HYPOXANTHINE OR SAKKINE. 131 



3. Prepare from urine thus : Evaporate it to a 

 syrup, add some hydrochloric acid, and shake in a 

 stoppered bottle with its own volume of ether ; allow 

 to stand one hour, then add $ of its volume of 

 alcohol ; allow to stand a short time ; remove the upper 

 ethereal layer with a syphon. Shake this ethereal 

 extract with a small quantity of water ; allow to stand ; 

 remove the ethereal layer as before and evaporate. 

 The hippuric acid will be obtained in crystals usually 

 of a yellowish-brown colour. This colour can be re- 

 moved by treatment with animal charcoal. 



4. Recrystallise the acid from boiling water, in which 

 it is easily soluble. Observe its slight solubility in cold 

 water, and easy solubility in alcohol. 



5. Melt it in a glass tube and let it consolidate by 

 cooling. Then heat again to fusion and dry distillation . 

 Observe the irritating vapours of benzoic acid, and a 

 sublimate of the same, and a charcoal left in the bottom 

 of the tube. 



6. Boil hippuric acid for half an hour with hydro- 

 chloric acid. It will be split up into glykokoll and 

 benzoic acid. Separate both as described under 

 glykokoll. 



7. To a solution of neutral hippurate add solution of 

 ferric chloride. A cinnamon- coloured precipitate of 

 ferric hippurate will be formed. 



Hypoxanthine or Sarlwne, C 5 H 4 N 4 0. 1. The mother 

 liquor of xanthine hydrochlorate, obtained as under 

 Xanthine, is evaporated, and another crop of crystals 

 removed (sarkine salt containing xanthine). The 



