i 
NORMAL ANATOMY OF THE LIVER. 
branches 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 porte 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 that 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. {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 
fare anomaly in the inferior cava, so that the 
portal blood is mingled with the general venous 
current of the system. The lungs receiving 
179 
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 curreft 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 foie des 
animaux vertébrés a en effet un caractére qu’il 
he partage avec aucune autre glande ; c’est que 
sa sécrétion est alimentée par du sang veineux; 
par du sang qui a déja circulé, et qui n’est pas 
retourné au cceur, ni par conséquent au poumon. 
Cette circonstance a lieu, non-seulement dans 
des animaux 4 circulation double, od tout le 
sang doit repasser par le poumon, avant de se 
rendre aux parties, le foie excepté ; mais encore 
dans les animaux 4a circulation simple (les 
reptiles), oX une si grande portion du sang 
artériel n’a point retourné au poumon, et tient 
par conséquent 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 
N 2 
