294 The Physiology of Plants BOOK in 



them. They do not seem to be identical with Fremy's 

 pigments. 



In 1877 Fremy thought that his phyllocyanin was the 

 potassium salt of a complex acid. 



Konrad, in 1872, and Pringsheim, in 1874, opposed the 

 views of Fremy, maintaining that chlorophyll is a single 

 pigment, though occurring together with others in smaller 

 amounts in the corpuscle. 



Gautier made analyses of the matter extracted by 

 alcohol, and in 1876 based upon them a view that the 

 pigment is allied to the colouring matter of the bile of 

 animals bilirubin. He attributed to the two the formulae 

 C 16 H 18 N 2 O 3 and C 19 H 2 ,N 2 O 3 respectively. Hoppe-Seyler, 

 in 1879, on the basis of similar analyses of an ether and 

 alcohol extract of leaves, concluded that the pigment, which 

 he found to yield an ash containing magnesium and phos- 

 phoric acid, is allied in its composition to lecithin. He 

 did not, however, consider the residue from his extracts 

 consisted of pure chlorophyll. He termed it chlorophyllan. 



Tschirch identified this substance with a body described 

 by Pringsheim in 1879 under the name of hypochlorin, 

 an acid derivative of chlorophyll. 



In 1895 Schunck and Marchlewski described a derivative 

 of chlorophyll, which has apparently much in common 

 with the colouring matter haematoporphyrin or iron-free 

 haematin, itself a derivative of haemoglobin the pigment of 

 blood. This body, to which they give the name phyllo- 

 porphyrin, exhibits an absorption spectrum almost identical 

 with that of haematoporphyrin, the bands being a little 

 more to the right, but otherwise coinciding. The two pig- 

 ments therefore appear to be related, though perhaps not 

 closely. They seem both to give rise to pyrrol on dry 

 distillation. 



Some observations upon the antecedents of chlorophyll 

 in the leaf were made by Timiriazeff in 1886. Acting upon 



