398 



Dr. C. A. MacMunn. 



neither view is qnite correct. The reddening produced by boiling with 

 hydrochloric acid in normal urine is certainly not due to the oxidation 

 of indican, since I can detect no indigo-blue under these circumstances, 

 but it is partly due to the oxidation of the chromogen of urobilin, 

 since the latter goes into the chloroform when the mixture is shaken 

 with it, and can be detected by means of the spectroscope. At the 

 same time the oxidation of the urobilin chromogen does not account 

 for all the red coloration produced in normal urine and for the 

 presence of the colouring matter, which then possesses an absorptive 

 power for the violet end of the spectrum. Hence the so-called 

 "indigo-red" in urine is not due to the presence of indican, as it is 

 present in quite normal urine, while indigo-blue cannot be obtained 

 from the same urine in all cases. I have, therefore, to agree with those 

 who maintain that the above- described absorption of the violet end of 

 the spectrum is due to "urrhodin," and who also maintain that 

 urrhodin and indigo-red are different colouring-matters. 



In most cases where I have detected indican by this method I have 

 noticed a band in the urine which seems to be connected in some way 

 with its presence. Thus, in the urine of a case of aphasia, due to 

 embolism from mitral disease, the addition of hydrochloric acid to 

 the urine (which was a reddish colour) made it redder in colour, and 

 a band became developed, beginning about half way between D 

 and E, and extending nearly to E. It probably extended from 

 \558 — 534. The urobilin band was also visible. On boiling the 

 urine with hydrochloric acid, cooling, and agitating with chloroform, 

 the latter became a faint purple-red colour ; this showed two bands 

 with their centres at \608 and \571'5. On evaporating the chloro- 

 form, alcohol took up the pigment from the residue, and gave two 

 similar bands. In this case the band before D was less shaded than 

 that after D, but in other cases the reverse was the case ; this teaches 

 that not one, but two distinct colouring -matters are indicated by the 

 presence of these bands, for if only one colouring-matter was indi- 

 cated by them then they should possess the same relative degree of 

 shading when dissolved in the same medium in different cases. Another 

 specimen of urine gave* the band referred to above, namely, extend- 

 ing from half-way between D and E to near E, and on treating, as 

 before, with hydrochloric acid and chloroform, the indigo-blue band 

 before D was well seen, the band after D uncertain. The urobilin 

 band was also visible. In a specimen of urine (from a case of 

 enteiitis), which was a kind of olive-brown colour, the same treat- 

 ment developed the bands, of which one extended from \620 — 592, 

 the other \583— 561 (in a chloroformic solution). Possibly a bile 

 pigment partially oxidised might be mistaken for the pigment, but in 



Without any treatment whatever. 



