ACETOACETIC ACID. 777 



alcohol, and ether in all proportions. On heating to boiling with water, 

 and especially with acids, it decomposes into carbon dioxide and ace- 

 tone, and therefore gives the above-mentioned reactions for acetone. 

 It differs from acetone in that it gives a violet-red or brownish-red 

 color with a dilute ferric-chloride solution. For the detection of this 

 acid we make use of the following reactions which may be applied directly 

 to the urine: 



GERHARDT'S Reaction. Treat 10-15 cc. of the urine with ferric- 

 chloride solution until it fails to give a precipitate, filter, and add some 

 more ferric chloride. In the presence of acetoacetic acid a wine-red 

 color is obtained. The color becomes paler at the room temperature 

 within twenty-four hours, but more quickly on boiling (differing from 

 salicylic acid, phenol, sulphocyanides) . A portion of the urine slightly 

 acidified and boiled does not give this reaction on account of the decom- 

 position of the acetoacetic acid. 



ARNOLD and LIPLIAWSKY'S Reaction. 6 cc. of a solution contain- 

 ing 1 gram of p-aminoacetophenone and 2 cc. of concentrated hydro- 

 chloric acid in 100 cc. of water are mixed with 3 cc. of a 1-per cent potas- 

 sium-nitrite solution and then treated with an equal volume of urine. 

 A few drops of concentrated ammonia are now added and violently 

 shaken. A brick-red coloration is obtained . Then take 10 drops to 

 2 cc. of this mixture (according to the quantity of acetoacetic acid in 

 the urine), add 15-20 cc. HC1 of sp.gr. 1.19, 3 cc. of chloroform, and 

 2-4 drops of ferric-chloride solution and mix without shaking. In the 

 presence of acetoacetic acid the chloroform is colored violet or blue 

 (otherwise only yellowish or faintly red). This reaction is more delicate 

 than the preceding test and reacts with 0.0 1 p.m. acetoacetic acid. Large 

 amounts of acetone (but not the quantity occurring in urines) give this 

 reaction according to ALLARD. 1 



BONDI and ScnwARz's 2 Reaction. 5 cc. of the urine is treated drop 

 by drop with iodine-potassium iodide solution until the color is orange- 

 red. Then warm gently and when the orange-red color has disappeared 

 add the iodine solution again until the color remains permanent on 

 warming. Then boil, when the irritating vapors of iodo-acetone will 

 attack the eyes. Acetone does not give this reaction. 



Detection of Acetone and Acetoacetic Acid in the Urine. Before test- 

 ing for acetone test for acetoacetic acid; as this acid gradually decom- 

 poses on allowing the urine to stand, the specimen must be as fresh as 

 possible. In the presence of acetoacetic acid the urine gives the above- 

 mentioned tests. In testing for acetone in the presence of acetoacetic 



1 Arnold, Wicn. klin. Wochenschr., 1899, and Centralbl. f. innere Mod., 1900; 

 Lipliawsky, Deutsch. med. Wochenschr., 1901; Allard, Berl. klin. Wochenschr., 1901. 



2 Wien. klin. Wochenschr., 1906. 



