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



If this hasmatoin is then dissolved in alcohol and diluted with 

 water, the solution put into a narrow and deep beaker (or better 

 in a flask), a piece of sodium amalgam added, and the whole gently 

 heated on the water-bath, a change will be found to have taken 

 place after some time. The colour gets much lighter, becoming at 

 last yellow, and it then gives sp. 12, Chart III ; this is seen to be 

 the spectrum of urohasmatin prepared by the former method and 

 treated in alcoholic solution with caustic soda. The fluid may 

 then be filtered, the filtrate treated with sulphuric acid to acidity, 

 when its yellow colour changes to orange-red. It is then (after acidi- 

 fication) filtered, put into a separating funnel and shaken with 

 chloroform ; this chloroformic solution is reddish and gives sp. 14, 

 Chart III.* When the chloroform is distilled off a dark-brown pig- 

 ment is left, which alcohol dissolves, forming a red fluid giving sp. 11, 

 Chart III. Treated with caustic soda it gets orange (i.e., less red) 

 and gives sp. 12, Chart III. Ammonia produced the same effect, 

 and its behaviour with other reagents shows that this is the same 

 pigment as that obtained by the action of zinc and sulphuric acid on 

 ha3matoin. 



It is, therefore, certain that by the action of reducing agents on 

 hsematoin a pigment can be prepared, identical with a pigment which 

 can be obtained from urine in certain diseased conditions, and the 

 name uroha3matin best expresses the origin of that pigment. 



Artificial production of a Pigment from Acid Hcematin by Oxidation, 

 indistinguishable from Choletelin and from Normal Urobilin. — The 

 identity of ch oletelin and urobilin of health has already been proved 

 in this paper. I have now to describe a method by means of which 

 a pigment, which cannot be distinguished from either, can be procured 

 from acid ha3matin (hsematoin). So far as I know, this experiment 

 has never been described. 



A solution of acid heematin having been prepared as before, it is 

 treated with peroxide of hydrogen until it changes colour. The red 

 colour first seems to get slightly darker, but it soon changes to brown- 

 yellow ; and then a curious change is seen to have taken place in the 

 spectrum. All the bands of acid heematin have gone, and instead, a 

 band /3, or 7, is seen between green and blue (sp. 15. Chart III), wave- 

 length 507 to 484. 



This change can be produced by treating the hsematoin in the 

 original acid solution, or when separated in the neutral state by means 

 of chloroform, with the peroxide ; but if the latter method be adopted 

 we must slightly acidulate again before the pigment can be isolated. 

 The former method is, of course, the easier. If this solution of 

 peroxidised acid hsematin be put into a funnel and shaken with chlo- 

 roform, the latter becomes reddish-yellow, and when separated and 



* Under certain unknown conditions another feeble band in red may be noticed. 



