Page:Willich, A. F. M. - The Domestic Encyclopædia (Vol. 1, 1802).djvu/319

289&#93; BLI ehest, to the breast and between the shoulders 5 in apopledtic tits, to the temples, &c. In paralytic diseases, it is of the utmost consequence to place, the blister in that direction which cor- responds with the situation of the nerves in the part affected; and, in rheumatic disorders, such places should be preferred, as contain nerves connected with the painful part, immediately under the skin. Thus, in the most acute lumbago, or sciatica, it would be of little use to blister the hip or thigh, where the nerves are situated deep in the muscles 5 but by applying a vesi- catory to the sole of the foot on die same side, we may promise almost certain relief. In all inflammatory, and especi- ally in nervous affections, attended with a small, feeble pulse, and where die powers of Nature are ra- pidly declining, die use of blisters is very extensive. Their operation is in a great measure mechanical; as die first action is that of stimulating the vessels of the skin, inducing die blood to flow from the part most wheeled by inflammation, to the surface; thus exhausting die prin- ciple of irritability, and collecting die serum, or watery part of die vital fluid, under the cuticle. We shall farther observe, that in acute and dangerous diseases, where it is often necessary to re- peat the application of blisters, the new one should never be delayed till die former is completely healed. But, with respect to the time they are to be left on the skin, much depends on die degree of irritabi- lity in the patient, as well as the relative strength of the plaster. Some constitutions, of an irritable fibre, experience its effects in less ho, in.— vol. 1. BLI [2S9 than half an hour, while in odiers it may remain four, six, or eight hoars) without raising the skin. In opening a blister, it is not necessary to cut away the epidermis, or scarf skin, and to cause unnecessary pain and irritation ; as a single lon- gitudinal incision is sufficient to give vent to the collected humour. Blisters sometimes operate on die urinary canal, and produce a painful strangury, or difficulty of making urine: this effect maybe remedied by die internal use of camphor, assisted by diluent and agglutinating emulsions, such as strong decoctions of barley, lint- seed, solutions of gum arabic, &c. ; and to prevent such accidents, the blister itself may be mixed with camphor. If, on the other hand, they will not draw, the skin ought to be previously nibbed with strong vinegar: or, if their action be too violent, a little of die extract of henbane may be added to die com- position. Caution. "We think it our duty to warn the reader against the use of blisters, in which die Spanish flij is the principal ingredient. In pledioric persons, or diose of a full habit, they increase the circulation of the blood ; and ought to be ap- plied only after the necessary eva- cuations have been strictly attended to. In diseases of aputrid tendency, such as low fevers, and bilious di- arrhoeas, they are pernicious, be- cause they stimulate and spread the co.itagion over die whole frame. Lastly, when die humours are ob- viously in a state of dissolution, which is evident from the sallow and lifeless complexion of Cachectic persons, blisters are not unfre- quently productive of incurable mortification. These fatal effects, howCT er, seldom or never take place U from