2950. Observations On Their Use

1. Never apply a blister at the beginning of inflammation; never in its acute stage; wait till this has been subdued by other means, bleeding, &c., and then it may be used with advantage. 2. Do not apply a blister where the skin is thin and tender, the scrotum or mamma, for example, as it causes intolerable irritation; nor over a bony prominence, as the process of healing will be slow and difficult.

3. In many instances, as in acute Laryngitis, it is inadvisable to apply a blister immediately over the seat of the disease, as it sometimes aggravates the symptoms, and prevents the application of leeches and other local measures which may be necessary.

4. A buster is often more efficacious if applied to a part far removed from the seat of disease, e.g., to the heel in Sciatica and Lumbago. 5. Do not allow a blister to remain on for twelve or twenty-four hours, as is sometimes done, but at the end of eight or nine hours remove the blister, and apply soft warm poultices. Vesication soon ensues. 6. Do not apply a blister to the chest or mamma during pregnancy.

* Brit. Med. Journ., Oct. 27, 1860.

2951. To obviate the Strangury, &c., which arises from the use of Cantharides blister, one of the following plans may be resorted to: - 1. Remove the blister as soon as it causes decided pain, although the part be not vesicated, and apply simple dressings: free vesication subsequently occurs.* 2. Insert an extremely thin piece of paper between the blister and the skin. Sir B. Brodie advises the paper to be oiled previously. 3. Let the patient drink plentifully of diluents and demulcents, avoiding those of an oleaginous description.

2952. To obviate Gangrene Ulceration, &c., in infants and young children, spread the plaster on fine soft linen or calico, smear with oil, and place it on the skin until redness be produced; then remove it and apply a soft warm poultice, and in two or three hours vesication will ensue. The serum being evacuated, dress the blistered surface with Ung. Cetacei, smoothly spread upon fine cotton. This is a point of importance, many cases of sloughing having resulted from coarse dressings. Thus employed, blisters may be used with perfect safety, even in the youngest children. (Thompson. ) Another excellent and speedy method of applying blisters to young children, is to put on a mustard poultice until the skin is reddened, and immediately afterwards a blister. In an hour (it need never be continued longer) vesication will ensue. Dr. Graves § makes some practical observations on the subject of blisters on children and persons of a delicate skin, which are well worthy of attention. "In treating the Bronchitis of children and in the bronchial affections of fever, I have frequently," he observes, " directed the blister to be left unopened, and I can state, from experience, that this plan answers very well. The effused serum forms one of the best dressings for the excoriated surface of the skin, and the formation of troublesome sores is avoided. I have frequently," he continues, "had recourse to this mode of treating blistered surfaces in children, and in persons of irritable habit, in whom the cutis is extremely tender and vascular." He therefore advises, that in such persons the blisters should be left alone, particularly where they have been applied to the fore part of the chest, or to any other part exposed to pressure or friction. As soon as the blister rises, apply over it a piece of lint, smeared with spermaceti ointment, which can be renewed as occasion requires, and leave the rest to nature.

* Dr. Leaby, and Dr. Stokes, Cyc. Pract. Med., vol. i. p. 525. Lectures, Med. Times, vol. xvi. 1847. Lancet, April 18, 1846 § Clin. Lect., vol. i. p. 159.