50 HANDBOOK FOR BIO-CHEMICAL LABORATORY. 



Properties. Pure uric acid is a white, odorless, and taste- 

 less powder consisting of very small rhombical prisms or 

 plates. It is insoluble in alcohol and ether, rather easily sol- 

 uble in boiling glycerin, very difficultly soluble in cold water 

 (14000-15000 parts), and difficultly soluble in boiling water 

 (1800-1900 parts). It is soluble in sulphuric acid in the cold 

 without decomposition, and readily soluble in many salts of 

 the alkalies, as in the caustic alkalies; ammonia, however, 

 scarcely dissolves it. Uric acid reduces alkaline solutions of 

 copper or silver, but not alkaline solutions of bismuth. 



Hippuric Acid, 



C 9 H 9 NO, or C 6 H 5 .CO.NH.CH a .COOH. 



Preparation. 1. Treat fresh horse or cow urine with milk 

 of lime until it is of a strong alkaline reaction; warm, filter, 

 evaporate the filtrate to a syrupy consistency, and acidify 

 strongly with HC1 when cold. The hippuric acid thus pre- 

 cipitated is drained, washed with cold water, pressed between 

 filter-paper, dissolved in as small a quantity of boiling water 

 as possible, filtered, and the boiling-hot filtrate treated with 

 chlorine gas until the color of the solution is pale yellow. 

 Cool quickly, filter, wash the hippuric acid a few times with 

 cold water, and crystallize from boiling water after treating 

 the solution with animal charcoal. (Tfi. Curtius.) 



2. One litre of the fresh horse or cow urine is made faintly 

 alkaline with sodium carbonate and filtered, the filtrate 

 evaporated nearly to dryness, and the residue repeatedly ex- 

 tracted with cold, strong alcohol. The alcohol is nearly en- 

 tirely distilled off from the extracts the remaining watery 

 solution acidified with HC1, and then repeatedly extracted 

 with fresh portions of acetic ether (at least five times). The 

 acetic ether extracts are united, and washed by shaking with 

 water in a separatory funnel, and then evaporated at a moderate 

 temperature. The residue is repeatedly treated with petro- 



