XI.] THE BILE. 87 



LESSON XI. 

 BILE. 



1. Use ox-bile obtained from the butcher, and, if possible, human 

 bile. 



(a.) The colour in man is a brownish-yellow, in the ox greenish, 

 but often it is reddish-brown when it stands for a short time, 

 Note its bitter taste, pecuHar smell, and specific gravity (loio- 

 1020). 



(b.) It is alkaline or neutral to litmus paper. 



(c.) Pour some ox-bile from one vessel to another, and note that 

 strings of so-called mucin connect one vessel with the other. 



{d.) Acidulate bile with acetic acid, which precipitates mucinoid 

 substance coloured with pigments. Filter off this precipitate. Test 

 the filtrate. 



(e.) It gives no reactions for albumin. 



(/".) Add hydrochloric acid and potassic ferrocyanide. A blue 

 colour indicates the presence of iron. Test for chlorides and other 

 salts. 



{(/.) Fresh human bile gives no spectrum, although the bile of 

 the ox, mouse, and some other animals does. 



2. Bile-Salts or Bilin (glycocholate and taurocholate of sodium). 

 (a.) Concentrate ox-bile to one-fourth of its bulk, mix with 



animal charcoal in a mortar to form a thick paste. Evaporate to 

 complete dryness over a water-bath. 



(b.) To the dry charcoal-bile mixture, add five volumes of abso- 

 lute alcohol. Shake the mixture from time to time, and after half 

 an hour filter. To the filtrate add much ether, which gives a 

 white precipitate of the bile-salts. If no water be present, some- 

 times the bile-salts are thrown down crystalline; but not unfre- 

 quently they go down merely as a milky opalescence, which quickly 

 forms resinous masses. It is best to allow the mixture to stand 

 for a day or two, to obtain the glancing needles which constitute 

 Plattner's Crystallised Bile. 



Scheme for Bile-Salts , etc, 



200 cc. of ox-bile, dried, mixed with animal charcoal, are extracted with 

 absolute alcohol by the aid of heat ; filter. 



Residue, rmicin, Alcoholic solution treated with 



pigments, salts, charcoaL ether. 



Precipitate, Solution contains 



Bile-salts. Cholesteriv. 



