EXCRETION 285 



which, as has already been mentioned, is often found in 

 gall-stones in combination with bile pigment ; whether 

 or not an increased consumption of calcium salts in the 

 food is followed by an augmented excretion of them in 

 the bile is still disputed. The question is one of interest 

 in relation to the dietetic treatment of cholelithiasis. 



The total volume of bile produced daily seems to 

 vary between 500 and 1,100 c.c. Its amount probably 

 depends upon the activity of the general metabolism, 

 but it is almost impossible to increase it by artificial 

 means. Diet has no appreciable influence upon it, nor 

 has the amount of water drunk. The effect of drugs is 

 very uncertain, and, as far as most experiments go, 

 negative ; but any agent which causes an increased 

 destruction of red corpuscles will, of course, increase 

 the excretion of bile pigments. Administration of bile 

 acids or dried bile by the mouth has been said to 

 stimulate the liver to form more bile, but this statement 

 is apparently based upon a misinterpretation of the 

 results of experiments upon animals or patients with 

 biliary fistulse. The greater richness of the bile observed 

 in such cases when dried bile is given by the mouth is 

 not due to the liver forming more natural bile, but 

 merely to its excreting that portion of the artificially 

 administered bile which has been absorbed from the 

 intestine. We are still, therefore, without a true chola- 

 gogue or hepatic stimulant. 



Bile is produced at a very low pressure not more 

 than 16 to 24 millimetres of mercury. One consequence 

 of this is that a comparatively slight obstruction in the 

 bile passages is sufficient to retard its escape, and may 



