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Dr. C. A. MaoMunn. Researches into the [Dec. 16, 



III. " Further Researches into the Colouring-matters of Human 

 Urine, with an Account of their Artificial Production from 

 Bilirubin, and from Haematin." By Charles A. MacMunn, 

 B.A., M.D. Communicated by Dr. Michael Foster, Pre- 

 lector of Physiology in Trinity College, Cambridge. Re- 

 ceived November 10, 1880. 



In a former paper which I had the honour of laying before the 

 Royal Society, I endeavoured to describe the spectroscopic and some 

 of the chemical characters of febrile urobilin. 



In the present paper I have given the results of further spectro- 

 scopical research, which had for its object: — (1.) To determine the 

 differences which might exist between those urinary pigments which 

 are recognisable by means of the spectroscope, in health and disease. 

 (2.) The isolation of normal urinary pigment, giving the band at F. 

 (3.) To attempt to trace back to their source all these pigments. 

 (4.) To examine bile more carefully for the presence of urobilin. 

 (5.) To find an explanation of the absorption-bands noticed in the bile 

 of certain animals. 



In this paper I shall give principally the spectroscopic appearances 

 of these pigments, reserving for a future communication a full de- 

 scription of their chemical characters. Speculation will be avoided as 

 much as possible, and a plain statement of the facts which presented 

 themselves will be adhered to, which show that there is irresistible 

 evidence of the relationship between the colouring-matters of blood, 

 bile, and urine. 



It is probable that a knowledge of how the urinary pigments can 

 be prepared artificially will be of great use in enabling us to under- 

 stand how they are produced in the body. Thus, the knowledge of 

 the fact that the spectrum of urobilin varies according to the amount 

 and the kind of oxidation, or reduction, or both, to which it has been 

 subjected in the body, which I shall endeavour to show is the case, is 

 of great importance, especially as we can produce in the laboratory 

 pigments (from bile- and blood-colouring matter), by a greater or a 

 less amount of oxidation or reduction, or of both combined, which can 

 be made to resemble exactly pigments obtained from urine in health 

 and disease. 



The Spectrum of Normal Urine : Its Band due to the presence of a 

 Pigment indistinguishable from Gholetelin. — In examining urine obtained 

 from individuals in a healthy condition, I always can see a band at F, 

 and when a layer sufficiently deep to show this band is treated with 

 caustic soda, caustic potash, or ammonia, the band can be no longer 

 seen. On the subsequent addition of an acid, it is again brought into 

 view. But if the urine be obtained from a febrile case, or indeed, 



