BILE. 211 



being organic matters, and 10 per cent, mineral substances. It be- 

 comes more concentrated by a prolonged stay in the gall-bladder. 



The organic matters in bile are 1. The bile-pigment (the brown 

 and the green) already described (p. 101) ; 2. Cholesterine (see p. 

 75); and which, with fat and fat-acids, form 27 to 30 per cent, of 

 the solid residue. 



Among the mineral constituents of bile, the chloride of sodium 

 preponderates. There are also found some phosphate and carbonate 

 of soda, phosphate of lime and magnesia, and traces of iron and 

 magnesium. 



The amount of bile secreted in twenty -four hours is unknown. 

 Bidder and Schmidt's experiments on the lower animals would lead 

 to the conclusion that it is not less than 23 ounces 1 in the case of 

 an adult man weighing 140 pounds. It is increased by animal 

 food, in quantity, and at the same time in density. 



Fat, taken in abundance, increases it also. On the other hand, it 

 is considerably diminished by the carbonate of soda, and by febrile 

 diseases. Calomel increases it; but only so far as the water is con- 

 cerned the solid constituents remaining the same. 



The bile is constantly secreted ; but increases about three hours 

 after the reception of food, and so continues for some hours after- 

 wards. After prolonged abstinence it is reduced to one-fourth the 

 quantity of the secretion afforded in the twenty-fourth hour after 

 the last meal. If an animal is fed exclusively on fat, no more bile 

 is secreted than during fasting. The gall-bladder empties itself 

 in two and a half to three hours after taking food. 



Origin. There can be no doubt that the bile is formed in the 

 liver. 2 Not one of its constituents exists preformed in the blood of 

 the portal vein ; and icterus does not occur in any disease which 

 attacks the parenchyma of the liver, and thus entirely suppresses 

 the secretion of bile. The epithelial cells lining the terminal sub- 

 divisions of the hepatic ducts are the immediate agents of the 

 biliary secretion. Fig. 118 shows Kolliker's idea of the relations 

 of these cells to the "parenchymal cells" of the liver itself; the 

 ducts directly abutting upon the latter, as he believes; and Fig. 

 119, the secreting cells when isolated. The actual structure is, 



1 Todd and Bowman estimate the quantity at 54 ounces, containing 2 ounces of 

 solid constituents (pt. iv. p. 480). 



2 Except, perhaps, the pigment. (See p. 101.) 



