824 URINE. 



then cooled solution of the aldehyde is treated with the liquid to be tested 

 for acetone and next with caustic soda. In the presence of acetone the 

 liquid first becomes yellow, then green, and lastly indigo separates; and 

 this may be dissolved with a blue color by shaking with chloroform; 

 1.6 milligrams acetone can be detected by this test. 



Acetoacetic Acid, C^eOs, acetylacetic acid, diacetic acid, CHs.CO. 

 CH2.COOH, is a colorless, strongly acid liquid which mixes with water, 

 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 cooling, on account 

 of the decomposition 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. H<C1 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 0.04 p.m. acetoacetic acid. Large 

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

 reaction according to ALLARD.* 



BONDI and SCHWARZ'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 irritat- 

 ing vapors of iodo-acetone will attack the eyes. Acetone does not give this reaction. 



1 Arnold, Wien. klin. Wochenschr., 1899, and Centralbl. f. innere Med., 1900; 

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



2 Wien. klin. Wochenschr., 1906. 



