PURGATIVES also awaken the susceptibility of the body to mercurial impressions, and it is remarked by Dr. Chapman that this practice affords a resource which rarely disappoints the practitioner. This class of remedies moreover seems capable of exalting the efficacy, and indeed of accelerating the benefit to be derived from many alteratives, when administered _previous_ to the exhibition of these latter substances; the advantages of a course of Steel medicines are undoubtedly increased by such means. The febrifugous and antiseptic properties of diluted muriatic acid (see _Form. 145_.) are inconsiderable, unless its exhibition be accompanied with cathartics. I beg to refer the practitioner to some cases published by me in the _Medical and Physical Journal for December_, 1809, in further illustration of these views. Experience enables me also to state that _Diuretics_ are considerably assisted by similar means, having many instances in my case book of the failure of these agents before, and their successful operation after, the exhibition of a cathartic. Dr. Darwin observes that “_Absorptions are always increased by Inanition_,” and in support of this position refers to the frequent advantage derived from evacuations in the cure of ulcers. I have certainly seen obstinate sores in the leg cured by small and repeated bleedings. Dr. Chapman arrives at the same conclusion, although by a different train of reasoning; he states that the blood-vessels and absorbents[255] are to a certain extent “antagonising powers:” instructed by this obvious fact, we ought, says he, in the exhibition of diuretics to regulate the state of the system by interposing purgatives, or even venesection, as the state of the circulation may indicate. EMETICS also, in certain conditions of the system, would appear to render the stomach more sensible to the impression of other remedies; Dr. Eberle, of Philadelphia,[256] has remarked such an effect with respect to the administration of the Peruvian Bark.