The applying of blisters properly, against any disease, is very useful, and may be so managed as to cure various maladies. But when laid on out of season, or in some stages of a distemper, will do a great deal of hurt : therefore it is of the highest consequence to know when they are suitable, and when not.

In chronic diseases they will relieve obstinate head-achs, rheumatisms of the head, when the blood vessels of the whites of the eyes are turgid with blood attended with a moist rheum, or when the redness of them proceeds from the king's evil; as also when the eye-lids are glued together in the night by a thick humour. They are likewise good in obstinate defluxions on the eyes and ears, in a tedious running of the nose, in the tooth-ach from a ferous rheum, in sleepy disorders, in little ulcers of the head of a long standing, or when the humour of a scald head is driven inwardly. Moreover, they are useful in a palsy of the tongue, in hardness of hearing, and in a noise of the ears, from a cold cause, and when breaking out, or spots on the skin have struck in, and are to be recalled. The sciatica, or hip-gout will yield to bleeding, and laying a blister on the part affected.

In acute diseases they are likewise of great use, particularly in the small pox, when the pustules lie buried in the skin for two or three days, and when they appear like watry bladders. In the fit of an apoplexy, in low nervous fevers, in all fevers when there is a defect of vital heat, and the pulse is weak and languid; for this reason they ought to be applied at the latter end of putrid fevers, when the spirits and pulse sink, which is a sign that nature wants a spur, or when this disease brings on a phrensy, and bleeding is dangerous because the patient is very low. In this last cafe the defect may be sup-plied by applying leeches to the temples, and a blister to the head and other parts of the body. But if the pulse is funk, and the patient appears stupid or insensible, blisters and leeches must be omitted, and stimulating poultices or sinapisms must be laid to the soals of the feet. In violent inflammations of the eyes, blisters must be laid behind the ears, must lie on two or three days, and the fores must be kept running. In a quinsy, a large and strong blister must be laid to the fore part of the neck. In a pleurisy, alter the first bleeding, it must be applied upon the pained fide. In an inflammation of the lungs, after the first bleeding it must be laid to the back, and to one or both des. In a spurious peripneumony, likewise, blistering is of great service. In the inflammation of the liver, stomach, or intestines, in the iliac passion, and a fixt pain of the bowels, a large blister should be laid over the part affected; Blisters should never be applied in the beginning of common fevers, if the pulse is strong, and the disease is gaining strength; nor yet to the hectic, to women with child, to the lean, nor to those who have strong tense fibres. blisters are likewise very improper in a fit of the gravel, in the stone of the kidneys or bladder, when the patient is full of blood, without preceding evacuations, as a!so in profuse bleedings of any kind. The reason of all which may be readily conceived, when we consider that blisters act by stimulating the solids, attenuating the fluids, by re-vulsion, by bringing out the morbisic matter, and that they particularly affect the urinary passages, often causing a strangury, if not prevented in time. They should never be laid to the thighs or legs, when they are cedematous or distended with water, left they produce a gangrene. A stran-gury may be prevented by soft diluting liquors, particularly by a solution of gum arabic in water.