496 DIGESTION. 



Fallacies to be avoided in using Gmelin's Test. This test 

 must never be applied to a fluid containing alcohol, as the 

 alcohol alone will cause abundant formation of nitrous acid, 

 and produce the colored rings, although no bile pigment is 

 present. 



In using it for the detection of bile pigment in urine, the 

 presence of indican may lead to error. This is avoided if care 

 is taken to observe ttvr-.t the green, violet, and red zones are all 

 present, as urine cojH^ing much indican may exhibit green 

 and yellow zones alone, or green and yellow with blue between, 

 but never exhibit all of the colors in the right order. 



* 136. Bilirubin. C, 6 H 1H N 2 O r Synonymes : Bilifulvin, 

 Biliphain, Cholepyrrhin, Haematoidin. 



Preparation from Bile. Put some fresh dog's. bile in a 

 small flask, acidulate it with acetic acid, add chloroform till 

 the flask is almost full, warm it in a water-bath, and shake. 

 The chloroform takes up the bilirubin and settles at the bot- 

 tom of the flask. Remove it with a pipette, and evaporate it 

 quickly. The red residue is bilirubin. Add alcohol to it to 

 dissolve out the impurities ; pour it off after it has stood some 

 time ; dissolve the bilirubin again in chloroform, and again 

 evaporate. To obtain it pure, this may be repeated once or 

 twice. When crystallized, it is of a red color. During crys- 

 tallization, a part of it is apt to become oxidized with biliver- 

 din, on which account it is easier to obtain it pure by precipi- 

 tating it from the choloroform solution by the addition of 

 alcohol. The precipitate is amorphous, and of an orange 

 color. 



The amount of bilirubin which can be obtained from the 

 bile of a single dog is very small. To obtain it in greater 

 quantities, biliary calculi may be used. 



I' reparation of Bilirubin from Gall Stones. Reduce the 

 gall stone to powder, and extract it first with ether, to free it 

 irom fiit and cholesterin, so long as any of the powder is dis- 

 solved ; next boil it with water, to free it from admixture of 

 bile ; and lastly, treat it with dilute hydrochloric acid, to 

 remove lime and magnesia. Dissolve the residue in warm 

 chloroform. Filter (preserving the undissolved part), distil, 

 or evaporate off the chloroform ; extract the residue with abso- 

 lute alcohol (preserving the alcoholic extract, see 147), and 

 then with ether. Dissolve the residue in a second quantity of 

 chloroform, and evaporate until the bilirubin begins to sepa- 

 rate, and then precipitate it with alcohol. 



Properties of Bilirubin The orange-colored precipitate is, 

 1, quite insoluble in water; 2, very slightly soluble in ether; 

 :i, springly soluble in alcohol, but rather more soluble than in. 

 ether ; 4, soluble in chloroform, especially when warm, and in 

 a less degree in benzol and bisulphide of carbon, amyl-alco- 



