180 
developed by the progressive discoveries of our 
‘sivas Predy conclude that the bile is 
secreted from venous blood ? 
The quantity of the bile is a question diffi- 
cult to decide accurately ; it would appear to 
be secreted most abundantly during digestion, 
when the augmented activity of the stomach 
would seem to be communicated to its neigh- 
bouring organ, the liver. Certainly it is eva- 
cuated from the gall-bladder into the digestive 
canal at that period. In animals which have 
been kept long fasting the gall-bladder is always 
greatly Sistenied. Schultz observed, in an ox 
which had been kept for some time without 
food, from twelve to sixteen ounces of bile in 
the gall-bladder, and in another, after digestion, 
from two to four ounces only. In a dog which 
had not eaten for some time he found five 
drachms, in another, after digestion, about two 
drachms. In a case of abscess of the liver 
communicating with the gall-bladder and 
lung, recorded by Dr. Monro, the whole 
of the bile flowed through the fistulous canal 
and was discharged by coughing, “ in proof of 
which,” he says, “ the feeces were of the same 
whitish colour and had as little smell as those 
of a person deeply jaundiced. The quantity 
of bile discharged by coughing was different at 
different times. It was always greater after 
meals, and especially for an hour or two after 
dinner. The quantity expectorated could not 
be measured with great accuracy from being 
mixed with mucus and saliva. The whole 
yori in twenty-four hours was from ten to 
fteen ounces; and, in this case, I had an 
opportunity of observing the effects of certain 
articles of food, and in particular of acids, of 
wine, and of different fruits, in increasing the 
quantity of bile.” 
Expulsion of the bile-—This process 1 have 
just shewn takes place more abundantly during 
digestion than at any other period. In all 
carnivorous and in most herbivorous animals 
there exists a peculiar provision for the col- 
lection of the bile during the period of ab- 
stinence, in a membranous reservoir, the gall- 
bladder. Some herbivorous animals, deprived 
of a distinct gall-bladder, have a compensating 
dilatation upon the hepatic duct. The use of 
this organ is to retain the bile until digestion 
demands its excretion. Those animals, there- 
fore, that are provided with it are such as 
rform the function of digestion at variable 
intervals. But in those whose digestion is con- 
tinuous, as is the case in many herbivora, the 
bile flows as it is secreted into the alimentary 
canal; being very probably provided more 
abundantly under the stimulus of a full sto- 
mach than during the abstinence from food or 
during sleep. In the contracted state of the 
duodenum the small and oblique opening of 
the ductus communis choledochus is closed to 
the passage of the fluid; it therefore regurgitates 
along the cystic duct into the gall-bladder. In 
the slight ascent along this tube it is facilitated 
by the spiral valve, which also serves to restrain 
its too sudden emission during spasmodic ac- 
tion of the abdominal muscles. As soon as 
the duodenum becomes filled with the chyme 
from the stomach, the opening of the ductus 
NORMAL ANATOMY OF THE LIVER. 
communis choledochus is less compressed. The — 
rears, of the a but more a 
arly the passage of the chyme along the py- 
lorus into the upper part of the duodenum, 
causes a gentle pressure upon the coats of th 
gall-bladder which favours its emission; | 
contents are gradually expressed, and flowin 
along the ductus communis choledochus 
mingled with the pulpy mass in the duodenum 
This explanation of the rocess seems to ha 
been entertained by Haller, and to have aris 
in his mind from the consideration of ana 
tomy of the serpent, where the gall-bl e 
far removed from the liver and is situated 
the space formed by the contraction of the p 
lorus and its termination in the small i 
tine. Neither do I consider its truth inys 
dated by those cases in which the gall-bh 
is partly imbedded in the liver, for in st 
instances that portion of the liver is compress 
which immediately covers the fundus of 
gall-bladder, or a of the gall-bladder 
exposed against which the duodenum m 
exert an Fe compression. Miill 
that the efferent ducts of glands are surroun 
by “ an extremely thin layer of muscular sul 
stance,” which, although not demonstrable an 
tomically, he thinks to be placed beyond dispu 
by physiological observations. “ contract 
power of the ductus choledochus in birds 
known to Rudolphi. By irritating mechaniea 
or by galvanism the ductus choledochus of 
bird just dead, I have frequently produc 
very strong contraction of it, which cont 
some minutes, after which the duct 
its previous state. I have often excited stre 
local contractions of the ureters likewise, b 
in birds and rabbits, by the application of 
powerful galvanic stimulus. Tiedemann 
has seen motions of the vas deferens of a horse 
eusue on the et of a stimulus. I 
appears indeed that periodic vermicular motio 
are performed by the efferent ducts, at le 
the ductus choledochus, in birds; for I hha 
once observed in a bird just killed, contraction 
of the duct occurring regularly in pauses € 
several minutes, the tube dilating again in t 
intervals ; and what was remarkable, the ¢o 
tractions took place in an ascending direction 
namely, from the intestine towards the liver: 
and this seems to throw some light on th 
mode in which the bile at certain times, it 
stead of being expelled into the intestines, i 
retained and driven into the diverticulum 0 
the duct, namely, the gall-bladder ; the con 
lete closure of the mouth of the duct cont 
utes perhaps to this effect. The discharge 
the bike frots the gall-bladder during dige stion 
results probably from the mere * ure of the 
surrounding parts, and the action of the ab- 
dominal muscles, while the mouth of the due 
is open: for I doubt if the gall-bladder is con- 
tractile ; I could produce no contraction ¢ 
in mammalia and birds even with the most 
werful stimulus of a galvanic Aad 
onro considers the middle coat of the gall- 
bladder in man to contain muscular fibres ; the» 
muscular coat in the gall-ducts of the dog and — 
horse are, he observes, quite distinct, and upon — 
irritation he has seen the gall-bladder contract 
por 
Con 
a 
