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fqueez/d, and (o emit a fluid Matter, which lubricates the FafTages ; and which mixing with the feculent Matter of the Inteitines, (which is render'd fluid by the fame a&iveand ftimulating Quality of the Purgative Medicine) renders it more fluid ; by which, and by the uncommon Contractions of the Inteftines, it paffes more eafily and plentifully into the Intefiinzira re&um, and is thence ejected by Stool.
Thus do gentle Purges a£l 3 and only cleanfe the In- terlines 5 few of their Particles entering in by the Ladreal Veins fo as to affect the Blood. But in violent Pur- gatives, the ftimulating Particles are mixed with the Blood, and produce there, many times, very great Effecls, by oc- cafioning unnatural Fermentations, by feparating the natural Cohefions of the Fluids of the Body 5 and do alfo, by velli- catingthe fpiral Fibres of the Veins and Arteries, bring thofe into more forcible Contractions, and thereby accele- rate the Motion of the Blood All which may havefome-
times a good, fometimes a bad EtTecl.
As to the Eftecfs of Purgatives, on animal Bodies, Dr. putney adds, that every irritation of the Inteftines, either quickens the periftaltic Motion in its natural Direction, or occaiions fome little Inverfions of it — Now, in both Cafes, any Matters that but flightly adhere to the Coats, or inner Membranes, will be loofen'd, and ihook off, and carried forward with the other Contents 5 and they will alfo be more agitated, and thus render'd more fluid.
Hence is manifeft, how n purging Medicine haft-ens and increafesthe Difcharges by Stool 5 but the fame manner of Operation alfo carries its Effects much farther, in propor- tion to the Force of the Stimulus : For where it is oreat all the Appendices of the Bowels, and even all the Vifcera in the Abdomen, will, by a confent of parts, be pull'd or twitch'd, fo as to affeel: their refpeftive Juices in the fame manner, as the Inteftines themfelves do their Contents.— The Confequence of which mutt be, that a great deal will be drained back into the Inteftines, and made a part of what they difcharge. And when we confider the vaft Number of Glands in the Inteftines with the Outlets of thofe Vif- cera opening thereunto, and particularly of the Liver and Pancreas ; it will be no wonder that vaft Quantities, efpe- cially in full Conftitutions, may be carried oft 7 by one Purge.
As to thofe Purgatives diflinguiflVd by the Names of Chologogues, Hydragogues, Pblegmagogues, on a Suppofition of an ele&ive Quality therein ; they may be accounted for upon more intelligible Principles. For when the Dis- charges by Stool difcover an Over-proportion of any parti- cular Humours, it is to be fuppofed there was a Redundance of fuch an Humour, whofe difcharge any Irritation would occafion. Thus in proportion to the Proximity of fome Humours in the Inteftinal Tube, and the Difpofition of the Paffiges to convey them that way, do they require greater or leffer Vibrations, or Shakes of the Fibres to fetch them out.
For this Reafon, the brisker Cathartic?, which vellicate the Membranes moft of all, pump out, as it were, from all the Mefenteric Glands, and neighbouring Parts, their Contents, which becaufe they abound fo much with Lym- phatics, and vifcid watry Humours, make the Difcharges thin and watry.
Thofe which act. in fomewhat a lo'wer degree, yet irritate enough to deterge and draw out a great deal of mucous and vifcid Matter, which fometimes by lodgment and want of due Motion, changing into various Colours, occa- fions the different Names of Fblegm ot Choler . As theformer therefore pafs for Hydragogues, iodo the latter for Purgers of Phlegm and Choler. See Phlegm, Choler, %$o.
But there is another Principle befides that of a Stimulus, whereby a purging Medicine is enabled to anfwer its In- tention 5 viz. by ruling the Humours, and rendring them more fluid than before, whereby they are better fitted to pafs off by their proper Emunftories. — Thofe which confift of very fubtile and aftive Parts, are not fo fenfible in the larger Paffages, becaufe of the great Quantities of Matter which lays too great a Load upon them, and makes them unheeded ; but when they are got into the Blood in any considerable number, they divide and fufe thofe Cohefions, which obftruft, or move heavily along the Capillaries, and fcour the Glands, infoniuch that every Pulfation throws fomething through the inteftinal Glands, which goes away by Stool, that the refluent Blood had wafh'd away and brought back from all parts of the Body.
Of this kind are all thofe Cathartics, which are faid to flirge the Joints, and are prefcribed in Rheumatifms, and Arthritic Pains, as the Radix 'Turpeth'i, and all the Aloe- tics. — And this is the Reafon, why purging Medicines of this fort, are Co eafily changed into the moft efficacious Altera- tives > for an Alterative is a Cathartic in a lower degree, or of a more remifs Operation. Whatfoever brings fuch Par- ticles to a Secretory Orifice, which are fitted for its Paffage,
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oftener, eitner by accelerating the Blood's Morion, o P breaking it into more Particles of that particular Size and Inclination, will increafe the Secretion. According there- fore, to the difference of the Parts, where fuch Secretions are enlarged as the Glands of the Inteftines, Kidneys, or Skin j are the Medicines, which are the lnftruments there- in, call d either Cathartics, Diuretics, or Diaphoretics See Alterative, Secretion, &c.
Dr. gutney has madefome Improvements in the Doflri of r — £2
cuu.™.™ „, L „ vlt preparation, management, &c. in ■ D.fcourfe inferred in the <Philofi£h. Tranjitcl. The Sob ttance of which we cannot do better than here fubjoin.
In order hereto, it is to be premifed, i°. That all thofe parts of an animal Body which are vafcular, or thro' which any Fluid paffeth, from the Inteftines to the minuteft Fibre are the Seat of the Operation of Medicines. See Medi- cines-
i°. That thiswhole Courfe of Circulation, branimal Mo- tion, is naturally diftinguifh'd into three different Stages by the different Capacities of the Veffels, and Motions of their Contents, each having its proper Out-let ; and that thefe ate the Seat of the three Concoctions, fo ofen men- tion'd by phyfical Writers : the firil being the Scomach and Bowels, and having the Anus for its Emunaory ; the fe- cond all that Space within the Blood's Motion, fo far as it retains its ted Colour, having the Kidneys ; and the third, all beyond that Circuit, having the Skin for an excretory Organ. See Concoction, Emunctory, He.
- °. That every Medicine which caufeth Evacuation is,
in fome fenfe, a Purge. See Evacuation.
4°. That every Purge operates as a Diffolvent, by fifing the Juices, and increaling the Quantity fit for Expulfion s or as a Stimulus, by accelerating their Motions, fo as to bring the Matter fit for Expulfion, oftener to the feretory Out-let; or both.
Thefe Toptlata are only premifed in order to prove this grand Propofition, That a Change in the Bulks, Figures, and Motions of the component Particles of a purging Me- dicine, will change the Seat of its Operation, and fit it for exertion in the larger or fmaller Veffels, as thofe mecha- nical Affeclions are intended, or remitted.
For Illuftration hereof, it may be convenient to attend to the common way of making a Purge operate, more or lefs, than it otherwife would do.
Subftances, then, which are grofs and heavy, as thofe confifling chiefly of faline and earthy Particles 5 fuch as Tartar, Manna, and the like, when reduced fmaller by Triture, or repeated Solutions, operate more gently ; but when acuated by Acids, or any way made to expofe their Angles more plentifully to the Membranes, they become rougher, and looner take effect.
Refinous Medicines, as Scammony, Gamboge, Jalap, and moft of vegetable Production, are more violent, and* operate fooner, when they are more tenacious, and adhe- five, as in their Extracts; but gentler, when divided by hatd, btittle Subftances, fuch as Salt of Tartar, Sugar &c.
Medicines which have in their Compofition, Sulphur ;md Salt, are more or lefs rough, and fpeedy in their Operation, in proportion to their greater or leffer participation of the*
faline Ingredient, and the afperity of its Angles Of
this kind are moft Minerals, and their Preparations : It may be fufficient to inftance in the management of Anti- mony, and Mercury ; the fitft of thefe is by chymical Ana- lyfis known to be a Compofition of a fubtile Sulphur and Salt ; and the more the faline Part is fet loofe by Prepara- tion, and opening the Sulphur, as it is commonly term'd, the fpeedier, and with the greater vehemence will it operate; whereas in its more imperfect Preparations, when the Salts ate clofely wrap'd up in their native Sulphur, it will hardly work at all till it reaches the fartheft Wages of Cir- culation. See Antimony.
Mercury fer fe is little known as a Medicine, and its firft Preparation which makes it into Sublimate, fo loads it with faline SficuU, that it amounts even to a Poifon ; but the more thofe Spiculte are broken by Triture, Sublimation, VSc. the milder doth it operate ; and if to the comminu- tion of its Points be added a Sulphur fubtile enough to join it, it may be reduced to fo mild a Medicine, as not to be felt, but in thelaft Stage of Opetation. See Mercury, Salivation, He.
This fhortView may be fufficient to fhew, i°.That it is the too great Afperity, and Motion in a Medicine, that will not fuffer it to pafs the Stomach, without irritating it into fuch Convulfions, aswill throw it up again by Vomit. See Eme- tic and Vomiting.
a°.That a farther Comminution, and fmoothing its Figure, will gain it admittance into the Bowels, and caufe it to operate, as a proper 'Purgative, by Stool.
10 Z. 5°. That
