200 
EXPKIUMKNTS ON DIGESTION. 
view to the clearing up of this point. After having tied the ductus 
choledochus in some young cats, he destroyed them at different 
periods after the operation; and then examined the state of the 
aliments in the stomach and intestines, and particularly the nature 
of the fluid contained in the lymphatic vessels of the small intes¬ 
tines and in the thoracic duct. He found no change in the digestion 
of the aliment in the stomach; but when the bile could no longer 
flow into the intestinal canal, the chyle ceased to be formed at the 
expense of the chyme—in fact, there w^as no chyliform fluid either 
in the lymphatics, or the small intestine, or the thoracic duct. He 
concluded from this that the bile was necessary to the formation of 
the chyle. 
Anxious to know the result of a mechanical obstacle to the 
flowing of the bile into the intestinal canal, and to examine for our¬ 
selves the conclusions of Brodie, we have instituted a series of 
experiments on living animals; but we have preferred the dog, on 
account of his more patient endurance of pain, and consequently 
the more easy and perfect accomplishment of our object. 
After different unsuccessful attempts, we adopted the following 
method of tying the ductus choledochus, as the simplest and the 
surest. 
We selected for our experiments strong and healthy dogs, not 
overburdened with fat, and who had not been fed during the seven 
preceding hours. They were laid on their backs, and well secured 
by cords, as well as held by assistants. The hair was shaven from 
the region comprised between the umbilicus and the abdominal ex¬ 
tremity of the sternum. The operator, standing on the right of 
the animal, effected an incision, about an inch and a half in length, 
on the linea alba, and penetrating to the peritoneum. He then 
cut through this membrane with considerable caution, and intro¬ 
duced his finger into the wound—searched for the anterior surface 
of the stomach—followed it as far as the pylorus, which was easily 
recognized, and thus reached the duodenum. This intestine in 
the dog, not being, as in man, covered by a transverse portion of 
the colon, w^as easily secured by the bent finger, and thus drawn 
outward. He then turned it so that its convex border was directed 
towards the left side of the animal, after which he searched for the 
ductus choledochus, which appeared through the superior folding 
of the mesentery, in the form of a whitish cord. 
If the dog was fat, this duct was sometimes so covered with the 
adipose matter of the mesentery, that there was considerable diffi¬ 
culty in finding it, and it was scarcely possible to get at it without 
Avounding some of the bloodvessels. This circumstance sometimes 
prevented us from completing our operation : but, otherwise, hav¬ 
ing effected a small incision through the superior fold of the me- 
