284 THE URINE. 



Quantitative Estimation. The quantitative estimation of acetone 

 is best conducted according to the method of Messinger, as modified 

 by Huppert. It is based upon the principle underlying Lieben's 

 test, viz., the formation of iodoform when a dilute solution of iodo- 

 potassic iodide is added to an alkaline solution of acetone. By 

 determining the amount of iodine which is consumed in this reac- 

 tion the corresponding amount of acetone can then be calculated. 



One hundred c.c. of urine, or less if much acetone is present, as 

 determined by LegaPs test applied directly to the urine, are treated 

 with 2 c.c. of a 50 per cent, solution of acetic acid and distilled 

 until all the acetone has passed over. The distillate is received in 

 a bulb-tube containing water. The solution which thus results is 

 treated with 1 c.c. of a 12 per cent, solution of sulphuric acid and 

 redistilled. The second distillate is free from phenols. To it a 

 carefully measured quantity of a one-tenth normal solution of iodine 

 is added (10 c.c. for every 100 c.c. of urine), together with a 50 

 per cent, solution of sodium hydrate, until the iodoform separates 

 out. After shaking, the mixture is set aside for a few minutes, and 

 then acidified with concentrated hydrochloric acid. If iodine is 

 present in excess, a brown color thus develops. This excess is then 

 titrated with a decinormal solution of sodium thiosulphate, using 

 starch solution as a final indicator. The number of cubic centim- 

 eters emyloyed in this titration is deducted from the amount of 

 the iodine solution added. The difference multiplied by 0.967 then 

 indicates the amount of acetone in the 100 c.c. of urine, in milli- 

 grammes. 



Lactic Acid. 



Normally lactic acid is not found in the urine. It is met with in 

 various diseases of the liver which are associated with an extensive 

 destruction of the hepatic parenchyma, as also in conditions in which 

 the oxidation-processes of the body are impaired in general. It is 

 notably seen in acute yellow atrophy, in poisoning with phosphorus 

 and carbon monoxide, in long-continued anaemic conditions, etc. 

 Smaller amounts have been found in soldiers after marches and in 

 epileptic patients after severe seizures. 



Isolation. To isolate the substance from the urine the following 

 method may be employed, as suggested by Araki : 



The collected urine of twenty-four hours is evaporated to 

 about 50 or 60 c.c., treated with ten times as much of 95 per cent, 

 alcohol, and set aside for twelve hours. It is then filtered and freed 

 from the alcohol by distillation. The residual fluid is acidified with 

 phosphoric acid, and repeatedly extracted with five times its volume 

 of ether. The ethereal extract is evaporated and the remaining 

 yellow syrup dissolved in a little water. Any hippuric acid which 

 may be present thus separates out and is filtered off. The filtrate is 

 now treated with pure lead carbonate in substance, heated on a 

 water-bath for thirty minutes, and filtered on cooling. From the 



