210 



Dr. 0. A. MacMuim. Researches into the [Dec. 16,. 



treating* febrile urobilin, obtained from a case of pleurisy, with caustic 

 soda (Chart I, sp. 17), and I think this points to the conclusion that 

 normal urobilin has a tendency to pass, when reduced by sodium 

 amalgam, into the condition of febrile urobilin.* Moreover, these 

 bands indicate the source of the pigment in the economy, as similar 

 bands are seen in the spectrum of a pigment obtained from gall-stones 

 (Chart II, sp. 2), in that of the alcoholic extract of bile-colouring 

 matter, and also in that observed when heematoin was reduced by 

 means of sodium amalgam in the neutral state at the ordinary tem- 

 perature, and the fluid examined at an early stage of the reaction. 



A faint band covering D may sometimes be seen in solutions of 

 normal urobilin, but I have not yet determined upon what conditions 

 its presence may depend. (See, however, Chart II, sp. 15.) It can 

 only be seen in deep layers of alcoholic solution. The amount of normal 

 urobilin in urine is small, but what I have been able to obtain after 

 about thirty experiments will suffice to establish its identity. 



This pigment has, up to the present time, been confounded with 

 febrile urobilin, but it will be seen that it is quite a different body. 

 Before I had succeeded in isolating it, I had concluded that it was 

 identical with febrile urobilin, and since this normal urobilin is iden- 

 tical with choletelin, and since the latter pigment is produced by 

 oxidation from bilirubin, I had concluded that febrile urobilin was 

 produced by oxidation. It would appear t\m\j febrile urobilin, although 

 it may represent an intermediate stage of the oxidation of bilirubin, is 

 capable of being produced by reduction of choletelin, and therefore 

 of normal urobilin, and also of a similar body produced by the 

 oxidation of hasmatoin by peroxide of hydrogen. We may conclude 

 that febrile urobilin is the same body as that obtained by Maly, 

 and which he called hydrobilirubin, but that the present pigment is 

 an entirely different body, and is produced by oxidation. But there 

 is another body present in urine which is capable of passing into the 

 condition of febrile urobilin when strong oxidising agents are made to 

 act on the urine, in fact, it may be accepted as an established truth, 

 that the chromogen of febrile urobilin exists in normal urine. Disquef 

 believes that it is this body which furnishes urobilin when urine is 

 treated with acids, and that it is oxidised in the presence of chloro- 

 form into that body. Such may be true in some cases, but not in all, 

 as the following experiment will show. When a stream of chlorine is 

 passed through perfectly normal urine, or when this fluid is treated 

 with permanganate of potassium, bromine in aqueous solution, or 

 ozone, the colour soon changes to yellowish-red, and a black band is 

 seen at F. When caustic soda is added after such treatment, this 



* Again, they may be seen when normal urobilin lias more of a brownish tinge, 

 hj treatment with caustic soda alone. 

 f " Chem. Centr.," 1878, s. 711. 



