528 SCIENCE PROGRESS 



the name phylloporphyrin. The chemical relationship of the 

 two bodies could be expressed by the two following formulae : 

 Haematoporphyrin = C 3 4H 38 6 N 4 

 Phylloporphyrin = Ca^gO^ 

 The relationship of the empirical formulae between the blood- 

 pigment and chlorophyll demonstrated by Schunck and 

 Marchlewski induced Nencki and Zaleski to attempt to convert 

 by reduction the haematoporphyrin, derived from the former 

 body, into the phylloporphyrin derived from the latter. They 

 succeeded, however, in obtaining another product — viz. 

 C34H3JJO4N2, which stands intermediate between the two — to 

 which they gave the name mesoporphyrin. In addition to this 

 a volatile substance, haemopyrrol, was obtained, which readily 

 oxidises to the pigment urobilin, which is found in urine after 

 blood extravasations. 



Although phylloporphyrin was not directly obtained from 

 haematoporphyrin, there seemed very little doubt of their 

 intimate chemical relationship. From this stage Nencki and 

 Marchlewski continued their work conjointly, and they sub- 

 sequently showed that phyllocyanin (see above), on reduction, 

 also yields haemopyrrol. 



This body has probably the following formula : 



CHaC C • C 3 H 7 



HC CH 



NH 



i.e. it is methyl-propyl-pyrrol. 



As the result of their researches, and those of Kilster, who 

 had in the meantime been investigating the oxidation products 

 of haematin, Nencki and Zaleski endeavoured to assign a 

 formula to haematin. The constitution of this body, however, 

 is still far from being established with certainty, and it is very 

 improbable that the formula assigned to it is correct. It is 

 hardly necessary to reproduce it here. 



The constitution of chlorophyll has recently been the subject 

 of investigations by Willstatter. Some preliminary results 

 have been already made public, which are of great interest, and 

 lead to the expectation that much may be accomplished in the 

 immediate future. 1 



1 See recent number of Liebig's Annalen. 



