ACETONE. 823 



which in diabetes gives a pomaceous or fruit odor to the urine as well as 

 the expired air. It is lighter than water, with which it mixes in all 

 proportions, also with alcohol and ether. The most important, reactions 

 for acetone are the following: 



LIEBEN'S lodoform Test. When a watery solution of acetone is treated 

 with alkali and then with some iodo-potassium-iodide solution and gently 

 warmed, a yellow precipitate of iodoform is produced, which is known 

 by its odor and by the appearance of the crystals (six-sided plates or stars) 

 under the microscope. This reaction is very delicate, but it is not char- 

 acteristic of acetone. GUNNING'S modification of the iodoform test con- 

 sists in using an alcoholic solution of iodine and ammonia instead of the 

 iodine dissolved in potassium iodide and alkali hydroxide. In this case, 

 besides iodoform, a black precipitate of nitrogen iodide is formed, but 

 this gradually disappears on standing, leaving the iodoform visible. This 

 modification has the advantage that it does not give any iodoform with 

 alcohol or aldehyde. On the other hand, it is not quite so delicate, 

 but still it detects 0.01 milligram of acetone in 1 cc. 



FROMMER'S 1 Test. This reagent is a 10 per cent alcoholic solution 

 of salicylaldehyde. Add 1-2 cc. of this solution to 10 cc. of the solution 

 (urine) and add to this mixture 1 gram KOH in substance, when a 

 carmine-red color will be observed. If necessary warm to about 70 C. 

 This reaction is just as delicate as the above. 



REYNOLD'S Mercuric-oxide Test is based on the power of acetone to 

 dissolve freshly precipitated HgO. A mercuric-chloride solution is pre- 

 cipitated by alcoholic caustic potash. To this add the liquid to be 

 tested, shake well, and filter. In the presence of acetone the filtrate 

 contains mercury, which may be detected by ammonium sulphide. 

 This test has about the same delicacy as GUNNING'S test. Aldehydes 

 also dissolve appreciable quantities of mercuric oxide. 



LEGAL'S Sodium Nitroprusside Test. If an acetone solution is treated 

 with a few drops of a freshly prepared sodium-nitroprusside solution 

 and then with caustic-potash or soda solution, the liquid is colored ruby- 

 red. Creatinine gives the same color; but if the mixture is saturated 

 with acetic acid, the color becomes carmine or purplish red in the presence 

 of acetone, but yellow and then gradually green and blue in the presence 

 of creatinine. With this test paracresol responds with a reddish-yellow 

 color, which becomes light pink when acidified with acetic acid and can- 

 not be mistaken for acetone. ROTHERA 2 has suggested a modification 

 which is more delicate by using ammonium salts and ammonia. 



PENZOLDT'S Indigo Test depends on the fact that orthonitrobenzaldehyde 

 in alkaline solution with acetone yields indigo. A warm saturated and 



1 Berl. klin. Wochenschr., 1905. 2 Journ. of Physiol., 37. 



