It should ever be the object of the practitioner to accommodate, as far as he is able, the form and flavour of his medicines to the taste and caprice of his patient, provided always that he does not compromise their efficacy, and which often appears to be nearly connected with those sensible qualities which render them disgusting and objectionable. Some medicines are more grateful to the stomach, as well as more efficacious in their operation, when exhibited in the state of effervescence. To effect this we have only to introduce an alkaline carbonate into the formula, and to direct a portion of some vegetable acid to be added just before it is swallowed. We must, however, take care that the ingredients are of a nature not likely to be decomposed by the alkali, in the first instance, or by the neutral salt, which is formed, in the second. See _Form. 27, 82, 86_. C. _By which it is_ PRESERVED _from the spontaneous decomposition to which it is liable._ It is sometimes adviseable to add an ingredient for the purpose of preventing the sudden decomposition of a medicine; thus is the _Compound Tincture of Cardamoms_ added to the _Compound Decoction of Aloes_, in order that the latter may be preserved a longer period without change. The addition of sugar will prevent ointments from becoming rancid. Vegetable infusions, that are susceptible of mouldiness, are best preserved from such deterioration by some aromatic addition. For the knowledge of this fact we are indebted to Dr. Mac Culloch, who in a very interesting paper, lately published in the Edinburgh Philosophical Journal[273] has observed, that perfumes, such as _Essential Oils_, &c. will prevent the production and growth of those minute cryptogamous vegetables, upon which the phenomenon of mouldiness depends.[274]