Astringents are those medicinal substances which act upon the simple elementary fibres, by contracting them, and increasing the force of cohesion, so as to re-lieve that degree of which depends on their deficient powers of contraction. This want of cohesion, being supposed to: either from an aqueous consistence, or a deficiency of animal jelly, in the interstices of the fibres, it appears to follow, that substances affording much nourishment, and containing matter for the supply and condensation of that medium between the solids and fluids, in the, greatest proport;on, are likewise the most effectual astringents. Indeed, daily experience speaks in favour of this apparently well-founded conjecture. But as mankind seem, from the earliest ages, to have been dissatisfied with those simple and congenial substances, which beneficent Nature granted them, even in the most i hospitable regions; they have, by gradual steps, forsaken her path, and re-sorted to artificial means, which chance or credulity induced them to procure from distant climates. Thus strangely has man, in all civilized countries, suffered himself to be, misled by prejudic;; and, instead of invstigating the true nature and uses of things at home, he went in quest of foreign auxiliaries, and frequently sacrificed the very life he was anxious to preserve.

In order to ascertain, with precision, when astringent remedies may be employed with safety and advantage, we shall reduce the subject to distinct propositions.

I. The cases in which it will become necessary to have recourse to astringents, are :

1. A general, and local, debility, or relaxation of the fibres : the former is relieved by the internal and external use of tonics ; but the latter, chiefly by local applications, such as cold fomentations.

2. In a preternatural, and particularly a putrid disposition of t!.c fluids,

3. S. In injuries of the vessels.

On the contrary,

II. The following circumstances and conditions prohibit the use of astringents :

1. A general rigidity of the frame, and tension of the solid parts.

2. Unusual heat of the body, unless it proceed from a general or partial debility, or a dissolution of the fluids.

3. Salutary and critical discharges, which take place by a spontaneous effort of nature..

4. The existence of some morbid matter in the body, the evacuation of which might thus be checked and prevented.—Hence it is attended with peculiar disadvantage and danger, to apply such remedies externally, as for instance, cold baths in rheumatic, gouty, erysipelatous and other affections, in which there is a natural disposition for expelling the morbific matter (or at least its residuum) by the pores of the skin. Thus the eating of astringent food would be pernicious, if the first passages be obstructed, or the person liable to habitual costiveness; though this rifle is not without its exception, especially in putrid, bilious fevers, where astringents must frequently be combined with purgatives, to answer both intentions, and to support the sinking powers, without the loss of that time, which complete evacuation would neces-sarily require.

In order to enumerate those astringent remedies which, partly by our own experience, and partly by that of others, have been found the most efficacious, either externally or internally, Ave shall here alphabetically arrange them, and treat of their individual properties and effects, under .their respective heads, viz. Alum; Bark, the AN-gustura, Horse Chesnut, Peruvian and White Willow; Bile of Animals ; Buck-bean or Marsh Trefoil; Centaury the Lesser; AvenS-root; Gentian; Water-Hemlock; Iron; Milfoil; Mineral Acids and Waters; Oak; Pichurim-beans; and simple Water.