NORMAL ANATOMY OF THE LIVER. 



179 



bmnches of the portal vein, and the secretion 

 of bile therefore might still have been derived 

 from venous blood." 



" M. Simon and Mr. B. Phillipps have in- 

 ferred from experiments which they performed, 

 that the bile is secreted from the blood of the 

 portal vein. But Mr. Phillips found that 

 after the vena portae had been tied the secretion 

 of the bile still continued, though in di- 

 minished quantity ; and he concludes, there- 

 fore, that it is formed both from arterial 

 and venous blood. He perceived no change 

 in the biliary secretion when the hepatic artery 

 was tied." 



The cases recorded by Wilson, Abernethy, 

 and Lawrence are interesting, but they do 

 not appear to me to affect in the slightest de- 

 gree the arguments on either side of the pre- 

 sent question. It is true that it might be 

 asserted in behalf of Miiller's opinion, that the 

 blood sent to and circulating in the liver was 

 arterial, and that from this alone bile was 

 secreted, for in both cases bile was found in 

 the gall-bladder, while the vena porta emptied 

 itself into the vena cava. On the other hand 

 it was ascertained by Kiernan in the only one 

 of the three cases in which the liver was pre- 

 served, that the umbilical vein (hepatic portal) 

 was pervious, of considerable size, and rami- 

 fied as usual through the portal canals and 

 terminated as usual in the lobular venous 

 plexus. Now, although the hepatic portal 

 vein (umbilical) did not obtain its accustomed 

 supply of blood after the placental circulation 

 was arrested, from the abdominal portal vein, 

 yet there is no reason for supposing that it did 

 not collect the venous blood from the capillaries 

 of the arteries supplying the coats of the ex- 

 cretory ducts and other vessels. Again, the 

 transmission of the remaining portion of the 

 arterial circulation through the vaginal, the 

 interlobular, and lobular arteries must have 

 seriously affected its arterial character if it have 

 not indeed altogether converted it into venous 

 blood. Although Mayo, who took part in the 

 examination of this liver, observed upon this 

 point that " it cannot be supposed that the 

 arterial blood, in its passage through the vasa 

 vasorum into the branches of the umbilical 

 (hepatic portal) vein underwent the usual 

 change into venous blood ; and it was still, he 

 contended, arterial blood, though less pure in 

 character, which was conveyed through venous 

 canals into the secreting part of the liver." 



Now it may be fairly presumed thai blood 

 which is not arterial must be venous ; but it 

 must at the same time be admitted that the 

 normal degrees of arterialisation are various in 

 individuals, and different in different regions 

 of the body at the same moment ; so that no 

 satisfactory argument can be sustained upon an 

 assumption of the sub-arterial character of the 

 blood. I would rather suggest another train 

 of reasoning. The abdominal portal vein re- 

 turning blood possessed of peculiar properties 

 from the chylopoietic viscera terminates in a 

 rare anomaly in the inferior cava, so that the 

 portal blood is mingled with the general venous 

 current of the system. The lungs receiving 



this blood exert their appropriate influence in 

 separating from it a portion of the noxious ele- 

 ments with which it is combined ; but it cannot 

 be supposed that this blood will return to the 

 heart as pure in character as that which has 

 circulated in the usual way through the other 

 depurating organ, the liver. No; it still con- 

 tains the elements from which bile may be 

 secreted, and a larger portion than usual is 

 therefore sent to the liver, that this secretion 

 may be eliminated. Hence we cannot treat 

 the blood thus flowing into the liver from the 

 aorta in a much larger current than natural 

 (" in ordinary cases one principal artery is 

 found in each canal ; in this case two, and in 

 some places three arteries of equal calibre were 

 found in each canal") as mere arterial blood 

 destined for nutrition alone ; but we must re- 

 gard it as a fluid bearing in its course the ele- 

 ments of the bile ; and therefore, whether it be 

 poured through the capillary channels of the 

 lobular venous plexus, or through those of its 

 own developing in the substance of the lobules, 

 it is nevertheless an abnormal influence which 

 cannot be tested by man's decision, but is part 

 of the compensating principle so admirably 

 displayed by nature in all her operations. 



With regard to the evidence of experimental 

 operations upon living animals, this must at 

 all times be unsatisfactory and inconclusive 

 from the difficulty of observing and apprecia- 

 ting the consequences of the experiment, and 

 from the morbid condition impressed upon the 

 animal by the serious nature of the operations 

 themselves. Those which have been performed 

 are favourable to the conclusion that the bile is 

 separated from the blood of the portal vein. 

 But I have little faith in such experiments ; 

 after the ligature of the portal vein, the animal 

 lives but a short period ; the blood arrested in 

 its current is conveyed through the medium of 

 inosculations into the general venous circula- 

 tion, and then, as I have above suggested, if 

 the animal survive sufficiently long, the bile 

 may be secreted from the fluid which contains 

 it, viz. from the arterial blood. 



Cuvier entertains the opinion, that the bile 

 is secreted from venous blood, as may be per- 

 ceived in the following passages: "Le foiedes 

 animaux vertebres a en effet un caractere qu'il 

 ne partage avec aucune autre glande ; c'est que 

 sa secretion est alimentee par du sang veineux; 

 par du sang qui a deja circule, et qui n'est pas 

 retourne au coaur, ni par consequent au poumon. 

 Cetle circonstance a lieu, non-seulement dans 

 des animaux a circulation double, ou tout le 

 sang doit repasser par le poumon, avant de se 

 rendre aux parties, le foieexcepte; mais encore 

 dans les animaux a circulation simple (les 

 reptiles), ou une si grande portion du sang 

 arteriel n'a point retourne au poumon, et tient 

 par consequent de la nature veineuse ; c'est 

 presque alors du sang deux fois veineux qui se 

 rend dans le foie." May we not, therefore, 

 from the powerful arguments afforded by anato- 

 mical investigation, and from our knowledge of 

 the compensating energies aroused by nature 

 in cases of anomaly, may we not, at least 

 until weightier reasons to the contrary shall be 



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