U R E 



His herbarium contains no fpecimen anfwering to this de- 

 fcription, nor have wc ever feen any. 



II. U. Lappa^o. Bur Urena. (U. procumbens ; Linn. 

 Syft. Nat. ed. 12. v. 2. 462. Lappago laciniata ; Rumph. 

 Amboin. v. 6. 59. t. 25. f. 2 ?) — Leaves finuated, ferrated, 

 fomewhat heart -fhaped : hoary and downy, with a (olitary 

 gland beneatli. Outer calyx in five deep lanceolate feg- 

 ments. Prickles of the fruit elongated, cylindrical, many- 

 barbed. — Native of the Eaft Indies. The branches are 

 round, fubdivided, (lightly downy. Leaves on ihortilh 

 Italks, acutely lobed, clothed with ftarry down on both 

 fides, but moft hoary beneath ; their length about an inch 

 and a half. Fruit large and tumid, muricated with prickles 

 half a quarter of an inch long, each tipped with feveral pale 

 hooks. We fliould have little doubt of Rumphius's fyno- 

 nym, had there not been fo many different opinions concern- 

 ing it. Our defcription is taken from fpecimens to which 

 Linnseus, long after he pubhfhed his Sp. Plantarum, at- 

 tached the name of procumbens, fabricating from them a new 

 fpecific charafter, which Hands in the fecond volume of his 

 Syft. Nat., and is adopted by Willdenow ; but which is alto- 

 gether irreconcileable to the defcription of the original pro- 

 cumbens. 



12. U. viminea. Rhomb-leaved Urena. Cavan. Diff. 



335. t. 84. f. I. WiUd. n. 8 Leaves acute, ferrated, 



(lightly lobed ; rounded at the bafe, with a folitary gland 

 beneath : upper ones rhomboid or oblong. Outer calyx in 

 five deep lanceolate fegments. — Gathered by Commerfon in 

 Brafil. This feems next akin to the lall, but the leaves are 

 not finuated, nor of fo uniform an oblong figure ; they are 

 hoary beneath. Of the fruit we have no account. 



U. TyphaUa, Linn. Mant. 258, and U. kptocarpa, Suppl. 

 308, are referred by CavaniUes and Willdenow to Pavonia ; 

 (ee that article. 



Urena, in Gardtning, ccmprifes plants of the woody 

 perennial exotic kind, among which the fpecies cultivated are, 

 the angular-leaved urena (U. lobata) ; and the cut-leaved 

 urena ( U. finuata). 



Method of Culture. — Thefe plants may be increafed by 

 feeds, which (hould be fown on a hot-bed, or in pots plunged 

 into it, in the early fpring feafon. When the plants have 

 fome growth, they (liould be removed into feparate pots, 

 being replunged in a frefli hot-bed, requiring afierwards the 

 fame management as tender exotic plants. When placed in 

 the (love in the fpring, they ripen feeds the firil year, but 

 otherwife in the fecond, and feldom continue longer. 



They afford variety among other (love plants, by their 

 flowers, and the manner of their growth, fomc rifing high, 

 the others more procumbent. 



URENTIA, are fometimes ufed for medicines of a hot 

 or burning quality. See Caustic. 



VRESEN, in Geography, a fmall Dani(h ifiand in the 

 Great Belt ; 4 miles N. of Langcland. 



URETER, in y/na/omji, the tube which conveys the urine 

 from the kidney to the urinary bladder. See Kidney. 



URETHRA, the canal by which the urine palTes out of 

 the urinary bladder ; and through which the feminal fluid of 

 the male is conveyed into the vagina of the female. See 

 Generation. 



Urethra, Striaures of. A llrifture of the urethra may 

 be defined to be a preternatural diminution of the diameter 

 of a part of that canal. By the late Mr. Hunter, (Iriftures 

 of the urethra were divided into three kinds : firft, the true 

 permanent ftri£lure, arifing from an alteration in the ftruc- 

 ture of the paffage ; fecondly, a mixed cafe, compofed of a 

 permanent ftrifture and fpafm ; and thirdly, the true fpaf- 

 modic ilridurc. (See Trcatife on the Vcn. Difcafe, 

 6 



U R E 



F- III.) This mode of dividing thefc cafes fuppofes the 

 urethra to poffefs a natural power of contra£Uon and relaxa- 

 tion ; a circumllance which, though moft probably true, 

 and moft commonly beheved, is not univerfally admitted. 

 The doftriiie of Mr. Hunter, however, has been ably fup- 

 ported by the obfervations of his brother-in-law, fir Everard 

 Home ; and it has always appeared to us, that the fafts in 

 favour of the contractile power of the membrane of the 

 urethra are equally obvious and convincing. It may be dif- 

 ficult, and perhaps impoflible, fays the latter author, to 

 prove this membrane to be mufcular, either from its ap- 

 pearance, or from examination of its texture ; fince the pe- 

 cuHar ftrufture, upon which the contraftion of a mufcle 

 depends, has not as yet been afcertained. Other ftruftures 

 apparently membranous, and equally unhke the fafciculated 

 fibrous texture commonly met with in mufcles, are endowed 

 with a power of contrafting and relaxing, in a much greater 

 degree, than is ever found to take place in the membrane of 

 tlie urethra. The taenia hydatigenia ovalis, an animal con- 

 fifting of a femitranfparent membranous bag, met with in 

 the brain, liver, and omentum of fliecp, when taken from 

 its natural fituation, and kept in tepid w.iter, contrafts and 

 relaxes the different parts of its bag to a confiderable ex- 

 tent. ( See Pra6t. Obf. on the Treatment of StriAures, &c. 

 p. 15.) The mufcular ftruAure of the ureters cannot be 

 demonllrated, yet no one doubts that they poffefs a con- 

 traftile power. As is obferved in the article Kidney, of 

 this Cyclopaedia, their funftion of conveying the fecreted 

 urine from the kidney to the bladder requires the exercife 

 of tonic powers ; and the idea of this fluid finding its way 

 by the force of gravity, is not only repugnant to the laws 

 ot the animal economy, but is irreconcileable with obvious 

 phenomena. The adhefion of the fides of the tube, where 

 it penetrates the coats of the bladder, prefents an obftacle, 

 which can be overcome only by the exertion of fome force ; 

 and this obftacle is vaftly increafed in the diftended ftate of 

 the bladder, during which the fluid is conftantly finding its 

 way into this receptacle. 



In the fame manner, although the mufcular ftrufture of 

 the urethra cannot be demonftrated, yet many phenomena 

 are in favour of the affirmative, and, at all events, leave no 

 doubt of the canal poffeffmg a power of altering its diameter. 

 Here the funftions of the part, and certain fads remarked 

 in praflice, afford a better criterion than anatomy, which, 

 it is allowed, does not in this inftance give us any kind of 

 evidence. When the urine paffes out, the canal is large ; 

 when tiie femen is thrown out, it is fmall. When a portion 

 of its membrane is in an inflamed ftatc from gonorrhoea, its 

 furface is more readily ftimulated, and the irritation of the 

 urine makes it contraft fo much, that frequently the fluid 

 is voided only by drops. In this ftate, if the penis be im- 

 mcrfed in warm water, the urethra often becomes fuddenly 

 relaxed again, and the urine is more eafily difcharged. In 

 many cafes, the furgcon finds, when he attempts to intro- 

 duce ftimulating injeftions into the urethra, that they will 

 not pafs on towards the bladder, but bring on fo ftrong a 

 contradlion of the paffage, that they are rcjefted again with 

 confiderable velocity. 



The celebrated Soemmerring has explained the formation 

 of ftritturcs by a thickening of the difcafed part, and he does 

 not appear to entertain any belief in tlie fpafmodic nature of 

 thefe cafes. (See Abliandlung iiber die Schiiell und Lang- 

 fam todtlichen Krankheiten der Harnblafe, und Harnrohrc 

 bey Mannern ini hohen alter. Erankf. 1809.) Mr. Charles 

 Bell .ilfo contends, that the wiiitc condenfed fubftance, 

 which conftitutes the moft common kind of ftrifture, muft 

 be equally incapable of yicidnig to preiTurc and fpalmodic 



adion. 



