THE BILE. 159 



The Mucinous Body of the Bile. 



The mucinous body which is found in the bladder-bile of all 

 animals is apparently of a different nature in different animals. 

 The mucus of the human bile largely consists of true mucin, while 

 in ox-bile a mucinous nucleo-albumin is principally found. To 

 isolate this latter, the bile is precipitated with 5 times its volume 

 of absolute alcohol and immediately centrifugalized. The super- 

 natant liquid is poured off, and the sediment rapidly dried with 

 filter-paper and dissolved in water. By repeating this process the 

 substance can be obtained in a fairly pure form. Its character as 

 a nucleo-albumin becomes apparent on treating its neutral solutions 

 with a small amount of hydrochloric acid. A flocculent precipitate 

 then develops, which readily dissolves upon the further addition of 

 hydrochloric acid to the extent of 0.3 per cent. This solution re- 

 mains clear for a long time even when kept at the temperature of 

 the body. On digestion with pepsin, however, a separation of 

 pseudonuclein occurs. On fusing the dried substance with potas- 

 sium hydrate and sodium nitrate, an amount of phosphoric acid is 

 obtained which is greatly in excess of the amount required to satu- 

 rate all of the mineral ash that is present when calculated as 

 tricalcium phosphate. On boiling with a dilute mineral acid no 

 reducing-substance is formed, as in the case of true mucin. Acetic 

 acid precipitates the substance from its solutions, in the absence of 

 biliary acids ; but this precipitate, unlike that of mucin, is soluble in 

 an excess of the acid. 



The mucin proper which is found in human bile may be isolated, 

 as already described (see Saliva). 



The Biliary Acids. 



The biliary acids which are normally found only in the bile are 

 essentially compound amino-acids, which are formed through the 

 union of glycocoll on the one hand, and taurin on the other, with 

 a cholalic acid. In the bile of sharks Hammarsten discovered the 

 existence of a third group of biliary acids, which are rich in sul- 

 phur, and, like the conjugate sulphates of the urine, yield sulphuric 

 acid (scymnol sulphates) on boiling with hydrochloric acid ; at the 

 same time a substance is obtained which manifestly belongs to the 

 group of cholalic acids. Traces of these acids are said to occur 

 also in human bile. Of their chemical nature, however, nothing is 

 known. 



Under pathologic conditions, when the free outflow of bile is 

 impeded, owing to a swelling of the mucous membrane of the 

 common duct or to the presence of a calculus, resorption of the 

 bile takes place through the lymph-channels, and the secretion 

 thus finds its way into the blood. Jaundice then results, and in 

 such cases not only the bile-pigments but also the bile-acids can 

 be demonstrated in the general circulation. To the presence of the 

 latter is due the slow pulse which is so constantly observed in 



