28 HANDBOOK FOB BIO-CHEMICAL LABORATORY. 



Properties. Taurin crystallizes in colorless, often large, 

 shining, 4-6-sided prisms, which dissolve in 15-16 parts water 

 at the ordinary temperature, but rather more readily in warm 

 water. It is insoluble in alcohol arid ether. Taurin is taste- 

 less and its solutions are neutral to test-paper. On boiling 

 with strong caustic alkalies it yields acetic acid and sul- 

 phurous acid but no alkali sulphides; but this decomposition 

 does not occur on boiling with HC1 or HM) 3 . Taurin com- 

 bines with metallic oxides such as mercuric oxide. Metallic 

 salts do not precipitate solutions of taurin. 



BiliruMn, C,.H 18 N,0 S or C a ,H 3e N,0,. 



Preparation. 1. Finely-powdered gallstones (of oxen) are 

 first extracted with ether and then with boiling water to remove 

 cholesterin and bile-acids. The residue is treated with dilute 

 hydrochloric acid, which sets the pigment free. The insoluble 

 powder is thoroughly washed with water and alcohol and then 

 dried and boiled with chloroform until entirely extracted. 

 Evaporate the chloroform solution on the water-bath and treat 

 the powdered residue with absolute alcohol and ether, which 

 removes the Ulifuscin. Dissolve the remaining residue, insolu- 

 ble in alcohol, in chloroform; precipitate the bilirubin from 

 this solution by the addition of alcohol, and repeat this several 

 times. The bilirubin is finally dissolved in chloroform and 

 allowed to evaporate spontaneously, when crystals of bilirubin 

 separate. 



2. Dilute bile (preferably from the dog) with water, and 

 precipitate with milk of lime. Pass carbon dioxide through 

 the mixture, filter and wash. Suspend the precipitate in water, 

 decompose it with hydrochloric acid and shake with chloro- 

 form, care being taken to avoid an excess of air. The chloroform 

 solution is evaporated to a very small volume, precipitated by 

 alcohol, and purified by repeated solution in chloroform and 

 reprecipitating with alcohol. 



