of the powder of Staphysagria, which in Greek fignifies wild vine, and is esteemed fo fpecific in the prefent cafe, that it has been called Herba pedicularis. Its dofe is half an ounce, the powder of the root of white hellebor to two drams, boil them in a fufficient quantity of Narbon-honey, fresh, lard, or laurel-oil; make an ointment, which is to be used like the former: but we are feldom obliged to have recourse to this method.

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3. The fimple powders are more in ufe, especially if there be a Crufta lactea, Tinea, or Scabies. For inftance, the powder of the feed of Staphysagria. If this is ineffectual alone, add a fourth part of the powder of white hellebor, or of aloes; for these are the most specific remedies in this disease. Where the scab and matter in the above diforders are more abundant, apply chiefly the powder to that part.

4. Perfumes to the part affected are employed with fuccefs. They are made of the powder of the feed of Staves-acre, which is thrown on the coals, and the fume received on the affected part alone, if poffible, avoiding

avoiding with care its influence on the nofe, eyes, &c. If it be neceffary to render this powder ftronger, add white hellebor, or aloes.

After the cure of the diforder, we may make the two following reflections thereon. I. Although mercury is the only specific and most powerful remedy that can be employed in the Phthiriafis, either in lotions, unctions, powders, or fumigations; yet we may as juftly apprehend its bad confequences here, being immediately applied to the head, as we do in the treatment of venereal diseases; wherefore, if it be abfolutely requifite, the moft fimple preparation I know of, is its Amalgama with gold or filver, wherewith the goldfmiths commonly rub these metals to polish them the better. The linen cloth with which this is rubbed to the faid metals, may be alfo applied to the child's head, and will be very useful; its efficacy is owing to the mercury which it contains.

II. If the vermin still refift the power of all these remedies, and the patient has at the fame time a crufta lactea, tinea, or fcabies of the head, it is in vain to attempt

their destruction any farther, till these diforders are cured; then the vermin will yield. more the easily to proper remedies.

CHA P. III.

Of the IMPETIGO.

THIS diforder is called Mentagra in greek; Lichen, Impetigo, Ignis volaticus, or filveftris in latin. Some call all kinds of Impetigo's by the name lichen; but more judicious authors apply it to the present fort of Impetigo, to which is also juftly applied the word Impetigo in exclufion to all the reft; and fome of its fpecies they call Papula, adding benique or maligna, according to their quality. As to the name Mentagra, it belongs rather to a more violent diforder, of whofe qualities the prefent does not participate. It is called ignis volaticus or filveftris, as fome diforders are ftiled ignis facer and Perficus; either because of the heat that attends it, or because it fuddenly appears and difappears, in which fenfe the name is very applicable to it. Some attribute these changes of the diforder to the variations of the moon:

but

but we have refuted this opinion, fpeaking of another diforder before. It is mostly obfervable in children from fix months old to the end of the fourth Year. In these it be-. gins to appear by fmall red veficles, or. papula, which afterwards degenerate into phlyctenoides, having a whitish spot in the. center of each papula. These are like a miliary eruption, appearing commonly on the chin alone, and thereabout. At length these tumours emit a vifcid matter, which is dried, and turned to a scab on their furface. This frequently falls off, and the disorder quite difappears, without leaving the smallest veftigia or cicatrice, which argues that the cutis is not affected, but the cuticula alone. Its origin, progress, and declension are very like to thofe of the Crufta lactea, from which it seems at first to differ only in its seat, and by its obftinacy.

The feat of the Impetigo is in the sebaceous glands, or in the cellula of the corpus mucofum, but more especially in the former, and not profoundly feated in the fkin, as fome think; otherwise it would give occafion to proportional cicatrices; whilft, on the contrary, no fuch ever fucceed

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ceed the disorder. The febaceous humour, through its fpiffitude, fettles in these organs, obftructs them, and at length, by the acrimony of the matter, they are perforated, and the included humour tranfudes. But why should the Impetigo more frequently appear on the chin, than any other part of the face, head, or body, fince the sebaceous glands are very numerous in all thofe places? I know no other answer to this difficulty, but the two following, viz. 1. That as this evil most commonly affects newly-weaned children, the habit they then contract of conveying feveral fordid dirty things to their mouth, to amufe their fancies while they think of fucking, difpofes very much the chin to this diforder. 2. As infants are very fubject to drivel vaft quantities of faliva, those especially who are troubled with dentition, they are for this reafon the more difpofed to an Impetigo on the chin; because the infpiffated faliva, like a plaister, ftops the pores of the febaceous glands; whence they are glutted and obftructed with their proper humours, which corrode them at length, and procure themselves a paffage,

SYMPTOMS