Zoonomia; Or, the Laws of Organic Life, Vol. II

by Erasmus Darwin

If the itch be cured too hastily by rubbing mercurial or arsenical preparations over the whole body, or on too great a part of it, many bad symptoms are produced; as weakness of digestion, with pale bloated countenance, and tendency to dropsy. I have twice seen St. Vitus's dance occur from the use of a mercurial girdle; and once a swelled liver. I have also seen a swelled spleen and swelled legs from the external use of arsenic in the cure of the itch. And very numerous and large phlegmons commonly succeed the too hasty cure of it by other means.

There does not appear a strict analogy between the hasty cure of the itch, and the retrocession of the pustles in the secondary fever of the small-pox; because in that the absorption of the matter is evinced by the swelling of the face and hands, as the pustles recede, as explained in Class [II. 1. 3. 9]. Variola discreta. And a fever is produced by this absorption; neither of which happen, when the pustles of the itch are destroyed by mercury or arsenic.

Nor can these inconveniences, which occur on the too hasty cure of the itch, be explained by those which follow the cure of some kinds of gutta rosea, Class [II. 1. 4. 6]. as in those the eruptions on the face were an associated disease with inflammation of the liver or stomach, which they were accustomed to relieve; whereas the itch is not known to have had any previous catenation with other diseases.

In the itch there exists not only great irritation in the production of the pustles, but great sensation is caused by their acrimony afterwards; insomuch that the pain of itching, without the interrupted smarting occasioned by scratching, would be intolerable. This great excitement of the two sensorial powers of irritation and sensation is so great, when the pustles are diffused over the whole surface of the body, that a torpor succeeds the sudden ceasing of it; which affects those parts of the system, which were most catenated with the new motions of the skin, as the stomach, whence indigestion and flatulency; or which are generally most liable to fall into torpor, as the numerous glands, which form the liver. Whence the diseases consequent to the hasty cure of the itch are diseases of debility, as tumid viscera, œdematous swellings, and St. Vitus's dance, which is a debility of association. In the same manner indigestion, with green evacuations, are said to follow an injudicious application of cerussa to stop too hastily the exsudation behind the ears of children, Class [I. 1. 2. 9]. And dropsies are liable to succeed the cure of old ulcers of the legs, which have long stimulated the system.

M. M. The size of a large pea, of an ointment consisting of one part of white precipitate of mercury to six parts of hogs' lard well triturated together, to be rubbed on a part of the body every night, and washed off with soap and water next morning, till every part is cleared; with lac sulphuris twenty grains to be taken every morning inwardly. Warm saline bath, with white vitriol in it. Flowers of sulphur mixed with thick gruel, with hogs fat. With either of which the body may be smeared all over.

[7]. Psora ebriorum. Elderly people, who have been much addicted to spirituous drinks, as beer, wine, or alcohol, are liable to an eruption all over their bodies; which is attended with very afflicting itching, and which they probably propagate from one part of their bodies to another with their own nails by scratching themselves. I saw fatal effects in one such patient, by a too extensive use of a solution of lead; the eruption disappeared, he became dropsical, and died; I suppose from the too suddenly ceasing of the great stimulus caused by the eruptions over the whole skin, as in the preceding article.

M. M. The patient should gradually accustom himself to half his usual quantity of vinous potation. The warm bath, with one pound of salt to every three gallons. Mercurial ointments on small parts of the skin at a time. A grain of opium at night instead of the usual potation of wine or beer.

[8]. Herpes. Herpes consists of gregarious spreading excoriations, which are succeeded by branny scales or scabs. In this disease there appears to be a deficient absorption of the subcutaneous mucus, as well as inflammation and increased secretion of it. For the fluid not only excoriates the parts in its vicinity by its acrimony, but is very saline to the taste, as some of these patients have assured me; I believe this kind of eruption, as well as the tinea, and perhaps all other cutaneous eruption, is liable to be inoculated in other parts of the body by the finger-nails of the patients in scratching themselves.

It is liable to affect the hands, and to return at distant periods; and is probably a secondary disease, as well as the zona ignea, or shingles, described below.

M. M. Poultice the eruption with bread and milk, or raw carrots grated, for two or three whole days, to dilute or receive the discharged fluid, and abate the inflammation; then cover the parts with fresh cerate mixed with lapis calaminaris. On the parts not excoriated mercurial ointment, made of one part of white calx of mercury and six of hogs' fat. Internally, after venesection, gentle repeated cathartics. Lastly, the bark. Acid of vitriol. Bolus Armeniæ, or testacia. Antimonials. Decoction of interior bark of elm.