12 



PHYSIOLOGY OF NUTRITION 



crystals, is slightly soluble in alcohol and ether, and more readily soluble 

 in chloroform. The absorption spectrum of its ethereal solution (Fig. 7) 

 exhibits seven absorption bands, the first of which lies to the right of the red 

 region of the spectrum, between C and D, and is very distinct. 



Phylloporphyrin is of great interest because of its close relationship to 

 hemato porphyrin, which was obtained by Nentskii and Sieber from hemoglobin 

 of animal blood. Hematoporphyrin has the composition Ci6Hi8N 2 3 , the dif- 

 ference between it and phylloporphyrin, as represented by these formulas, con- 

 sisting in the lower oxygen content of the latter. 1 The method used in the 

 isolation of hematoporphyrin is also analogous to that employed for phyllopor- 

 phyrin. The spectra of these two substances, in various solvents, 2 are almost 

 identical, except that the absorption bands of hematoporphyrin sometimes 

 appear slightly displaced toward the red (Fig. 7). 



Fig. 7. — Absorption spectra of phylloporphyrin (i, 3, 5) and of hematoporphyrin (2, 4, 6); 

 1 and 2 in ether; 3 and 4 in hydrochloric acid; 5 and 6 in zinc chloride solution. {After Schunck 

 and Marchlewski.) 



Both hematoporphyrin and phylloporphyrin, when heated in a test-tube, 

 form a vapor which gives a red color to pine sawdust moistened with hydro- 

 chloric acid, a characteristic indication of the presence of the pyrrol ring 

 (C4H5N): the characteristic odor of pyrrol may also be plainly recognized in 

 this vapor. 3 It thus appears that chlorophyll (acting synthetically) and hemo- 

 globin (acting analytically) are closely related, in that the pyrrol ring is common 

 to both. It is of great interest also to note that the bile pigment bilirubin 

 has the same percentage formula as hematoporphyrin (Ci 6 Hi 8 N20 3 ). Further- 

 more, Nentskii and Zaliesskii 4 succeeded in obtaining mesoporphyrin from hemin, 



1 For the difference in structure between the two compounds see: Willstatter, Richard, and Asahina, 

 Yasuhiko, Oxydation der Chlorophyllderivate. Liebig's Ann. Chem. u. Pharm. 373 : 227-238. 1010. 



2 Schunck, E., and Marchlewski, L., Zur Chemie des Chlorophylls. (Vierte Abhandlung.) Liebig's 

 Ann. Chem. u. Pharm. 290: 306-313. 1896. 



3 Schunck, E., and Marchlewski, L-, Zur Chemie des Chlorophylls. (Dritte Abhandlung.) Liebig's 

 Ann. Chem. u. Pharm. 288: 209-218. 1895. 



4 Nencki, M., and Zaleski, J. Ueber die Reductionsproducte des Hamins durch J odwasserstoff and 

 Phosphoniumjodid und liber die Constitution des Hamins and seiner Derivate. Ber. Deutsch. Chem. Ges. 

 34^:997-1010. 1901. 



