THE CHLOROPHYLL APPAEATUS 149 



position are generally found with it in the chloroplast. One 

 of these, Xanfhopliyll, which is of a bright yellow colour, is 

 always extracted with the chlorophyll by alcohol. It can 

 be separated from the extract by appropriate means, and 

 its solution yields the absorption spectrum represented 

 below those of chlorophyll in fig. 84. Another pigment, 

 Eryihrophytt, is present in those leaves which are found upon 

 the trees in autumn. Like xanthophyll, it appears to be 

 a product of the decomposition of chlorophyll, and it has a 

 spectrum which differs from both the others. 



It is extremely difficult to say what is the chemical 

 composition of chlorophyll, on account of the readiness with 

 which it is decomposed. In all the processes which have 

 been adopted for its extraction it undergoes decomposition, 

 and consequently no definite conclusions as to its chemical 

 nature can at present be arrived at. It can be made to 

 yield definite crystals by appropriate methods of treatment 

 after extraction, but it is probable that these crystals are 

 a derivative of chlorophyll and not the pure pigment. 

 Analyses of the crystals have been made by Gautier and by 

 Hoppe-Seyler, who give them the following percentage 

 compositions : 



Gautier. Hoppe-Seyler. 



C 73-97 73-34 



H 9-8 9-72 



N 4-15 5-68 



10-33 9-54 



Ash 1-75 1-72 



According to Hoppe-Seyler the ash contains phosphorus 

 and magnesium. 



From his analysis Gautier came to the conclusion that 

 chlorophyll is related to the colouring matter of the bile ; 

 Hoppe-Seyler considered, on the other hand, that it is a 

 fatty body allied to lecithin. 



Wilstatter found that the phosphorus of the ash is an acci- 

 dental impurity, and hence that chlorophyll is not related 



