A B S 



operation for an empyema is defcribed in its proper 



place. 



From what has been faid in the foregoing paragraphs, it 

 will not be difficult to determine on the plan of treatment in 

 other calcs ot abiceh. The pnncipal authors to be conl'ulted 

 on thisfubjecl are Sevcrinus, Hiidanus, Wifcman, Heifter, 

 Van Swieten, Sharp, Pott, Bell, and Kirkland. Some curi- 

 ous cafes are alfo related, or refenrd to, in the Bibliothc- 

 que Choilie de Mjdeciue ; — the compilations of Man'/ctus, 

 Beniftein, and James ; — the Memoirs and Tvanfaflions of 

 different learned Societies ; — and in the works of Bonctus, 

 Foreftus, Lufitanus, I'lJpiu?, Hildanus, Moi-gagui, Horllius, 

 Stalpart VanderWiel, &c. &c. 



ABSCISSE, Abscissa, in Con/Vj, a part of the diame- 

 ter or tranfverfe axis, of a conic feftion, intercepted between 

 the -virtex, or fome other fixed point, and a fcniiordinate. 



Such are the lines AP, AP, &c. [Tab. Conies, fg. 20.) 

 intercepted between the vertex A, and the femiordinates 

 PM, PiVl, &;c. which are called ahfc'ijj'es, of the Latin ah- 

 Jcindcre, to cut off ; as being parts cut off from the axis. 

 Others call the-.n/agiita, q. d. arrows. 



Ahfc'ilp, in a more general fenfe,is a part or fegment of a line, 

 terminatedatfome certain point, cut ofFby an ordinate toa curve. 

 As the abfcifTemaycommeace either at the vertex of the curve, 

 or at any other fixed point ; it may be alfo taken either upon 

 the axis or diameter of the curve, or upon any other line 

 drawn in a given pofition. Hence there may be an infinite 

 number of variable ablciifes, temiinated at the fame fixed 

 point at one end, whilil the other end of them is at any 

 point of the given line or diameter. In the parabola, each 

 ordinate has one abfciife; in the ellipfe, or circle, it has two, 

 lying on the oppofite fides of it, and in the hyperbola alio 

 two, both of which lie on the fame fide of it. It may be ob- 

 ferved, in general, that a line of the fecond order, or a 

 curve of the firft kind, may have two abfcifles to each ordi- 

 nate ; a line of the third order may have three abfcifles to 

 each ordinate ; a line of the fourth order may have four ; 

 and fo on. The ufe of the abfcitfe is, in conjunftion with 

 the ordinate, to exprefs the nature of the curves, either by' 

 fome proportion or equation including the abfciffe and its 

 ordinate, with fome other invariable line or lines ; and hence 

 eveiy diifjreut cui-ve has its own peculiar equation or propor- 

 tion by which it is expreffed or defined. When the nature 

 and properties of curves, are expreffed by algebraic quantities, 

 the ablciffe is commonly denoted by the letter x. 



In the paralola the ablcilTe is a third proportional to the 

 parameter and fcm'ordinate ; and the parameter a thud pro- 

 portional to the abfciffe and femiordinate. 



In the eVipfr, the fquare of the femiordinate is equal to 

 the rectangle of the pai-ameter into the ablciffe, fubtrafting 

 another rectangle of the fame abfciife, into a fourth propor- 

 tio)ial to the axis, parameter, and abfciffe. 



In the hypcrhola, tlie fquares of the femiordinates are to 

 each other as the reftangles of the abfciffe into another line, 

 compofed of the abfciffe and the tranfverfe axis. See Conic 

 fiaion. Ellipse, Hyperbola, and Parabola. See alfo 

 Circle and Curve. 



ABSCISSION, in Rhetoric, is a figure of fpeech, when 

 beginning to fay a thing, we break off fhort, as fuppofing the 

 matter fufficiently fignified, by what has been already faid. 

 Cicer. ad Heren. lib. iv. cap. 77. 



For an inflance : one cf her fex, age, and beauty, to be 

 feen alone, at fuch an hour, with a man of his character — I 

 need fay no more. 



Ahf-iffionV, a fpecies of elmpsis, or SUPPRESSION. Scali- 

 ger dlftinguifhes it from prscilion and fufpenfion. 



A B S 



Abscission, in Snrgfry, denotes the aft of taking away 

 fome morbid or fuperfluous part by an tdged inftrumcnt. In 

 this fenfe alilcilTion amounts to the fame with the Greek 

 acToxown. Cowper fpcakr, of the abfcininn of aleg ; which is 

 more properly called amputation. The abfciirion of the 

 prepuce makes what we call circumcision. Abfciffion of 

 the ears is a kind of legal punidiment infliftcd on perjury. 

 In fome countries they alfo practifc abfeinion of the nofe on 

 traitors in an army, as a punifhment reputed worfc than 

 death. 



Abscission is more properly iifed for the operation of 

 cutting away fome foft part of t'iie body, wlien depraved or 

 grown hurtful. In which fer.fe, abVcillion difltrs from 

 amputation, in that the latter is of a folid or bony part, 

 the former of a flefhy or membranous one ; yet they are 

 fometimes confounded. We fay the ableillion of a muf- 

 cle, lip, cheek, or the like. Mr. Shipton gives an in- 

 ftance of the abfciffion of a portion of the intelkincs not be- 

 ing mortal. Phil. Tranf. N" 2?.3. 



Chelelden, aid fome later fiirgeons, have removed fe- 

 veral inehe^ cf mortified inteflii e iu cafes of I'langulated 



HERNIA. 



Abscission is fometimes nfed by mcJicn! ivriters io dc' 

 note the fudden termination of a difeafe in death, before it 

 arrives at its deehne. Celfus frequently ufes the terms ali- 

 fcijfa vox, to exprefs a lofs of voice. 



Aflrologers alfo fpcak of an ahjaiflon of the hght of a planet, 

 by another planet outftripping it, and joining a third before 

 it. Abfciffion is held a deterioration. 



ABSCONSA, a dark lanthorn ufed by monks at the ce- 

 remony of burying their dead. 



ABSENCE, in SiOts Law, is applied to a judgment 

 pronounced, when a perfon cited before a court does not 

 appear. No perfon can be tried criminally in ahfcnce. 



AB.SENTEE, in HJiory, denotes a perfon, who is abfent 

 from his ftation, employment, or countrj'. The term 

 has been commonly applied to Irilhmen, who poffefs 

 eflates in Ireland, and do not refide in the country. A 

 parliament under this denomination was held at l)ublin, 

 8 Hen. VIII. 



A15SIN THII^W<?na, a fpecies of phal^ena found on 

 the Absinthium. 



ABSINTHITES, Absinthiac, or Absinthiated, 

 fomething tinged or impregnated with the virtues of aljliilhi' 

 urn, or WORMWOOD. 



Bartholin mentions a woman whofe milk was become ahfin- 

 thiated, and rendered bitter as gall, by the too liberal ufe of 

 wormwood. Adt. Med. torn. ii. 



Viiium ahfinthites, or poculum alfnthiatum, wormwood 

 wine, is much fpoke of among the a-cients, as a wholefomc 

 agreeable drink, and even an antidote agamll dninkLnnefs ; 

 though fome have charged it with being oflenfive to the 

 head, and liable to caufe fevers, cephalalgies, vomitings, 

 uterine fluxes, &c. Ray alfo makes it a preventive of ve- 

 nery. According to the common account, it is made by in- 

 fufing the leaves of the plant in a quantity of wine. But 

 Fehr fhews that it fhould rather be prepared by fermentation, 

 in order to coiTcft the crudities of the plant, and call forth • 

 its volatile fait. Paulli prepares it even witiiout (i/yn/L-rum. 

 Dr. Bowie prefers the aqua ahfmihhes, or wormwood- 

 water, taken in a fmall quantity after meals, to the 

 wine ; as being lefs liable to uffecl the head, and fill it wuh 

 vapours. 



ABSINTHIUM, in Botany, is compounded of the pri- 

 vative particle a, and 4.1W0,, t!i.'ccla:io, pl.nj'urc, alludin.; t : !ie 

 difagrecabie taite oi this, piaiit. See ARTtmsiA and \\' ( k m- 



2 WOOD, 



