240 THE BILE. 



feebly alkaline. When it is filtered so as to separate mucus, it 

 does not decompose, and can be kept for a long period of time. 



The chemistry of bile was long involved in the greatest 

 obscurity, as it is a fluid which, under the influence of re- 

 agents, is very easily decomposed, and many substances which 

 are the products of such decomposition were considered as 

 essential constituents of it. We mainly owe our knowledge 

 of the composition of bile to the researches of Strecker. 



The bile contains about 16 per cent, of solid constituents; 

 these consist of resinous acids combined with soda, of colour 

 ing matter, of cholesterine. neutral fats, besides certain mineral 

 matters. 



Bile Acids. If we examine the bile of the ox we shall 

 find that it contains two very remarkable acids, the one crys- 

 tallizable, the other non-crystallizable ; to the first the name 

 glykocholic acid is given; to the second that of taurocholic 

 acid; these acids are found in the bile of most animals, 

 though not of all. They are obtained by evaporating bile 

 to dryness in a water bath, making an alcoholic extract, and 

 then adding a large excess of ether. A bulky white precipi- 

 tate falls, which consists of glykocholate and taurocholate 

 of soda. This soon assumes a resinous appearance, and in a 

 few hours crystals shoot up, these are glykocholate of soda, 

 and the uncrystallizable portion consists of taurocholate of 

 soda. 



If the ether be poured off, the precipitates dissolved in 

 water, and acetate of lead added, glykocholate of lead is pre- 

 cipitated ; if the precipitate be now separated by filtration, 

 and sub-acetate of lead (3 Pbo, C 4 H 3 3 ) added to the 

 clear liquid which filters through, a white precipitate of 

 taurocholate of lead falls. From the two lead salts, glyko- 

 cholic and taurocholic acid can respectively be obtained, by 

 suspending them in water, and passing a current of sulphur- 



