288 THE BLOOD. 



their relation to the chlorophyll derivatives. By the action of glacial 

 acetic acid containing HI and of iodophosphonium upon haemin or 

 haomochromogen NENCKI and ZALESKI obtained a markedly char- 

 acteristic pigment, mesoporphyrin, having the formula C 16 H 18 N 2 2 , or, 

 according to ZALESKI, x C34H 38 N 4 O4, and which stands in a certain measure 

 between haematoporphyrin, Ci 6 H 18 X 2 O 37 and the chlorophyll derivative 

 phylloporphyrin, Ci 6 H 18 N 2 O, which is very similar to hsematoporphyrin. 

 By the action of the same reducing agent upon haemin or haemochro- 

 mogen, but under other conditions, we obtain haemopyrrol, C 8 H 13 N, a 

 colorless oil, which in the air gradually changes into urobilin. Haemopyr- 

 rol is produced by the action of the same reducing agents upon the 

 chlorophyll derivative phyllocyanin (NENCKI and MARCHLEWSKI), 

 which, as above remarked, shows a close relation between the blood- 

 pigment and chlorophyll. 



We have numerous investigations by NENCKI and ZALESKI, KUSTER 

 and HAAS, MARCHLEWSKI and BURACZEWSKI and ST. MOSTOWSKI, 

 RETINGER, GOLDMANN and HETPER 2 on hsemopyrrol. These investi- 

 gations have not led to any conclusive results, but show that haemo- 

 pyrrol is not a unit body. KUSTER obtained methyl-ethyl maleinamide 

 as an oxidation product and he considers haemopyrrol as a mixture of 

 two methyl-ethyl pyrrols. According to MARCHLEWSKI it is, on the 

 contrary, a mixture of several substances whose chief constituent is methyl- 

 propyl pyrrol. 



Haematoporphyrin is, according to NENCKI and SIEBER, isomeric with 

 the bile-pigment bilirubin, and like this latter gives a play of colors 

 green, blue, and yellow when treated with fuming nitric acid. 



The hydrochloric-acid compound crystallizes in long brownish-red 

 needles. If the solution in hydrochloric acid is nearly neutralized with 

 caustic soda and then treated with sodium acetate, the pigment separates 

 out as amorphous, brown flakes not readily soluble in amyl alcohol, ether, 

 and chloroform, but readily soluble in ethyl alcohol, alkalies, and dilute 

 mineral acids. The compound with sodium crystallizes as small tufts 

 of brown crystals. The acid alcoholic solutions have a beautiful purple 

 color, which becomes violet-blue on the addition of large quantities of 

 acid. The alkaline solution has a beautiful red color, especially when 

 not too much alkali is present. 



An alcoholic solution of haematoporphyrin, acidulated with hydro- 

 chloric or sulphuric acid, shows two absorption-bands (spectrum plate, 

 7). one of which is fainter and narrower and lies between C and D, near 



1 The works of Kiister and collaborators may. be found in Ber. d. d. chem. Gesellsch., 

 37 and 40, and Zeitschr. f. physiol. Chem., 55, and of Marchlewski and co-workers, 

 in Zeitschr. f. physiol. Chem., 43, 45, 51, 56, and Biochem. Zeitschr., 10. 



2 See footnote 1. 



