Page:Cyclopaedia, Chambers - Volume 2.djvu/316

 OPI

( ssi )

OPI

r£l™ lfe requireS c °P ious b,eea!n S f " much as . °t^ ™ MiJ to abate immoderate Secretion, ar.rt o/hTHALMICS, Medicines proper for Difeafes of the ^S^-X^S^,SSSl ^ ''"'^ "'

Eyes ; as Ophthalmic Waters, Ophthalmic Powders, Oint- ments, SSc. See Eyes.

There is an excellent Ophthalmic prepared of Sugar of Saturn,

The fifth Pair of Nerves of the Brain, dividing into three Branches ; the firft is call'd Ophthalmic, becaufe it goes to the Eye : This again lubdivides into two Branches, after fending out feveral Twigs which encompafs the Optic Nerves, and are diflributed in the Choroids See Nerve

OPHTHALMOGRAPHS, that Branch of Anatomy which confiders the Structure and Compofition of the Eye ; the Ufe of its Parts, and the principal Eftefls of Vifion. Sec Eye.

Our Countryman, Dr. William Briggs, has published an excellent Opbthalmographia, W Flempms another.

The Word is form'd frotn the Greek »58»> lft ©-, Eye; and yfa$i, Defcriprion.

OPHTHALMOSCOPY, that Branch of Phyfiognomy which confiders a Perl'on's Eyes; to deduce thence the Knowledge of his Temperament, Humour, and Manners. See Physiognomy.

OPIATE, in Medicine, any Compofition wherein Opium is an Ingredienr. See Opium.

The Word is frequently alfo apply'd to Confections, Anti- dotes, and Electuaries ; tho fome fay 'tis only properly applicable to loft Compofitions : In which fenfe it is de- fined an internal Remedy, varioufly compofed of Powders, Pulps, Liquors, Sugar, or Honey, reduced into a foft Con- fidence. See Confection, Electuary, &c.

The Opiate of Solomon is a Compofition of great Fame, To call'd from one Solomon, a Phyfician, its Inventor ; and firll published by Laurence Soubert,

There are a particular kind of Opiates, call'd Incarnathes, for the Teeth and Gums, made of Alum, Sumach, Lig- num Aloes, Myrrh, Mattic, £;c. reduced into Powder.

Opi ates is alio ufed in the general for all Medicines given with an Intention to procure Sleep ; in which fenfe the Word is of the fame Import with Narcotics, Hypnotics, Soporifics, and Pacifies. See Sleep, Narcotic, Hyp- notic, c^c.

The Operation of Opiates, or the manner wherein they

And herein lies nes, in that the

the incraffating Quality of thofe MeoW., twitching Senfe upon the Membranes of the Lungs, Bowels, &c. being leffen A the /harp Humour is fuffer'd to lodge there ,n a greater Quantity, before it is To troublefome as to be thrown off and expell'd; ,t being all one as if there were no Irritation of thenar, ,f the uncafy Senfe thereof be not regarded by the M,nd. And thefe Effefts will all be beightned by the Mixture of the Op iaie Panicles witH the Blood ; which i is hereupon rarify',1, and diflends its Veffels, efpecially thofe of the liratn ; and this does Hill to a greater degree, leffen the Influx of the nervous Fluid 'to the lam, by preffing upon the Tubulg, or little Canals, through whicn it is derived. Whence the reafon of that Difficulty of breathing, which O£««occafion ; this Symptom being in- reparable from the Rarefaftion of the Blood in the Lungs.

OPINION, a probable Belief; or a doubtful, and un- certain Judgment ot the Mind. SeeEELiEF.

Opi ion may be flriflly defined the Affent of the Mind to fropofitions not evidently true at firit fight ; nor deduced, by neceffary Confequence, from others that are fo ; but fuch as carry the Face of Truth. See Truth, and Error, alloFAiTii.SSc

TheSchools define ir, Jffenful Imelleffus cum formidim de °pp»fito; An Affent of the Underflanding, with fome fear or dittrutt on the contrary part. Thus the Logicians fay, that Demonitraton begets Science, or Knowledge; and probable Arguments beget Opinion. See Knowledge and Probability.

Wherever the Mind's Acquiefcence in a Truth propofed to it, ,s accompanied with any Doubt, this is what we call an Opinion. See Douisti ng.

Flato makes Opinion a Medium between Knowledge and Ignorance; clearer and more exprefs than Ignorance; yet more obfeure and unfatisfying than Knowledge. See Ig- norance.

OPISTHOTONOS, in Medicine, a kind of Convulfion, wherein the Body is bent backwards, fo as to form, as it were, a Bow ; in wh.ch fenfe the Word is ufed in oppofition to Emprojthotono,, wherein the Body is bent forwards. See Convulsion.

The Opisthotonos arifes from a tonic Motion of the Mufcles produce their Effect m the Body, Dr. Qumcy thus lays of the pofterior Parts of the Body ; efpecially thofe on

in u ■ c ■ i, „ the back of the Head.

All Pam is i a Sttmulus on the Part affefled, and is at- The Word is compounded of the Greek omi* backward tende-d with Contractions of the pained Membranes, which behind, and ™ K „, tender to ftretch bend ^^"^

Senfation in any yart

° n „: h l°: h ! t -_ hand ' ?', f arur f> °l a delightful Head of the black Poppy,' ^dafaWdslnfpiffafed™ See

. s accompanied with a fmooth Undu- lation, and e.ily Reflux of the nervous Juice towards the Brain. ^ This is, as it were, the Entertainment of the Mind; with which being taken up, it doth not determine the Spirits to the Organs of Motion : that is, there is fuch a Relaxa- tion of the mufculsr Fibres, and fuch a Difpofition of the nervous Fluid, as is neceffary to Sleep. See Pain, tgc.

Now, 'tis (hewn that an agreeable Senfation produced in the Stomach, together with a diftenticn of its Membranes, is the immediate Caufe of that Slecpinefs, to which we are inclinable alter Eating ; the one engaging the Mind, the other acting on the Body. For Pleafure amufes the Soul, and the Fulnefs of the Veffels in the Brain, checks and hinders, in fome mcafure, the derivation of the nervous Juice into the Organs.

ISiow, to apply this ; a moderate Dofe of an Opiate, ufually tranfports People with a pleafing Senfation, to that degree, that, as they often exprefs themfelves, they ate in Heaven ; and tho they do not always fleep, (which pro- ceeds from the premutation of pleafing Images to the Mind fo flrongly, that, like Dreams, they do over-engage the Fancy, and fo interrupt the State of Reft) yet they enjoy lo perfect an Indolence and Quiet, that no Happinefs in the World can furpafs the Charms of fo agreeable an Extafy.

Thus we have from thefe Medicines, but in a far more eminent degree, all thofe Effefis which are obferred to follow upon that grateful Senfe in the Stomach, which a moderate Fulnefs produceth. For no Bodies are fo fit and able pleafingly to affect our fenfible Membranes, as thofe which confill of volatileParts,whofe Activity is tempered and allay'd by the Smoothnefs of fome which are lubricating and oily ; for they lightly rarify the Juices of the Stomach, and caufcapleafantTitillation of its nervousCoat, whereby there is induced an agreeable Plenitude, and the Mind is entertained with Ideas of Satisfaction and Delight.

And thus, we eafily fee upon what Mechanifm the other

Poppy.

WhentheJuiceflowsofitfelf, thro' Incifions made in the Poppy Heads, it is properly call'd Opium ; when drawn by Expreflion, it affumts this Name of Meconium. See Me- conium;

The'difference between the Qualities and Virtues of the two Juices, is very confiderable : The former is preferable on all accounts ; but it is exceeding rare ; the Turks, among whom it is produced, and who make great ufe of it never allowing it to be exported : fo that it is the latter that IS ordinarily ufed among us, and fold for Opium.

'Tis moftly brought from the Levant and Cairo ■ gene- rally very impure v the Levantines, to ftortcn their La- bour, and to have the more Juice, drawing it equally from the Heads and the Leaves of Poppies, by Exprcffion, and then reducing it to the thicknefs of an Extract by Fire

It mull be- choTen dry, the fmoorhelt, and blackefl pofl.be, of adrowly fmell, and neither rugged, norflicky, nor all in a Mafs. "

'Tis a popular Error, that there is any fuch thing as white Opium-, tor tho' the Juice as it runs from the Heads of the Poppies be of a Mill-colour, it always becomes of a very deep brown as it thickens. Wherever it is found yellowifh or foft, tis a fign the Juice has not had Fire enough.

Prepared Opium is call'd Laudanum ; of which there are two Ktnds: the one We; extrafted by means of Rain- Water, andSptrttofWine: The other Compound, call'd Laudanum Opiatum ; wherein there enter feveral other In- gredients. See Laudanum.

The Ufes of Op„,m are to footh Pain, to excite Sleep, to flop Vomittng and Loofeneffes. Its Dofe is from half* Grain to two Gtams. Some Petfons, who have much habi- tuated themfelves to it, can take 5 o or 6a Grains. Charas lays, he has taken ia Grains himfelf; and adds, he knew one who made no fcruple of 3<r. And in the Phih

E^^^A^^^^i ™^*5ZZ^&^1ti&2&

Evacuations, igc. proceed not only from the Mind's being taken up with a pleafing Senfe, whereby it is diverted from a difagreeable one ; but all Pain being attended with a Contraction of the Part, the Relaxation of the Fibres, which they caufe, eludes and deftroys the Force of the Stimulus.

in three days time, took 102 Grains.

It raifes the Spirits, occafions agreeable Senfations, and

has much the fame efTeS with Wine or ftrong Spirits. The

Turks ordinarily take to the quantity of a Drachm when

8 G they