it may happen, as in the cauliflower excrescence, or in the oozing tumour of the labium, that such applications are too irritating; in such cases the effect of the lotion is _corrected_ by the addition of mucilage. The enfeebling influence of _Digitalis_, _Tobacco_, and some other narcotics, is successfully opposed by aromatics and stimulants. It has already been stated that several attempts have been made to correct the operation of _Opium_ by the application of mechanical and chemical resources; it would, however, appear that, for obviating its effects upon the intestinal excretions, the judicious addition of some purgative will offer the most effectual corrigent; and, according to my own experience, the _Aloetic_ preparations are to be preferred upon such an occasion, as in _Form. 11, 12, 13_. In some cases, I have found that a combination of the watery infusion of _Opium_ with some bitter, will secure the narcotic virtues without those consecutive effects upon the alimentary canal, which we are always so desirous to obviate; the _Decoctum Aloes compositum_ also furnishes upon such an occasion a very appropriate adjunct. Let us remember that one of the effects of opium is to paralyse, for a time, the muscular fibres of the intestines: now experience has taught us that the remedies above directed have a peculiar tendency to augment the peristaltic motions of the _primæ viæ_. Upon the same principle the addition of calomel will prevent the paralysing influence of this narcotic upon the biliary functions. I have known several patients who could never take opium unless in such a form of combination. In general, a formula contains but one _corrigent_; but circumstances may occur, where two different ingredients are required to obviate two very different effects, as in _Form. 16_, in which the _Nitric acid_ is introduced for the purpose of counteracting the deleterious effects of the opium upon the nervous system, while the _Aloetic_ preparation is calculated to obviate its particular tendency upon the alimentary canal. Sometimes the unpleasant or perverse operation of a medicine may be obviated by changing the form of its exhibition, the period at which it is taken, or the extent of its dose; Dr. Cullen, for instance, found that the nauseating operation of _Camboge_ might be obviated, by repeating small doses at short intervals. (89.)