5 66 
MECHANISM OF BILE SECRETION. 
BILE 
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been observed by various investigators. The most careful observations 
on the influence of food in bile secretion are those recorded by Hoppe- 
Seyler. 1 The experiments were made on a dog with a permanent 
biliary fistula, and they show that within an hour after food the flow of 
bile is slightly and temporarily increased. It is very probable that 
this initial increase is simply due to reflex stimulation of the gall bladder 
and bile passages, expelling the bile already secreted. Four or five 
hours after a meal the flow is enormously increased, the amount of 
bile solids rising with the amount of bile. The extent of this accelerated 
flow indicates that it is actually an increased secretion. How far it 
is due to the increased vascularity of the abdominal viscera, and 
how far to the stimulating action of absorbed material on the liver 
cells, is not made manifest by the experiments. About nine or ten 
hours after a meal there is a secondary 
increase, not so marked as the first, but 
lasting for two or three hours, and accom- 
panied by a still more marked rise in the 
excretion of solids. The cause of this is 
unknown. 
As to the special influence of the 
various constituents of the food, our know- 
ledge is somewhat defective. The re- 
searches of Rosenberg 2 and of Barbera, 3 
on dogs with a permanent fistula, show an 
increase in the secretion of bile and of the 
bile solids after proteid food. The latter 
observer states that carbohydrates have 
also a certain effect in increasing the secre- 
tion of bile, but that their effect is very 
small indeed. Both observers find that 
the administration of fats very markedly 
increases the bile flow ; but while in Rosen- 
berg's experiments the flow of bile under 
the influence of fats was greater than with 
proteids, in Barbera's the increase was most 
marked on a diet of flesh. 
The accompanying chart (Fig. 48) gives 
a summary of Barbera's observations. 
In another paper Barbera 4 shows that 
the excretion of bile after a meal of pro- 
teids or carbohydrates runs parallel with 
the secretion of urea, but that after a meal of fats the bile secretion 
increases out of proportion to the urea. 
The slight increase in the secretion following the administration of 
carbohydrates is probably due to the vascular dilatation. The more 
marked increase after fats may be related to their more prolonged 
digestion, and the correspondingly greater and more sustained dilatation 
of vessels. The increase after proteids is in part due to the same cause, 
but may also be due to the increased functional activity of the liver, 
O 3 6 9 12 hours 
Water Carbohydrates 
Fats Mixed Diet 
* * * * Proteids 
Fig. 48. — Showing influence of 
various food stuffs upon the 
secretion of bile. 
"Physiol. Chem.," S. 308. 
Arch./, d. gcs. Physiol., Bonn, 1890, Bd. xlvi. S. 243. 
Bull. d. sc. med. di Bologna, 1894, Ser. 7, vol. v. 
" Rapporto bra la eleminazione dell urea e della bile." 
