JOP
which elfc muft have happened from fuch frequent tile. By their flexibility, the contiguous furfaces are always nicely adapted to one another, and the friction diffufed equally over the whole ; by their elafticity the violence tif any mock which may happen from running, jumping, or other violent motions, is broken and gradually fpent ; and as the courfe of the cartilaginousfibres appears calculated chiefly for this laft ad- vantage, we need only, to illuftrate it, to reflect upon the dif- ference of riding a chamber horfe of wood, and a real one, whofe motions are foftened in all refpec"ts by the cartilages placed in the Joints.
The infenftbility of the articulating cartilages is wifely con- trived by the great author of our frame, lince it is wholly owing to this that the neceflary motions of the body are per- formed without pain.
An ulcerated cartilage is generally allowed, by the beft chi- iurgica! writers from Hippocrates to the prefent time, to be a very troublefome difeafe, and one that is more difficult to cure than a caries of the bones ; and that When a cartilage is defbroyed, it is never to be recovered again, is alfo a gene- rally eitablifhed opinion. Hildanus in particular, in treating of the difeafes of thefe parts, has obferved, that where a car- tilage is by any means deftroyed, nature ufually fupplies its place by a callus thrown out from the bone, and that thus a bony anchylofis, or immoveable continuity, is produced in the place of a moveable Joint. In the examining the difeafed Joints, either after death or amputation, Mr. Hunter ob- ferves, that he ufually found, according to the nature and ftage of the difeafe, the cartilages in fome parts reddifh and lax, and in others foft and fpongy ; or that they were raifed Up in blifters from the bone, or quite eroded, and perhaps the extremities of the bones carious ; and finally, fometimes a bony anchylofis formed, as Hildanus reports ; but that he riever faw, or indeed heard of, art exfoliation from the fur- face of the cartilage. Now if we compare the texture of the cartilages, and their morbid appearances together, all thefe difeafed ftates will admit of as rational folution, as thofe of perhaps any other part of the vitiated ceconomy. Phil. Tranf. N°. 469. p. 521.
It appears from maceration of the cartilages, that their tranf- verfe fibrils are extremely tender and difioluble, and that the cohefion of the parts of the ftrait fibres is ftronger than their cohefion with the bone. When a cartilage, therefore, is inflamed, and foaked in purulent matter, the tranfVerfe, or connecting fibres, will fooneft give way, and the cartilage will become more or lefs red and foft. If the diforder goes on a little longer, the cartilage does not throw off a flough, but feparates from the bone where the force of the cohefion is leaft, and where the difeafe foon arrives, by reafon of the thinnefs of the cartilage. When the bone is thus expofed, the matter of the ulcer, or motion of the Joints corrodes or abrades the bony fibres, and if the conftitution is good, thefe will moot out a callus, which either cements too-ether the oppofite bones of the articulation, or fills up the cavity of the Joint, and for the future prevents all motion : but if unfor- tunately the patient labours under a bad habit of body at the time, the malignancy having got root in the bone, will gain ground every day, and the caries will fpread, till at laft the only relief will be found the cutting off the limb.
Joint Water, a term ufed by our farriers, for what the old writers in medicine have called hydarthros ; a running of a clear ichor from the Joints, when they are either wounded or ulcerated ; it is common in the difeafes of horfes.
JOINTEE, in the manege. See the article Handful.
JOINTRESS, or Jointeress, ihe that hath an eftate fettled upon her by the hufband, to hold during her life, if fhe fur- vives him.
JON, in natural hiflory, the name of a gem defcribed by PHhy, and faid to be brought from the Eaft Indies j he defcribes it as being of a purple or violet colour, but rarely very deep in the tinge. It feems to have been a fpecies of amethyft.
JON.E Pijds, the Jonas Fijh, a name given by many authors to the common fhark, the cams carcharias of authors. It has this name from an opinion, that it was the fifh which fwallowed up the prophet of that name. But there are manv objections to fuch an opinion. See the articles Canis and Lamia.
JONKS, or Jonqiies, in {hip-building, veffels very common in the Eaft Indies, about the bignefs of our fly-boats but differing in form of building, according to the various methods of the nations in thofe parts.
JONTHLASPI, in botany, the name of a genus of plants the characters of which are thefe : The flower is of the cru- ciform kind, confiding of four leaves. The pifK] arifes from the cup, and becomes at length a fiat orbicular clypeated fruit, containing only one cell, which holds a flat and orbi- cular feed.
The fpecies of Jsnthlafpi, enumerated by Mr. Tournefort, are thefe: 1. The hoary difcoide mountain Jonthlafpi, with yellow flowers : And 2. The little fpiked lunated Jonth- lafpi. The firft of thefe is called, by many authors, fimply ntblafpi, and the other a Iwiaria. Tourn. Inft. p. 210.
IO P^AN, among the anticnts, an exclamation ufed on ac- count of a victory, or fome profperous event, Hoffman
I P E
thinks that U Paran is a contraflion of the Hebrew jaL from Jehovah, and nJS, refpexk ; and was the fame With tehovah Ptmxh, i, e. Dominus refpicM in not. Something;' like this exclamation (till remains among the SjWwisS i people of the Weft Indies, who on any joyful occafion fre- quently cry out To Peho. Hoffm. Lex. in vac. JOURNCHOPPER3, in our old writers, regrators of yarn ; which formerly, perhaps, was called Joun. They are men-
T nv n ,i' n , the ' Stet - 8 Hen - 6 - c ' 5- Bl """' Cow - JU* (Qitf.)_ This paffion has been found to increafe the perfpiration and urine of human bodies; See the article
PERSPIRATION.
JOZO, in zoology, the name of a fmall fea-fifh, of the fea- gudgeon or rock-fifh kind, common in the Mediterranean, and called gobius albus by fome authors. It is fmaller than any other fpecies of the gobius, and has larger and rougher icales. It is of a paler and fomewhat blu- iln colour, and the rays or nerves of its foremoft back fin itand out beyond the edge of the fin itfelf, in form of hairs or bridles. Its fides are divided by a line running along each, from the gills to the tail, compofed of fmall ohlone black fpots. All the fins in this fpecies are edged with blue, and the belly-fins are wholly blue. It is brought to market at Rome and Venice. mUugbUs Hift. Pifc. p. 207
IPECACUANHA (Cycl.)-Thc bark of Ipecacuanha is faid to be preferable to its root, as an emetic ; afling equally well, and with equal fafety in a fmaller dofe, either in powder, or nifufion. Six grains of the bark, infufed for a night in an ounce and a half of old rhenifh, proves a good emetic. See Phil. Tranf. N°. 476. Sea. 10.
The brown Ipecacuanha yields, by diftillation, a fmaller quantity of oil than the grey, and the laft portion of the fpirit which comes over with the oil, on urging the fire to the greateft violence, tho' it be confiderably acid to the tafte, yet does not feem to contain lefs, but rather more volatile par- ticles than the fpirit drawn in the fame manner from the grey. On mixing the fpirits of both kinds alfo with fait of tartar, the volatile parts of that from the brown, efcape with more rapidity than thofe from the fpirit of the grey, and affect the nofe more fenfibly.
It is rational to conclude from hence, that if the brown Ipe- cacuanha contains lefs oil than the grey, it alfo contains lefs refm ; and that as this laft portion of fpirit contained more volatile parts, it muft naturally be expected that it mould prove more violent in its operation than the grey. This obfervation alfo, which is countenanced by fact, may in fome degree favour the opinion of thofe who afHrm, that the purgative virtues of medicines are excited by a volatile fait, and that they are more or lefs violent, as they contain more or lefs of this fait.
The brown Ipecacuanha, as well as the grey, will afford two forts of extracts, a refinous and a faline one ; but both thefe are yielded in a fmaller quantity from the brown than from the grey, and confequently the refiduum is alway greater from the brown. Eight ounces of the grey Ipecacuanha yield, with fpirit of wine, ten drams of the refinous extract; the fame quantity of the brown, treated in the fame manner, yields only fix drams. From the refiduum of this quantity of the grey kind, thus divefted only of its refin by the fpirit, there may be procured, by a Watery folvent, two ounces of a faline extract ; but the refidue of the fame quantity of the brown will yield only five or fix drams of this extract, by the fame treatment. The refidue of the grey, thus divefted of its refinous and faline parts, will weigh four ounces ; and the refidue of the brown, after the fame treatment, will weigh near fix ounces; Hence it is very evident, that the active principles are much more abundant in the grey than in the brown kind of this ufeful root.
If the procefs of this analyfis be varied, and the watery men- ftruum ufed firft, the proportion of the faline extract will be greatly incteafed by it, and that of the refinous greatly di- minifhed ; eight ounces of the grey Ipecacuanha, thus treated, yielding three ounces and a half of faline extract, and only thirty-fix grains of the refinous one afterwards by fpirit of wine ; and the fame quantity of the brown yielding one ounce and three drams of the faline extract, and only twenty- four grains of the refinous one, by means of fpirit of wine afterwards ufed. From all this it is eafy to" perceive, that the brown Ipecacuanha contains much lefs of the active parts, and much more of the terreftrial than the grey ; and yet it is equally certain from trial, that the brown is much more vio- lent in its operation than the grey.
This feems a perplexing fort of paradox ; but to explain it we muft remember, that the virtues of medicines are not to' be meafured by their bulk nor their weight, the moft power- ful of all acting in the fmalleft quantities. It has been ob- ferved, that the laft portion of fpirit drawn from the brown is more pungent and ftrong than that from the grey j and probably this part of the root has as much power to irritate the internal parts of the interlines as the refinous parts. Small dofes of Ipecacuanha arc recommended in diarrhoeas of a more fimplekind, as well as in dyfenteries ; andinthefluor albus, we hardly know a better medicine.
IPECATI
