172 



NORMAL ANATOMY OF THE LIVER. 



vessels, and in those of the excreting ducts and 

 gall-bladder ; the lobules were coloured with 

 the blue injection ; the red was confined to 

 their circumference, and appeared in points 

 only. This experiment was varied by inject- 

 ing the portal vein and its branches as far only 

 as the entrance of the latter into the lobules, 

 the lobules thus remaining uninjected. The 

 injection propelled through the arteries had 

 now free access to the uninjected lobules, and 

 no exit by the injected portal vein ; and the 

 artery having no communication with the he- 

 patic veins, the injection had no exit by these 

 vessels : the lobules however were not better 

 injected in this than in the preceding experi- 

 ments. From these experiments I conclude, 

 that the secreting part of the liver" "is supplied 

 with arterial blood for nutrition only. As all 

 the branches of the artery of which we can 

 ascertain the termination, end in branches of 

 the portal vein, it is probable that the lobular 

 arteries terminate in the lobular venous plex- 

 uses formed by that vein, and not in the intra- 

 lobular branches of the hepatic veins, which 

 cannot be injected from the artery." Miiller, 

 who published upon this subject previously to 

 the discoveries of Kiernan, and was therefore 

 not aware of the exact distribution of the ves- 

 sels, was deceived by this free communication 

 between the hepatic artery and portal vein. 

 He conceived, with the older anatomists, that 

 the arterial blood was mixed with the venous 

 blood of the vena ports, in a capillary network, 

 " vascula ultima reticulata," common to the 

 three bloodvessels of the liver, the hepatic ar- 

 tery, portal vein and hepatic veins. Observing, 

 moreover, in the injected preparations of Lie- 

 berkiihn,* that the " vascula ultima reticulata," 

 the lobular venous plexus of Kiernan, appeared 

 as well rilled when the injected fluid was 

 forced into the hepatic artery, as when intro- 

 duced through the portal or hepatic vein, he at 

 once decided that the artery must pour its blood 

 directly into this plexus. Hence he writes, 

 " Vascula ultima reticulata sanguinem tarn ab 

 arteriis quam a vena portarum accipere, ve- 

 nisque hepaticis reddere, ex hisce argumentis 

 conclude: Post injectionem in arteriam hepa- 

 ticam non minus quam in venam portarum aut 

 venas hepaticas factam, eadem communia vas- 

 culorum minimorum retia replentur, quod ex 

 injectionibus exsiccatis Lieberkuhnianis, Bero- 

 lini asservatis, facile quisquis sibi persuadebit." 

 Having recourse himself to an extremely im- 

 perfect experiment, the injection of water into 

 the hepatic artery, and finding that this fluid 

 returned by the portal vein, and possibly by the 

 hepatic vein, he became convinced of the com- 

 munications of all the vessels in the " vascula 

 ultima reticulata," and added another argument 

 to the injections of Lieberkuhn in favour of 

 his opinion ; for he says, " Injecti liquores co- 



* Having, through the kindness of Mr. Listen, 

 had an opportunity of examining with the micro- 

 scope some of the injections of Lieberkuhn of dif- 

 ferent tissues, I can bear testimony to their beauty 

 and wonderful minuteness, and can fully appre- 

 ciate the deservedly high estimation in which they 

 are held among the physiologists of Germany. 



lorati ex alio vasorum ordine facile in alium 

 transeunt, qualis frequens Halleri veterumque, 

 Walteri, denique et Rudolphi eel. extat expe- 

 rientia. Ipse equidem transitum aquae lim- 

 pidae et coloratae saepius observari." Now with 

 regard to the injections of Lieberkuhn, I can 

 only repeat with Kiernan, that if' the lobular 

 venous plexus or " vascula ultima reticulata" 

 were filled, actually, from the artery, the 

 only route which the injection could have 

 taken must have been through the capillaries of 

 the excretory ducts and vasa vasorum, and then 

 through the portal vein. But with regard to 

 the water experiment, I am quite satisfied of 

 its utter inadequacy to elucidate so delicate a 

 point as that under discussion. In my own 

 experiments, made with a view of assuring my- 

 self of the nature of these plexuses, I have not 

 been content with my injection unless I could 

 distinctly trace with the aid of the microscope 

 each capillary vessel from the interlobular vein 

 to the intralobular vein, and this I have never 

 failed to do in a successful injection from the 

 portal vein ; or in the opposite course when the 

 hepatic veins have been filled. But in the 

 most successful injection from the artery, when 

 the capsular arteries have been beautifully filled, 

 I have never observed more than a few red 

 points in the circumference of the lobules. 

 There is, however, in the consideration of this 

 question, one circumstance which appears to 

 have been altogether overlooked by Miiller, 

 but which seems to me to be fatal to the opinion 

 which he entertains with regard to the distribu- 

 tion of the arterial blood. The ducts are abun- 

 dantly supplied with blood from the arteries ; 

 indeed to so great an extent, that in a well- 

 injected liver their coats appear to consist almost 

 wholly of the ramifications of minute vessels. 

 Now if the aggregate of the surface formed by 

 the ducts, which is thus covered with vessels 

 supplied from the artery, be considered, it must 

 be evident that very little can be left for the 

 " vascula ultima reticulata." And if con- 

 jointly with this fact, the difficulty of injecting 

 the lobules from the artery be considered, it 

 must be admitted that Miiller carries his dogma 

 somewhat too far, in asserting without limita- 

 tion " that the arterial blood of the hepatic 

 artery and the venous blood of the porta be- 

 come mixed in the minute vessels of the liver." 

 The hepatic veins return the whole of the ve- 

 nous blood from the liver to the general venous 

 circulation. They commence in the centre of 

 each lobule by means of a small vein, the 

 intralobular, which collects the blood after its 

 circulation through the lobular venous plexus. 

 The intralobular veins pour their current into 

 the sublolndar veins, and these latter unite to 

 form the hepatic trunks, which terminate in the 

 inferior vena cava. The hepatic differ from the 

 portal veins in being more immediately in con- 

 tact, and more closely connected with the sub- 

 stance of the lobules. Thus the intralobular 

 veins are embedded in the substance of each 

 lobule, and the sublobular inclosed in canals 

 formed by the bases of the lobules, and there- 

 fore by that part which is uninvested by the 

 lobular capsule. The hepatic trunks differ 



