There are some medicines however which require to be given to children in much larger proportioned doses than those stated above. For example, a child of three years might require half as much castor oil for a dose as an adult. Females usually require smaller doses than males, and those of sanguine temperament than the lymphatic and phlegmatic. Idiosyncracies sometimes exist in individuals rendering them peculiarly susceptible to the action of certain remedies, or causing a medicine to act on an individual in a manner wholly different from the ordinary mode. In general the susceptibility to the action of a medicine is diminished by its frequent use; some medicines are of variable strength, and all these considerations should lead to great care in prescribing; some medicines require more care than others, however, and such formula will be selected for insertion here as may be pretty generally used with safety. I believe they do not require more effort to adapt them to particular cases than ordinary patent medicines. MODE OF ADMINISTERING MEDICINE. Medicines given together should be combined with a definite purpose in regard to each article in the formula. Remedies of the same general character may be given together in order to increase their efficacy. In F. 74 there are several aromatics because a small amount of each when combined, will be more certain in their action than a large amount of one kind, and at the same time they will be less irritating. The effects of one medicine are in many cases increased by the influence of another in augmenting the natural susceptibility of the system to its action. One medicine is given with another to counteract the more disagreeable effects of the more active one. One medicine is sometimes given as a vehicle for another; perhaps to cover the disagreeable taste or odor and to render the medicine acceptable to the stomach. For example, the aromatics and ammonia in F. 74 are much more agreeable to the stomach than either of them would be separately. In the mixing of medicines care should be taken that they are neither chemically nor physiologically incompatible. When the action of an acid is desired, an alkali should not be given at the same time, as they unite to form a compound different from either. A soluble salt should not be given with another, or with an acid that would decompose it, and produce an inert compound. If medicines are given that have an apparent physiological incompatibility, it should be with a full understanding of their effects, and with reference to them. The FORM in which medicine is given must vary according to the nature of the medicine, the taste of the patient, or the condition of his stomach, as it is always desirable to have it so that it can be swallowed without difficulty.