48 BILE. 



3. Prepare a solution of syntonin ( iii, 4) by digesting albumin in water 

 containing O'2 per cent, of hydrochloric acid. On the addition of a drop of 

 bile, the mixture curdles en masse. If a large quantity of bile be added, 

 little or no precipitate may be formed, the liquid being rendered alkaline. 



4. Boil bile with twice its bulk of strong hydrochloric acid for five minutes. 

 The bile is decomposed into bile-resin (cholic acid with colouring matter) 

 and glycin and taurin, the two last-mentioned substances remaining in 

 solution. 



5- Pettenkofer's Test for CholiC acid. Spread a drop of bile 

 in a thin film on a white porcelain capsule. Mix with a drop of strong 

 solution of cane-sugar. Add concentrated sulphuric acid drop by drop, and, 

 if necessary, warm. A deep purplish-red colour appears. 



6. Repeat the test with an alcoholic solution of bilin. The same colour 

 is produced. 



7- Gmelin's Test for the colouring matter. Spread a drop of 



bile in a thin film on a white porcelain capsule. Allow a drop of strong 

 nitric acid to fall into the middle of the film and observe the effect. The 

 drop becomes surrounded by rings of green, blue, red, and yellow, in the 

 order in which they have been named. Consequently the green, which is first 

 formed, is eventually farthest from the drop of acid. If, instead of allowing 

 the liquid to remain undisturbed, the acid be mixed with the bile, the liquid 

 passes through the same tints in the same order. 



8. Warm a little nitric acid in a test-tube. Incline the tube and pour bile 

 down the side, so as to form a layer over the acid. The colours appear as in 

 7, at the line of contact of the two liquids. 



9- Cholesterhl. Extract gall-stones with ether. The extract yields, 

 on evaporation, crystals of cholesterin, which, when dropped into warm 

 sulphuric acid, dissolve with a red colour. The residue, insoluble in ether, 

 consists of colouring matter and mucin. 



10. Acidify 10 c.c. of bile in a flask with hydrochloric acid and add zinc. 

 Nearly close the flask with a cork to which acetate of lead paper is attached. 

 The taurin of the bile is decomposed, H 2 S being formed, which blackens the 

 lead paper. 



Vll. Urine. 



1. Observe reaction and colour. 



2. Determine the specific gravity, either by weighing or with the urine- 

 meter. Observe the effect of temperature. 



3. Compare fresh with stale urine as regards appearance, smell, and re- 

 action. 



4. Sulphates. Add baric chloride after acidifying with hydrochloric 

 acid. A white precipitate of baric sulphate is formed. 



5- Chlorides. Add argentic nitrate after acidifying with nitric acid. A 

 white curdy precipitate of argentic chloride is produced. 



6. Phosphates. Add ammonic molybdate to urine which has been 

 mixed with half its volume of nitric acid. Boil. A yellow crystalline pre- 

 cipitate falls. 



