KIDNEY. 



tione which fill the intervals of the different portions of the 

 tubular matter. Thefe fepta have been called the fle(hy 

 columns of the kiJney : they grow thinner as ttiey approach 

 the pelvis, round which there is always found fome adipous 

 fubitance. Their number depends upon that of the pa- 

 pilli. The renal arteries are dillributcd almoft entirely to 

 the cortical fubftance : injedlions thrown into thefe veffels 

 penetrate it moil eafily, and colour it througiiout : hence it 

 has been concluded to be of a nature entirely vafcular. 

 Some anatomiils have admitted the exiftcnce of very fmall 

 . glands in this fubllance, connefted to the blood-veflcls as 

 grapes are to their ihlks ; thefe are technically named acini. 

 On tearing the cortical fubftance, fmall granulacions are 

 obferved on the torn furface, and minute granular bodies are 

 feen in great abundance throughout this part of the kidney, 

 where it has been minutely injefted. Thefe are confidered 

 as the glands in queftion, while fome contend that they 

 are only convoluted blood-velTels. For an account of the 

 controverfy on this matter, fee Gland. The minutencfs 

 of the objefts does not allow us to arrive at any fatis- 

 fatlory conclufion concerning their intimate ftruaure. 



The tubular or uriniferous, called alfo the Itriated fub- 

 ftance, is lighter in its colour, more denfe and folid than the 

 cortical. Injeftions do not penetrate it, but leave it in 

 general quite colourlefs. It is compofed of a vail number 

 of fmall tubes (tubuh uriniferi) united into conical fafci- 

 culi of unequal fi/.e. The rounded bafes of thefe fafci- 

 Guli are turned towards the exterior of the kidney, and 

 prefent diverging llrias, which are loit in the cortical fub- 

 ftance : their apices are directed towards the notcli. Thefe 

 fafciculi are every where furrounded by the cortical fub- 

 ftance, except at their apices, which are embraced by the 

 infundibula. Each of thefe points forms a conical papilla, 

 pierced by numerous fmall apertures, which are the openings 

 of the tubes juil mentioned. 



The papillae, therefore, are fimply the points of the cones 

 ■which conllitute the tubular fubftance : their number varies 

 from five to eighteen. Generally there is a Tingle papilla 

 for each cone ; fometimes two cones are united hy one 

 papilla, which is then larger ; two papillx are very feldom 

 found on one cone. Their form and length are very various ; 

 they may be fhort and rounded, or long and pointed. They 

 are of a tolerably bright red colour, but fometimes rather 

 pale, while the reft of the tubular fubftance is redder, or even 

 of a violet hue at the balls of the cones. Their furface is 

 fmootli, foft to the touch, and probably covered by a fine 

 membrane. The orifices of the uriniferous tubes are feen 

 on it, and as thefe are much lefs numerous than the ftris 

 of the tubular fubftance, probably feveral of the fine tubes 

 unite together before they terminate. Compreflion of the 

 kidney caufes the urine to tranfude at thefe pores ; and 

 the urine may be cxpreffed in like manner, when the papilix 

 have been divided by a feclion perpendicular to the courfe 

 of the tubes. 



From the preceding defcription of the two fubftanccs 

 which compofe the kidney, it appears, that the cortical per- 

 forms the fecretion, and tliat the tubular, completely uncon- 

 cerned with this funclion, has the oflice of tranfmitting 

 the fecreted fluid. Thus it differs from all other glands 

 of which the component fubftance is identical throughout. 



That the arteries of the kidney arc entirely dillributed 

 in the cortical matter is evident from anatomical injettions : 

 the exad mode in which they are connefted to the uri- 

 niferous tubes hardly admits of being unravelled. The 

 arteries feem to be continued towards . the cones, where 

 thev are joined to the cortical matter, and injedioqs often 

 pafs from them into the uriniferous tubes, Vihich arc then 

 • Voi,. XIX. 



feen running in ftraight lines, and converging towards the 

 papillx. Ruyfch and others found that water, quickfilver, 

 fuct, wax, and air, thrown into the renal arteries, would 

 come out at the pores of the paplllx, wliich is a ftrong ar. 

 gunient for the exillence of continuous tube.«. A further 

 proof of the fame ciicumttance has been drawn from tiie 

 pafiage of attual blood in many inftances by the urinary 

 paftages. 



The bafis of each papilla is embraced by a fmall mem- 

 branous tube, into the cavity of which the apex projects. 

 Thefe calyces, or infundibula, are furrounded externally by 

 fome fat, and are lefs numerous than the p-^pillie, becaufi: 

 two or three of the latter arc fometimes furnilhed with a 

 fingle tube. They are collected ordinarily into three trunks, 

 which come refpedtively from the upper, middle, and lower 

 parts of the kidney. Thefe three trunks open at the notch 

 into the pelvis : lometimcs a greater number of branches 

 opens into this membranous bag. The pelvis is placed at 

 the deepeft part of the notch, behind and between the di- 

 vifions of the renal artery and vein. It is moft capacious 

 in its middle, narrower at the two ends, and continued below 

 _ into the ureter. The openings of the trunks formed by 

 the union of the calyces, and of the ureter, are obferved on 

 its inner furface. Thefe are fimple openings without any 

 valvular apparatus. Sometimes there are two pelves to a 

 fingle kidney. 



The pelvis and calyces are compofed of a firm, white, 

 and opaque membrane, connefted by a lo;>fe cellular texture 

 to the furrounding organs, and having a fmooth mucous 

 furface internally, continuous with that of the ureter, a!id 

 with the covering of the papill.c. Its ftrufture i« denl'e, 

 and not very vafcular ; of its properties and adlion we know 

 nothing. Bichat and Boyer diftinguilh three ftrata in this 

 membrane; an exterior, derived from the capfule of the 

 kidney ; a middle, or proper membrane, continued at the 

 bafes of the papilUe into the fubftance of the organ ; and an 

 internal, or mucous coat. 



The arteries and veins of thefe glands will be defcribed 

 in the articles concerning thofe vefiels ; we have only to 

 point out a few circumftances here concerning them. The 

 renal arteries arifc nearly at right angles, and p.xfs through 

 a ftiort courfe before they arrive at their deftination. Tlicir 

 diameter io very confiderable in projjortion to the volume of 

 the organ. It is Ihewn by fome calculations, the refults of 

 which cannot be received with very implicit confidence, 

 that one-fourth or one-third of the blo;;d of the abdominal 

 aorta goes to thefe glands, confequenlly, a very large pro- 

 portion of the whole mafs. Hence the whole of the blood 

 will have paftcd through the kidnies in a few pulfations of 

 the heart. They are covered and accompanied by the renal 

 veins ; both vefTcls divide near the kidney into fevcnd 

 branches, which enter the notch and penetrate into the or- 

 gan, accompanied by nerves and l;iiiphaiics. All thffe 

 parts are furrounded by a loofe cellular tin"ue, continuous 

 apparently with that contained in the notch. The proper 

 membrane of the kidney adiieres to thefe fafciculi. The 

 large branches occupy the intervals of the pajullx, and fol- 

 low a winding courfe round the cones ; the .fmnller ramifica 

 tions form arches in the cortical fubftance, from the con 

 vexity of which numerous ramilications are dillributed in 

 that fubftance. They feem to terminate about thejuntiioi 

 of the cortical and tubular parts by uriniferous tubes. The 

 veins have a difpolitiou analogous to that of the arteries. 



The lymphatic veflcls, dillinguiftird into fupcHu-ial and 

 deepfeated, communicate fiequeiilly. They follow t!ie 

 courfe of t!ie blood-vcifels, pafi out at the notch, jnd go to 

 the lumbar glands. 



5 C '1'l.e 



