KIDNEY, 



The nerves, derived from the ganglia of the great fyrapa- 

 thetic, conftitute the renal plexus, of which the branches 

 furround the blood-veflels, particularly the artery, and pe- 

 netrate with it into the kidney. The kidnies fecm to be 

 hardly fenfible in the natural ftate : but difeafe, as, for ex- 

 ample, inflammation, devclopcs their fenfibility in a very 

 high degree. 



The external furface of the kidney is clofely invefted by 

 a peculiar membrane, fometimes called the capfule, which 

 adheres by means of /fiiort and very fine threads, but can be 

 feparated without much difficulty. It enters the notch, and 

 is conneiled there to the calyces and blood-vefTels It is 

 very denfe and firm, fenii-tranfparent, rather thicker than *he 

 peritoneum, and not divifible into laminar. Immerfion in 

 boiling water makes it curl up and become thicker. 



The ureter is tlie tube def!c:ned to convey the urine from 

 the kidney, commencing from tlie inner and lower part of 

 the pelvis of the kidney by a widi opening, fometimes called 

 infundibulura, and continued thence in a defcending courfe 

 to the inferior furface of the bladder, where it is not more 

 than an inch diftant from its fellow of the oppofite fide. 

 Its ordinary iize is about equal to that of a qnill, except , 

 towards the lower extremity, where it is lligbtly conti-adted ; 

 but it varies in this refpeft ni different fubjeds, and even in 

 different parts in the fame fubjeft. Commonly there is one 

 to each kidney, but fometimes it is double. 



From its origin it goes obliquely inwards and downwards 

 as far as the front of the iacro-iliac fymphyfis, where it is 

 feparated from the oppofite one by the breadth of the bafis 

 of the facriim. lu this part of its courfe the peritoneum 

 and the fpcrmatic velTels lie in front: the pfoas miifcle, which 

 it croifes at a very acute angle, is behind it. Lower down it 

 CrofTes the common iliac artery and vein. The right tube lies 

 parallel to the outer fide of the inferior vena cava. Several 

 fmall blood-veffeis are diftributed on it. At the bafe of the 

 facrum it pafTcs forwards, downwards, and inwards through a 

 large quantity of adipous fuhllance, and advances towards 

 the under furface of the bladder. Here it crofTes the vas 

 deferens, and is placed a little above and externally to the 

 veCcula feminalis, at which point it penetrates the bladder. 

 It runs obliquely between the coats of that organ, pafTmg 

 for about an inch from without inwards and from behind 

 forwards, between ;he mufcular and mucous coverings, and 

 then opening into the cavity by a very narrow orifice placed 

 at the poftcrior angle of the triangular fpace near the neck 

 of the bladder. 



The courfe of thefe tulies is the fame in the female ; they 

 prefent no peculiarities worthy of notice in the pelvis of this 

 lex. 



As the ureter is a continuation of the pelvis, we naturally 

 expeft to difcover in it the fame organization as in that 

 bag. Anatomids defcribe three coats; an exterior, tliin, 

 tranfparent, and of a cellular nature ; a middle, w+iich is 

 thicker, and gives to the part its colour and confidence; and 

 an internal mucous covering, continuous with thofe of the 

 pelvis of the kidney and bladder, and habitually moiftened, 

 like them, with a mucous fluid capable of defending it from 

 the adlion of the urine. Thefe flrata are, however, fo 

 clofely connefted, that it is almoll impoffible to exhibit 

 them dillinfi. The blood-veffels are derived fro.n the renal, 

 tlie fpcrmatic, the aorta and vena cava inferior, and the 

 ili^cs 



The ureters, as well as the pelvis and calyces of the kid- 

 ney, are very cxtenfible ; their ordinary functions probably 

 require the cxcrcife of fuch a property, as they mull be 

 fubjeft to various conditions of plenitude and einptinefs. 

 But difeafe elucidates this point molt clearly i when, the 



natural paffage of the urine is obftrutted by a ftone, or 

 when it is dift urbed by difficulties in the evacuation through 

 the urethra, the ureters are often enlarged very contiderably, 

 even in tome cafes almofl to the fize of a fmidl intelline, and 

 the pelvis, with its dependencies, undergoes an analogous 

 dilatation. 



Thefe parts do not feem to potTefs animal fenfibility in 

 their natural flate ; but that property is manifefted in them 

 to the highell degree, by the paffage of a ftone, v.liicli 

 caufes perhaps torture as exquifite as any difeafe ef any 

 organ in the body. 



Their funttion of conveying the fecreted urine from the 

 kidney to the bladder, requires the exerciie of tonic powers : 

 the idea of this fluid finding its way by the force of gravity, 

 is not only repugnant to the laws of the animal economy, 

 but is irreconcileable with obvious phenomena. The adhelion 

 of the fides of the tube, where it penetrates the coats ot 

 the bladder, prefents an obilacle, which can be overcome 

 only by the exertion of fome force ; and this obilacle is 

 va'.Uy increafed in the diflended ftate of the bladder, during 

 which the fluid is conllantly finding its way into the recep- 

 tacle. The only power in thi;- cafe, by which the requi- 

 fite end can be obtained, is a contraftion of th.e canal. 



Devehpimmt of the Kidney. — In the foetus all parts of the 

 urinary apparatus are remarkable for their conliderable ad- 

 vancement; and fome are diftinguiflied by confiderable pecu- 

 liarities of conformation and ilrufture. The kidnies are 

 vei-y large, furrounded at firft by a foft and reddilli cellular 

 tiffue, but covered, before the end of utero-geilalion, by a 

 fmall quantity of granulated fat : this is moil abundant be- 

 hind, fo that the peritoneum is almoft immediately in con- 

 taft with them in front. The external furface is tubercu- 

 lated at this time : anatomifts liave fometimes defcribed the 

 organ, as if the cones of tubular fubllance were imperfectly 

 conncfted together as yet, fo that each kidney might be 

 regarded as an affemblage of fmaller kidnies. Tliis repre- 

 fentation is not correft ; no traces of fuch diftinftion are 

 vifible in the interior ; and the tubercles of the outfide, 

 which correfpond to the bafes of the cones, feem to depend 

 on the cortical matter being not completely developed. 

 Some animals, as thofe mammalia which either live in or 

 frequent the water, have kidnies compofed of fmall kidnies 

 conneded by cellular fubftance. There is in thefe cafes a 

 large number of cones, each furrounded by a llratum of 

 cortical matter, and furniflicd with a calyx of its own : and 

 thefe feparate pieces are only united bv cellular fubftance. 

 We may conceive the human kidney to be formed in this way, 

 except that the feparate portions are blended into one mats : 

 and the diRinftion is only external even in the foetus. A 

 ftrufture of a defcription quite oppofite prevails in many 

 other animals, particularly in all the ferx of LinnvEus. 

 The kidney in them confiils of a fingle portion of tubular 

 fubilancc, with one papilla and calyx, and a fingle ilratum 

 of cortical matter. 



Wiiile the kidney retains this tuberculated exterior, the 

 proportion of cortical matter is fmaller than in the perfect 

 gland ; but the diftindtion between it and the tubular is well 

 marked : the papilla exhibit a very lively red colour. Tlie 

 gland at this time has confiderable firmnefs, particularly if 

 compared to the liver or fpleen. The capfule is very per- 

 feftly formed, and fep-irates eaf:iy. The calyces, pelvis, and 

 ureter are remarkable for their confiderable progrefs : the 

 latter, in particular, is nearly half as large as in the adult, 

 in a foetus of feven or eight months. Its fi:£e may be more 

 accurately eftimated if it be compared to the vas deferens, 

 which is like a flender nervous thread, recognizable only by 

 its whitenefsv 



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