566 



MECHANISM OF BILE SECRETION. 



cells, is not made 



o 



manifest 



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 



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 Eosenberg 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 Eosen- 

 1 tore'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 

 that after a meal of fats the bile secretion 



. Water Carbohydrates 



Fats Mixed Diet 



##** Proteids 



FIG. 48. Showing influence of 

 various food stuffs upon the 

 secretion of bile. 



the secretion of urea, but 



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, 



1 "Physiol. Chem.," S. 308. 



2 Arch. f. d. ges. Physiol. , Bonn, 1890, Bd. xlvi. S. 243. 



3 Bull. d. sc. med. di Bologna, 1894, Ser. 7, vol. v. 



4 " Rapporto tra la eleminazione dell urea e della bile." 



