404 PHYSIOLOGICAL CHEMISTRY 



therefore, which occurs in the urine as indoxyl potassium sulphate or 

 indican, 



CH 



HC C C(O.S0 3 K), 



I II II 

 HC C CH 



\/\/ 

 CH NH 



is clinically the most important of the ethereal sulphuric acids. Under 

 normal conditions from 4 to 20 mg. of indican are excreted per day. 

 The variations are due mainly to diet, a high meat diet causing an 

 increase and a carbohydrate diet a decrease. Pathologically the great- 

 est increases are found in disorders involving increased putrefaction and 

 stagnation of intestinal contents. Bacterial decomposition of body 

 protein as in gangrene, putrid pus formation, etc., gives rise to an 

 increased indican excretion. 



It was formerly believed 'that the phenol was excreted practically 

 quantitatively in the conjugated form. Researches of Folin and Denis 1 

 seem to indicate that this is not true. Only part of the phenols formed 

 in intestinal putrefaction are excreted in the conjugated form, the 

 remainder being excreted as free phenol. The phenol output tends to 

 vary directly but not proportionally with the protein ingestion. The 

 total phenol excretion of normal men on an ordinary mixed diet aver- 

 ages around 0.4 gram per day. 



TESTS FOR INDICAN 2 



i. Jaffe's Test Nearly fill a test-tube with a mixture composed of equal 

 volumes of concentrated HC1 and the urine under examination. Add 2-3 c.c. 

 of chloroform and a few drops of a calcium hypochlorite solution, place the thumb 

 over the end of the test-tube and shake the tube and contents thoroughly. The 

 chloroform is colored more or less, according to the amount of indican present. 

 Ordinarily a blue color due to the formation of indigo-blue is produced; less 

 frequently a red color due to indigo-red may be noted. 



Repeat this test on some of this same urine to which formaldehyde has 

 been added. Is there any variation in the reaction from what you previously 

 obtained ? 



The following represents the reaction (see also pages 2 1 5-2 1 6) : 



1 Folin and Denis: Jour. Biol. Chem., 22, 309, 1915. 



* The urine should always be examined fresh if this is possible. In any event formalde- 

 hyde should never be used as a preservative for such urines as are to be examined for indican 

 by means of any test involving hypochlorite or potassium permanganate. The formalde- 

 hyde through its reducing power lowers the oxidizing efficiency of the mixture. The forma- 

 tion of formic acid from the aldehyde may also interfere. 



