360 CONDITIONS INFLUENCING THE SECRETION OF BILE. 



filtered through the blood-capillaries, as the pressure within the bile- 

 ducts may exceed that in the portal vein. 



(2.) The quantity of bile was estimated by v. Wittich from a biliary 

 fistula, at 533 cubic centimetres in 24 hours (some bile passed into the 

 intestine); by Westphalen, at 453-566 grms.; [by Murchison, at 40 

 oz.]; Joh. Eanke, on a biliary-pulmonary fistula, at 652 cubic centi- 

 metres. The last observation gives 14 grms. (with 0'44 grms. solids) 

 per kilo, of man in 24 hours. 



Analogous values for animals are 1 kilo, dog, 32 grm. (1'2 solids) Kolliker, 

 H. Muller; 1 kilo, rabbit, 137 grm. (2'5 solids) Bidder and Schmidt; 1 kilo, 

 guinea-pig, 176 grms. (5 '2 solids) Bidder and Schmidt. 



(3.) The excretion of bile into the intestine shows two maxima 

 during one period of digestion; the first, from 3 to 5 hours, and the 

 second, from 13 to 15 hours after food. The cause is due to simul- 

 taneous reflex excitement of the hepatic blood-vessels, which become 

 greatly dilated. 



(4.) The influence of food is very marked. The largest amount is 

 secreted after a flesh diet, with some fat added ; less after vegetable 

 food; a very small amount with a pure fat diet; it stops during 

 hunger. Draughts of water increase the amount, with a correspond- 

 ing relative diminution of the solid constituents. 



(5.) The influence of blood supply is variable : 



(or.) Secretion is greatly favoured by a copious and rapid blood supply. The 

 blood-pressure is not the prime factor, as ligature of the cava above the diaphragm, 

 whereby the greatest blood-pressure occurs in the liver, arrests the secretion 

 (Heidenhain). 



(&.) Simultaneous ligature of the hepatic artery (diameter 54 mm.) and the 

 portal vein (diameter 6 mm.) abolishes the secretion (Rohrig). These two vessels 

 supply the raw material for the secretion of bile. 



(c.) If the hepatic artery be ligatured, the portal vein alone supports the 

 secretion (Simon, Schiff, Schmulewitsch, Asp). According to Kotfcmeier, Betz, 

 Cohnheim and Litten, ligature of the artery or one of its branches ultimately 

 causes necrosis of the parts supplied by that branch, and eventually of the entire 

 liver, as this artery is the nutrient vessel of the liver. 



(d.) If the branch of the portal vein to one lobe be ligatured, there is only a 

 slight secretion in that lobe, so that the bile must be formed from the arterial 

 blood (Schmulewitsch and Asp). Complete ligature of the portal vein rapidly 

 causes death. [The blood-pressure falls rapidly and the blood accumulates in the 

 blood-vessels of the abdomen. In fact, the accumulation of the blood within the 

 abdomen takes place to so great an extent, that practically the animal is bled 

 into its own abdomen (p. 176).] 



Neither the ligature of the hepatic artery by itself (Schiff, Betz), nor the 

 gradual obliteration of the portal vein by itself, causes the cessation of the 

 secretion, but it is diminished. That sudden ligature of the portal vein causes 

 cessation is explained by the fact, that in addition to diminution of the secretion, 

 the enormous stagnation of blood in the rootlets of the portal vein in the abdominal 

 organs makes the liver very anaemic, and thus prevents it from secreting. 



(e.) If the blood of the hepatic artery is allowed to pass into the portal vein 

 (which has, been ligatured on the peripheral side), secretion continues (Schiff). 



