CHAPTER I. 



THE DISTRIBUTION OF HEMOGLOBIN AND ALLIED SUBSTANCES 



IN THE ANIMAL KINGDOM. 



Specific respiratory substances are universally distributed throughout 

 plant and animal life, except probably in some of the very lowest organ- 

 isms. For the most part they are colored, and of a variety of colors and 

 tints, and they exhibit decided variations in their respiratory capacities 

 and other properties. In plant life chlorophyl is preeminently the pigment 

 concerned in the interchange of O and CO 2 ; while in animal life hemo- 

 globin occupies an analogous place, but they are undoubtedly very different 

 in their manner of functionating. In each kingdom the major pigment may 

 be represented or supplemented by physiologically allied bodies, which may 

 or may not be closely related chemically. 



The alliance between chlorophyl and hemoglobin that was first sug- 

 gested by Hoppe-Seyler has been convincingly shown by the investigations 

 of Schunk and Marchlewski (Annal. d. Chem. u. Pharm., 1894, No. 278, 

 349; 1895, No. 284, 81, and No. 288, 209; 1896, No. 290, 306; and March- 

 lewski, Bull, de 1'Acad. des Sciences de Cracovie, etc., 1902; Biochem. 

 Centralbl., 1902-03, i, 215), who obtained from chlorophyl a derivative 

 coloring matter which they termed phylloporphyrin (C 16 H 18 ON 2 new 

 formula C 34 H 38 2 N 4 ), which bears a striking resemblance to hematopor- 

 phyrin, C 34 H 3S 6 N4, an iron-free derivative of hemoglobin, and differing 

 from it only in 4 atoms of O. Moreover, Marchlewski and Zaleski obtained 

 hemopyrrol by reduction from both chlorophyl and hemoglobin. Nencki 

 and Zaleski (Berichte d. deutsch. chem. Ges., 1901, xxiv, 997) attempted 

 to convert hemoporphyrin into phylloporphyrin by reduction, but suc- 

 ceeded in removing only two atoms of O, producing a crystalline inter- 

 mediate body which they named mesoporphyrin (C 16 H 18 O 2 N new formula 

 C 3 4H3 S O 4 N4), and which they believe to be identical with hematoidin. 

 Zaleski (Zeit. f. phys. Chemie, 1902, xxvn, 74) found that from meso- 

 porphyrin and hematoporphyrin similar salt and ester compounds can be 

 obtained; and Marchlewski, in examining the spectra of hemoporphyrin, 

 mesoporphyrin, and phylloporphyrin, found them to be very similar, and 

 distinguishable from one another only by a slight displacement of the 

 absorption bands towards the violet end of the spectrum. According to 

 Schunk and Marchlewski, both chlorophyl and hemoglobin are pyrrol 

 derivatives. 



Chlorophyl in granular form (chloroplastids) has been found in a large 

 number of invertebrates and vertebrates. In certain of these animals, 

 especially in the lowest types, as in the Protozoa, it or an almost identical 



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