28O PHYSIOLOGICAL CHEMISTRY. 



CH 



//\ 

 HC C-C(0-S0 3 H), 



Hi fl JJH 



\/\/ 



CH NH 



therefore, which occurs in the urine as indoxyl potassium sulphate 

 or indican, 



CH 



HC C-C(OSO 3 K), 



I! 



\/\/ 



CH NH 



is clinically the most important of the ethereal sulphuric acids. 



TESTS FOR INDICAN. 



i. Jaffa's Test. Nearly fill a test-tube with a mixture composed 

 of equal volumes of concentrated HC1 and the urine under exam- 

 ination. 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. 



This is the reaction (see also pages 162 and 163) : 



CH 



HC C-C-OH 



2 | || || +20 = 

 HC C CH 



\/\/ 

 CH NH 



Indoxyl, C 8 H 7 NO. 



CH CH 



//\ /\ 



HC C-C-0 0-C-C CH 



I I II I II I +2H 2 



HC C C- - C C CH 



\/ \/ \/ \/ 



CH NH NH CH 



Indigo-blue, Ci 6 H 10 N 2 O 2 . 



