BILE. I 5 I 



mortem bile is variable in color. It is very difficult to determine 

 accurately the amount of normal bile secreted during any given 

 period. For an adult man it has been variously estimated at from 

 500 c.c. to noo c.c. for twenty-four hours. The specific gravity 

 of the bile varies between i.oio and 1.040, and the freezing-point 

 is about 0.56 C. As secreted by the liver, the bile is a clear, 

 limpid fluid which contains a relatively low content of solid matter. 

 Such bile would have a specific gravity of approximately i.oio. 

 After it reaches the gall-bladder, however, it becomes mixed with 

 mucous material from the walls of the gall-bladder, and this proc- 

 ess coupled with the continuous absorption of water from the bile 

 has a tendency to concentrate the secretion. Therefore the bile 

 as we find it in the gall-bladder, ordinarily possesses a higher 

 specific gravity than that of the freshly secreted fluid. The specific 

 gravity under these conditions may run as high as 1.040. 



The principal constituents of the bile are the salts of the bile acids, 

 bile pigments, neutral fats, lecithin, phosphatides and cholesterol, 

 besides the salts of iron, copper, calcium and magnesium. Zinc 

 has also frequently been found in traces. 



The bile acids, which are elaborated exclusively by the hepatic 

 cells, may be divided into two groups, the glycocholic acid group 

 and the taurocholic acid group. In human bile glycocholic acid 

 predominates, while taurocholic acid is the more abundant in the 

 bile of carnivora. The bile acids are conjugate amino-acids, the 

 glycocholic acid yielding glycocoll, 



GEL-NIL, 



COOH, 



and cholic acid upon decomposition, whereas taurocholic acid gives 

 rise to taurine, 



CH 2 -NH 2 



CH 2 -SO 2 -OH, 



and cholic acid under like conditions. Glycocholic acid contains 

 some nitrogen but no sulphur, whereas taurocholic acid contains both 

 these elements. The sulphur of the taurocholic acid is present in the 

 taurine (amino-ethyl-sulphonic acid), of which it is a characteristic 

 constituent. There are several varieties of cholic acid and there- 

 fore we have several forms of glycocholic and taurocholic acids, 



