EXAMINATION OF THE URINE. 117 



cipitate in water and dissolve by adding sodium hydroxide 

 solution, etc. If a centrifuge is not available the precipitate 

 may be washed with alcohol on the filter. 



3. A larger amount of primary albumoses (0.3 g. com- 

 mercial peptone to 100 cc. of urine) may be detected as fol- 

 lows: Acidify the urine with acetic acid to distinctly acid 

 reaction and add an equal volume of concentrated salt solu- 

 tion: turbidity, which clears up on heating and returns on 

 cooling. 



XVI. GLUCOSE, C 6 H 12 6 . 



Also called grape-sugar, diabetic sugar, and dextrose, 

 easily soluble in water and dilute alcohol, difficultly in abso- 

 lute alcohol. Melting-point of the anhydrous glucose 1 146. 

 The solution of glucose is dextrorotatory. 



1. A small portion is cautiously heated in a dry test-tube. 

 The glucose melts and turns yellow; when heated more 

 strongly the melted mass turns dark brown and develops a 

 peculiar odor so-called caramel odor. After cooling dis- 

 solve the residue in water: deep-brown solution (caramel 



color used in confectionery). 



2. Place a small quantity of glucose and a piece of caustic 

 potash in a test-tube, add a few drops of water, and heat: 

 vigorous reaction and a brown coloration. When perfectly 

 cold acidify cautiously with dilute sulphuric acid : odor of 

 caramel. 



3. Trommer's test; 4. Bismuth test; 5. Potassium fer- 

 rocyanide test; 6. Silver test; 7. Indigo test; 8. Rubner's 

 test; and 9. Fermentation test. See under Milk-sugar, 

 page 11. For all these reactions use two solutions A and B, 

 A containing 4 g. of glucose dissolved in 200 cc. of water, i.e., 



1 Glucose also crystallizes with one molecule of water of crystalliza- 

 vfeion: C 6 H 12 6 +H 2 0. 



