448 SCIENCE PROGRESS 



The green pigment consists in most plants apparently of a 

 mixture of magnesium derivatives, a crystalline chlorophyll, and 

 another chlorophyll or mixture of chlorophylls, the latter of 

 which are esters of the unsaturated alcohol phytol. 



According to Willstatter, the chlorophylls yield, on treatment 

 with alkalis and acids, complex mixtures of bodies of varying 

 basicity known as the phytorhodins and phytochlorins. Other 

 derivatives, obtained by the double action of acids and alkalis, 

 have been described by Schunck and Marchlewski, which are for 

 the most part probably mixtures, and which cannot up to the 

 present be identified with certainty with those described by 

 Willstatter. 



There is a considerable amount of evidence which tends to 

 show that an intimate chemical relationship exists between the 

 green pigments of plants and the red pigments of blood. 



Owing to the large number of products described there is a 

 considerable difficulty in following the literature of chlorophyll 

 chemistry. An attempt has been made above to trace historically 

 the discovery of the more important of these, and it is hoped 

 that the summary given will prove of use to those who desire 

 to follow the future discoveries in this important branch of 

 biological chemistry. 



Note. — For the sake of uniformity, the names of substances 

 such as photochlorin and phytorhodin have been spelt without 

 a terminal e, although many of them are of distinct basic 

 character. 



Literature References 



Principal Papers 



Hoppe-Seyler, Preparation of Chlorophyllan, Zeitsch. physiol. Chem. 1879,3, 339. 



Dichromatinic Acid and Phylloporphyrin, Ibid., 1880, 4, 193. 



Lecithin in Chlorophyll, Ibid., 1881, 5, 75. 



Schunck, Phyllocyanin and Phylloxanthin, Proc. Royal Soc. 1885, 38, 336. 



Properties of Phyllocyanin, Ibid., 1887, 42, 184. 



Phyllotaonin, Ibid., 44, 378. 



Properties of Phyllotaonin, Ibid., 1888, 44, 448. 



Action of Alkalis on Phyllocyanin, Alkachlorophyll, etc., Ibid., 1891, 50, 302. 



Schunck and Marchlewski, Action of Alkalis and Acids on Chlorophyll (general 



summary), Liebig's Annalen, 1894, 278, 329. 



Alkachlorophyll and Phylloporphyrin, Ibid., 1894, 284, 81. 



Properties of Phyllotaonin, Ibid., 1895, 288, 209. 



Similarity of Phylloporphyrin and Hrematoporphyrin, Ibid., 1896, 290, 306. 



Willstatter (with Mieg), Phytochlorins and Phytorhodins, Liebig s Annalen, 



1906, 350, 1. 



