7 76 URINE. 



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. 



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 1 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 

 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. 



LA v. BITTO'S 2 reaction is based on the fact that on adding a solution of 

 metadinitrobenzene, made alkaline with caustic potash, to acetone, a violet-red 

 color is produced which becomes cherry-red on acidifying with an organic acid or 

 metaphosphorie acid. Aldehyde gives a similar violet-red color which becomes 

 yellowish-red on acidification. Creatinine does not give this reaction. FROM- 

 MER 3 has suggested the following method for detecting acetone: Treat 10 cc. 

 of the urine with 1 gram potassium hydroxide and add 10-20 drops of an alkaline 

 solution of salicyl-aldehyde. On warming a purple-red coloration is obtained in 

 the presence of acetone. 



Acetoacetic acid, C 4 H 6 O 3 , acetylacetic acid, diacetic acid, CH 3 .CO. 

 CH 2 .COOH, is a colorless, strongly acid liquid which mixes with water, 



1 Journ. of Physiol., 37. 



2 Annal. d. Chem. u. Pharm., 269. 



3 Berlin, klin. Wochenschr.. 1905. 



