-SUK

i< the in<^ principle, is merely that it exists as a com-

ponent part in tin- greater number of acids; and that many acidsare formed by combustion, or by some equivalent process. Thetruth is, that tiie class of acids is altogether arbitrary ; formedwhen the greater number of the bodies arranged under it were un-know n, and before any precise notion of what ought to constitutethe’ characteristic marts of an acid had been thought of. Newbodies, when they were discovered, if they possessed any pro-perties analogous to the known acids, were referred without scrupleto the same class, how much soever they differed from them inother particulars. Ilenct 1 we find, under the head of acids, bo-dies which have scarcely a single property in common, except thatof combining with alkalies anil earths. From what has been stated,however, it follows, that the acids are compound bodies, and al-most all of them formed by the union of oxygen with some othersubstance: this substance is called the base, or radical. In somecases the radical has never been found in a separate state, when itis said to be unknoiin. See Act Din able base. Acids seem,from their universality, to be of the greatest use in the occonomyof the world. The air, earth, and sea, abound with them. It isobserved, that the air is most replete with acid, when the windblows from the north and east, and when the weather is serene; afact which, according to Iloffman, is confirmed by the observa-tions of tho<e who are concerned in nitre works; from whence wemay conclude, that the aerial acid is instrumental to the produc-tion of cold in the air. The analogy between acids and cold, andbetween alkalies and heat, is very remarkable. I hut and alkaliespromote the putrefaction of dead bodies; or, in other words, des-troy the cohesion of their parts: on the contrary, acids and coldpreserve them from putrefaction, by preserving the cohesion oftheir component parts. Acids are distributed into three generalclasses, according to the substances from which they are extracted;viz. Animal, Mineral, and Vegetable Acids. The vege-table acids, as the juice of limes, lemons, &c. are frequently pro-cured without the aid of art. They are of a saponaceus consis-tence, and therefore, in a variety of affections, eminently adaptedto the human constitution. In general they attenuate the fluids,remove obstructions, stimulate the appetite, promote digestion,quench thirst, and in hot seasons, counteract the putrid tendencyof the animal humours: they atford an excellent remedy in pec-toral, bilious, and inflammatory diseases, but particularly in thetrue scurvy, as likewise in all maladies of the kidneys; and arethe most effectual antidotes against the narcotic vegetable poisons.Thus, a mo.-t powerful dose oi opium may he checked in its sopo-rific effects, if a proper cpiantitv of the acid of lemons betaken,with or immediately after it. For instance, four grains of opium,or one- hundred drops of laudanum, form a large, and sometimesfatal, dose; but if one ounce of pure lemon-juice, or twice thatquantity of good vinegar, be added to every grain of opium, orto twcnU-tive drops of laudanum, such a compound will producea very different effect. Instead of stupilVing the head, and pro-} dining troublesome costiveness, it will relieve the bowels, and oc-rasion a degree of cheerfulness never attainable by the use of o-pium alone, or strong liquors; and afterwards induce a composed! and refreshing sleep. Hence (he use of acids, to persons whon o habitually obliged to take considerable doses of opiates, can-not be too strongly recommended. Few persons will doubt thegood effects of acids, when sprinkled about the floors and walls ofrooms inhabited by patients labouring under putrid disorders, es-pecially in the heat of summer. The mineral acids, however, areproductive of very different effects: when applied in a diluted stateto the human body, whether externally or internally, they gene-rally contract, and gently stimulate, the animal fibre; but, in aconcentrated form, violently stimulate, corrode, and destroy itstexture. With respect to their comparative activity, the nitricacid, or aqua fort is, is (lie most volatile; the muriatic formerlythe marine acid, or spirit of sail, is perhaps the most active anilpermanent in its effects on the human system. Hence it has latelybeen used by Dr. Reich, of (erlang, in Germany , with unex-ampled success, in the cure of the true typhus, or putrid nervousfever, after all other remedies had proved ineffectual. Thoughthe division of acids into animal, mineral, and vegetable, has beengenerally adopted, yet, a more proper distribution is to class themaccording to their radicals, for which, and a particular account oftheir properties, number, order, &c. See Chemistry.

AC ID U UK, (i. e. aqutc acidula,) mineral waters which have

a pungent acidulous taste, and sparkle upon agitation ; they containa large portion of carbonic acid,

ACIDULATED, medicines having an acid in their compo-sition.

ACIDULOUS, that is slightly acid; the same with sub-acid.

ACIDULUM, a kind of native compound salts, in which thealkaline base is supersaturated with acid; these are employed inchemical processes, and for economical purposes as acids. The(wo species already known arc, the tartareous acidulum or acidu-lous tartrile of potash; and the oxalic acidulum, or acidulous ox-alate of potash,

ACIDUM ,-Ether.eum, aluminosum, catholicum, primige -nium, sulphurcum, names for spirit of vitriol.

Acidum pinguk, an imaginary acid which some German che-mists supposed'to be contained in fire.

Acidum vitrjoli vinosum, Sec .Ether.

AC1LIUS, the sirnaine of a Roman family, which producedseveral great men.

ACIXACES, a kind of cutlass or scimetar, in use among thePersians .

ACINARIA, the marsh whortle-berrics, or vacciniapalnstria.

ACINI, in botany, small grains, or berries, growing in hun-ches, after the manner of grapes; also the stones or seeds of grapes.The berries of the alder, privet, ivy, &c. are of this kind, and socalled.

Acrxi CLAXDULosr, in anatomy, some glands so called fromtheir formation.

ACINI FORM IS tuxica, the same with the tunica uvea ofthe eve. It is also called acinostt tunica.

AC1NODEN DRON, a species of plants, called Melastoma,which see.

ACIl’ENSER, the sturgeon, a genus of fishes of the orderCartilagcnei: head is obtuse, mouth under the head, retractile,without teeth; cerri four, below the front, and before the mouth;aperture of the gills at each side; body elongated and angulateilwith many series of scaly protuberances. 'I hey inhabit tfie sea,but ascend rivers annually; the flesh is delicious; from the roois made caviar, and from the sounds and muscular parts is madeisinglass; they feed on worms, and other Ashes: the females arelarger than the males. There are live species: 1. A. sturio, orcommon sturgeon, inhabits European , Mediterranean, Red, Black,and Caspian seas. See PI. 0. lig. 2. 2. A. schypa, 3. A. ruthenus,and 4. A. stdlatus, they inhabit the Caspian sea . 5. A. httfo, in-habits the Danube, Wolga, and other Russian rivers, and also theCaspian . The skin of tins species is used for carriage-traces.

AC IS, in fabulous history, the son of Eaunus and Simetheis,was ;i beautiful shepherd of Sic ily, who being beloved by Gala-tea, Polyphemus the giant was so enraged, that he dashed out hisbrains against a rock; after which Galatea turned him into a river,which was called by his name.

Acts, a river of Sieilv, running from a very cold spring, in thewoodv and shady foot oi mount jF.tna.

ACKEN, a small town in the. duchy of Magdeburgh, situatedon the Elbe, 3 miles below Dessaw. It lias a citadel.

ACLIDKS, in Roman antiquity, a kind of missive weapon,having a thong lixed to it, by which, after easting it out of thehand, it might lie drawn back again. Servius describes the ai li-lies as full of spietike, or eminences. Each warrior seems to havebeen furnished with two.

ACME, [axjtxij, Gr.] the height of any thing; more especi-ally used to denote the height of a distemper, which is dividedinto four periods. 1. The arc lie, the beginning or tirst attack.2. Anabasis, the growth. 3. Acmi, the height. And 4. I'ar-ticlin', which is the declension of the distemper.

ACMON1A, orAGMONIA, in ancient geography, 1. a townof Phrygia Major, now in ruins, called by Cicero , civitas Ac-monensis. 2. A city of Dacia, on the Danube , rebuilt by Se-verus and called Scvcricum. It is situated 1U German miles S. E.from Temeswur.

ACNE, a small pintple , or hard tubercle on the face.

ACN1DA, Virginian Hemp, in botany, a genus of the di-cecia order, and pentandria class of plants; pertaining in the na-tural method to the Srhabrida:: Characters, Male, calyx fiveleaved; no corolla: stamina live short capillary filaments. Fe-male, calyx many leaved and deciduous; no corolla. The pis-tillum lias an ovate germen; styli five, long, reflected, and