulphuretum Antimonii_, or in external applications to produce an improper effect upon the skin, as _Hydrargyri nitrico-oxydum_.