400 



Dr. C. A. MacMunn. 



near D was absorbed, in a thinner layer three other bands were 

 visible, the colour of the solution changing to a fine carmine-red. The 

 three bands read as follows : — 



1st Band \558— 534 



2nd „ X516— 496 



3rd „ X476— 462 (see sp. 20 and 21) 



On boiling this solution the colour was not destroyed, but the 

 band in violet disappeared. When agitated with chloroform or ether 

 no pigment went into solution. When the red liquid got by adding 

 hydrochloric acid to the urine was treated with caustic potash in 

 excess the colour disappeared, but again reappeared on adding hydro- 

 chloric acid in excess. 



But in the second specimen obtained three weeks after the above 

 examination, from the same patient, the chemical and spectroscopic 

 characters differed slightly from those of the first specimen, but were 

 essentially the same. On adding about one quarter of its own 

 volume of nitric acid the liquid assumed a splendid red colour, and 

 when agitated with chloroform, the latter removed the colouring-matter 

 forming a lake-red solution; by means of daylight the spectrum was 

 seen to consist of one broad band across the middle of the spectrum, 

 from near D to half way between F and G, and on dilution this band 

 could not be divided into two. After evaporation of this solution a pale 

 yellow residue was left, the change of colour being due probably to 

 the action of the heat, and a little of the acid left in the chloroform, 

 on the pigment. If too much nitric acid was added it also lost its 

 red colour. With nitric acid alone, a band could be seen between D 

 and E and touching the latter line. 



On treating the urine with hydrochloric acid and shaking with 

 chloroform, the latter assumed a fine carmine colour, and after filter- 

 ing gave the same kind of absorption as the nitric acid treated 

 liquid, the broad band extending from between D and E to beyond 

 F. Ammonia at once discharged the red colour of this solution, but 

 it reappeared on acidifying afresh ; caustic potash and caustic soda 

 acted similarly. On adding alcohol to a chloroformic solution the 

 colour changed to orange, and then only the violet end of the 

 spectrum was absorbed. 



The red colour produced by nitric acid, or hydrochloric acid, was 

 also taken up by agitating with bisulphide of carbon, and this gave 

 the same kind of spectrum as the chloroform solution. 



It was interesting to find out whether indican was here present ; 

 the urine was therefore boiled with hydrochloric acid, and after 

 cooling shaken with chloroform, it then gave the indigo-blue band 

 before D, and another band after D ; and on evaporation left a bluish- 

 black residue. A portion of the latter was soluble in alcohol, forming 



