120 PHYSIOLOGICAL AND PATHOLOGICAL CHEMISTRY. 



XVII. EXAMINATION OF DIABETIC URINE FOR ACETO ACETIC 

 ACID, CH 3 COCH 2 COOH. 



1. Add directly to some of the urine ferric chloride solu- 

 tion. The quantity of this should not be too small, since the 

 iron chloride is at first used up to form ferric phosphate (gray 

 precipitate): a red coloration indicates the presence of 

 acetoacetic acid. 



2. Acidify the urine (about 50 cc., sometimes even 10 cc. 

 is sufficient) with dilute sulphuric acid, shake with an equal 

 volume of ether, separate the ether and agitate it with a very 

 little dilute ferric chloride solution. In the presence of 

 acetoacetic acid the aqueous layer turns violet-red. After 

 the use of salicylic acid the urine gives a very similar reaction. 



XVIII. ACETONE, CH 3 COCH 3 . 



Clear colorless fluid with an agreeable odor, miscible in 

 every proportion with water, alcohol, and ether, boiling-point 

 56 to 57. To 250 cc. of urine add a few drops of acetone 

 and some hydrochloric acid, distil off about 50 cc., and make 

 the following tests with the distillate : 



1. The lodoform Test. Add a few drops of sodium 

 hydroxide solution, then iodine potassium iodide solution. 

 The fluid at once becomes turbid and gives the odor of iodo- 

 form (CHI 3 ). On standing iodoform is deposited. Examine 

 under the microscope. Aldehyde also gives the same reac- 

 tion. The use of ammonia instead of sodium hydroxide is 

 said to exclude this confusion (black nitrogen iodide is formed 

 at first in this case, but gradually disappears) : this test, how- 

 ever, is less delicate. 



2. Legal's Test. Add to some of the distillate enough 

 sodium nitroprusside solution (freshly prepared) to distinctly 

 color the fluid and then some sodium hydroxide solution: 

 the fluid turns ruby-red. If acidified with acetic acid the 



