LIVER. 



tl.e ramifiontions oF the vena portanim ami the hepatic 

 artery. They comnuinicate frequently together, mul end 

 by numerous trunks in the thoracic duil, after pafling 

 through ditferent gland?. 



Tlie biliary duAs arife in all parts of the liver by capillary 

 extremities, which are too minute for our molt delicate 

 means of refearch. Thev unite together, in the manner of 

 veins, into larger and lartfer trunks, which at lall end in 

 producing two or three principal ones, quitting the liver 

 at the tranfverfe notch, and then united into a hngle tube, 

 of about a line and a half in diameter, called the hepatic 

 duft. 



All the branches of the hepatic duft in the liver, accompany 

 the divifions of the veiu portarum, and are inclofed with 

 them in tiic cellular covering already defcribed. They are 

 ^aiily dillinguilhed, on a fedtion, by the yellow tint which 

 they acquire from the tranfudation of the bile, and the ori- 

 fices arc then called pori biharii. Indeed, we may eafily dif- 

 tinguifh, on a cut piece of liver, all the veflels belonging to 

 it. The yellow colour and greater thickiicls mark the 

 tiliary tubes ; tlie coats of the arteries arc not quite fo thick, 

 and not coloured ; the branches ot the vena portarum are 

 next in order of thicknefs, and are remarkable for their cel- 

 lular covering ; the hepatic veins are the thinnefl. 



Whether the capillary beginnings of the biliarv dndis 

 come from the acini ot the liver, and concur with the cnpil- 

 lary blood-vefTels in furmmg thofe acini, is a point which we 

 reallv cannot determine. 



Of the peculiar tiffiie or parenchyma nf the liver. — The fiib- 

 ftance of the organ is next, in point of denlity, to that of 

 the kidney ; y«t it yields with tolerable facility to the pref- 

 fure of the finger. 



When we cut into itc fubHance, we obferve the colour 

 diftinguifted from that of the exterior by a flight yellowilh 

 tint. It is porous from the groat number of vefiels dillri- 

 buted through it, and feveral yellow points are dillinguilhed, 

 vhich are the fniall biliarv tubes. The different orders of 

 veflels may be recognized by the chara£ters already ex- 

 f I?'ined ; the veins contain more or lels blood, which may be 

 eafily fqueezed out. The cut furface is fmooth, and made 

 up of imall points alternately of a reddith-browii and an 

 cbfcure yellow. The fubliance of the organ may be eaJily 

 toi-n ; the furface is then unequal and granular, compofed 

 indeed entirely of imall granular bodies with every variety of 

 figure, about the fize of millet feeds, of an obfcure red co- 

 lour, and foft conliilence. Thefe are the acini of anat^imifts, 

 and are united together, as well as all the veflels that ramify 

 in the organ, by a fine cellular tiiTue. Long ccntroverlies 

 have exiited concerning their nature ; but we have nothmg 

 to add on this fubjeit to what we have Hated in the article 

 Gland. 



In faft, wc are entirely ignorant of the nature of thefe 

 fmall bodies, which compote the proper tiffue of the liver, 

 and we know no more concerning its jiiimite organiiation 

 than about tliat of other parts. We fee blood-vefftls both 

 cf the arterial and venous kind, a ptx;uliar order of veins not 

 found in other organs, lymphatics, excretory tubes, nerves, 

 fniall foft and reddifh granular bodies, cellular .tifTue to con- 

 nei£l all thefe together, and common coverings to infulate the 

 organ ; fuch is the account of our knowledge concerning 

 the organifation of this part. Chemillry does not difclofe 

 to us any thing more fatislaiSory ; we know that it is the 

 flowell of all jjarenchymatous organs in putrefat^ion, after 

 the kidney; that it lofes much of its weight, and acquires 

 Something of a fatty nature by drying ; that it is foftened 

 fcy <.43ullition ; diflbhed in fulphuric acid, which it tinges of 

 a deep violet colour ; and rendered coriaceous and greyilh in 



nitrous acid. But thefe fads do not much illuftrate its or- 

 ganiiation. We find, lallly, that difeafe produces in its 

 llruAure changes as numerous as they are diillcult of expla- 

 nation. 



The liver is covered by two membranes, a ferousand a cel- 

 lular one, which are very difierently arranged. 



The external is formed of peritoneum, and covers the 

 wJiole furface, except tlie pofterior edge, in the fituation rf 

 the coronary ligament, the excavation fi)r the inferior vena 

 cava, tliat for the gall-bladder, and the two fifTures of the 

 inferior furface. It relembies the peritoneum in genc?ral ; 

 is fmooth and polidicd on the external furface, and connedted 

 very clolely by the internal to tlie proper membrane of the 

 liver, except in the lituations already fpecified. 



'J'he other membrane, called by ijoemmerring membrana 

 celluiofa hepatis, lias been moll minntely defcribed by the 

 French anatomill.-, who aflign the difcovery of it to M. 

 Laennec. Boyer defcribes it as covering the external fur- 

 face of the organ, and moreover reflcded over the veflels that 

 enter it. Its internal furface corrcfponds to the tifiueofthe 

 liver, to which it adheres very clofely. It fends flieaths over 

 the veflels ; the mofl confpicuous of thefe is the capfula- 

 Gliifoni. already defcribed; but the hepatic veflels have one 

 clofely connected to them and to the furrounding fubliance 

 of the liver, and the umbilical vein in the fcctus is furnlflica 

 with a fimilar covering. This proper membrane of the liver 

 is thin, tranfparent, and of a {lightly yellow tint. It is 

 flronger than the peritoneum; hardly admits of extcnfion, 

 and exhibits nothing fibrous in its texture. It may be bell 

 fliewn in the lituations where it is not covered by peritoneum : 

 by maicing an incifion, and introducing the handle of a 

 fcaJpel, it may be eafily feparated from the fubliance of the 

 orgaiu 



If the hepatic artery be injccled, in a healthy liver, with 

 any fluid kind of injeftion, as fize coloured with vermilion, 

 iio point can be diicerned in the whole organ, more particu- 

 larly if the microfcope be employed, in which branches of 

 this veflel are not vifible- The fame obfervation may be 

 made concerning the vena portarum, the hepatic veins, and 

 the hepatic dudt. If the injeclion be pufhed farther, it will 

 pafsout of one of thefe veflels into the others; that is, it will 

 pafs from the hepatic artery into the vein of the fame name, 

 into the vena portarum, and into the biliary duft ; or, -vice 

 ■Dcr/a, from either of thefe into the artery, &c. Injeftions 

 do not pafs from the artery into the abforbents, unlcfs when 

 there has been an eifufion into the fubliance of the organ. 

 It is faid that the abforbents have been filled with liquors 

 throw'n into the vena portarum ; and that the fame circum- 

 ftance readily takes place where mercury is introduced into 

 the hepatic duft. 



Thefe fafts concur with the refult of the mofl careful in- 

 fpeclion, aided even by the microfcope, in proving that there 

 IS an uninterrupted palfage from one order ot veflels into the 

 other, and nothing of a cellular or veficular nature inter- 

 pofed between them. 



Of the appai-atus conntdeJ 'with the excretion of the lik The 



tube, which we have already defcribed, as being formed by 

 the union of all the excretory canals in the liver, under the 

 name of the hepatic duft, paflTes from the gTcat notch of the 

 liver towards the left, being at the fame time inclined {lightly 

 downwards and forwards, and is continued to the duodenum, 

 in which it opens. It runs between the two laminae of the 

 httle omentum, furrounded by fat and cellular tiffue, which 

 is generally dyed of a yellow colour by the tranfudation of 

 the bile. It hes on the anterior edge of this omentum, in 

 front and rather to the right of the veua portarum, with 

 wluch it is eitenHveiy in coutaft, and to the riglu of the 

 5 hepatic 



