Sect. V.--BLISTERS AND POULTICES. A blister should never be applied for any infantile disease, except when ordered by a medical man, as its injudicious use might greatly aggravate the complaint. There are also one or two precautions in reference to the mode of the application of a blister, which it is always right for a parent to attend to. From the great irritability of the skin, it should never be allowed to remain on longer than from two to four hours. At the expiration of this time, the surface will usually become red and inflamed; and, if the blister is removed, and the part dressed with fresh spermaceti ointment spread on lint, or with a soft bread and water poultice, a full blister will soon be raised: the little patient is thus saved much suffering, and a very troublesome sore prevented. A piece of tissue or silver paper, interposed between the blister and the skin, will answer the same purpose; the blister will act well, and the evils before alluded to will be prevented. After a blister has been two or three hours applied, its edge should be carefully raised, to ascertain the effect produced; and if the surface be much inflamed, more particularly if little points of vesication (watery bladders) are present, it should be removed, and the above directions attended to. Mustard poultices are invaluable in some of the diseases of infancy and childhood, and therefore frequently ordered. A mustard poultice is made by mixing two thirds of mustard flour and one third of wheaten flour with warm water or vinegar, in sufficient quantity to render the powder of the consistence of paste. It is then spread on linen from the size of a half-crown to that of the palm of the hand, according to the effect intended, and placed on the skin. How long it is to be kept on will depend upon the individual sensibility of the skin of the child; but, in general, from fifteen to twenty minutes will be found amply sufficient. The application, however, must at all times be carefully watched; for if it remain on too long, ulceration, and death of the part, might ensue; therefore, directly the skin is found tolerably red, the poultice should be removed. After its removal, the part may be exposed, or, if very painful, smeared over with fresh cream or common cerate. A bread and water poultice, although one of the commonest applications in use, is rarely well made or properly applied. It thus becomes injurious rather than useful; adding to the inflammation or irritation of the part, instead of soothing and allaying it. Nothing, however, is more simple than the mode of its preparation.