218 Dr. C. A. MacMunn. Researches into the [Dec. 16, 



green in colonr, and it was then dissolved in alcohol. The solution was 

 then filtered so as to catch any unchanged bilirubin. The filtrate was 

 then seen to be a brilliant sap-green colour and gave only general 

 absorption of the spectrum. It was now treated with strong nitric 

 acid, and examined with the spectroscope. When the bands on each 

 side of D had completely disappeared, leaving one at F of intensity f$ 

 or 7 from wave-length 507 to 482, the solution was shaken with chloro- 

 form in a separating funnel, and the reddish-yellow chloroform layer 

 was separated off, and filtered. After evaporation of the chloroform, a 

 brownish-yellow, or yellowish-brown amorphous pigment was left, 

 soluble in the same solvents as normal urobilin. This pigment, when 

 dissolved in alcohol, gave a yellow solution, and when looked at in a 

 white dish, it had a slightly reddish tinge at the edge, where it 

 touched the white surface of the dish, this being better marked in a 

 chloroformic solution. The alcoholic solution gave a band of intensity 

 /3, from wave-length 510 to 482, having ill-defined edges. When 

 the fluid was treated with caustic soda, it became of an orange colour, 

 and then general absorption of the violet end of the spectrum was 

 noticed. In a moderately deep layer, the dark shading commenced at 

 wave-length 510. No band could be seen in a thinner layer. When 

 caustic soda was added after the addition of zinc chloride, the reddish 

 colour produced by the zinc chloride became yellow, and I then per- 

 ceived a feeble band from wave-length 516 to 488, but it was difficult 

 to take the reading of this band. Sodium amalgam produced exactly 

 the same effect that it produced with the pigment got by the action 

 of chlorine, and the description given before will apply word for word 

 to the present pigment. 



Action of Ozone on Pure Bilirubin. — Fearing that nitric acid might 

 not have produced the pigment by oxidation, I planned an experiment 

 by which ozone was made to act on bilirubin dissolved in chloroform. 

 A Siemens induction tube* was made by taking two test-tubes, 

 one larger than the other ; the inner surface of the small tube was 

 coated with tin- foil, and the outer surface of the larger one. They 

 were kept from touching each other by four small points of sealing-wax 

 when one was placed within the other. All the space between the 

 tubes was closed, except a hole at either end of the larger tube, into 

 which a small glass tube was fastened. So that I had two concentric 

 tubes, coated, the inner one on the inside and the outer one on the out- 

 side, with tin-foil, and containing a space between them through which 

 oxygen could be passed. The coatings were respectively connected 

 with the terminals of a Ruhmkorff's induction coil, worked by a 

 quart bichromate cell. When oxygen was then passed into one end of 

 the space between the tubes, it came out ozonised through the small 



* " Bloxam's Chemistry," 4th ed. (1S80), p. 53. 



