CHLOROPHYLL 233 



CH = CH 

 CH.^— C CH C — C 



1 >N ,.< I 



C, H5 • C C^^ \ / ^C CH 



C2 Hg- C = C \ / C = C ■ C2 Hg 



I ^N — kg N^ I 



CH3 ■ C =C c = CCH, 



I I » 



CH3 CH3 



Aetiophyllin C^iHjj^N^Mg 



T/ie Action of Acids. 



Acids, especially oxalic acid, remove magnesium from all 

 derivatives containing this element, replacing it by two atoms 

 ot hydrogen without altering the rest of the molecule. 



Thus chlorophyll a and b give by removal of Mg the com- 

 pounds 



'COOCH3 



,> and 



\COOC20H39 

 'COOCH3 



Ph£Eophytin a CaaH^jONjC 



Phasophytin h CoHgoOgN/. 



XcOOC^oHga 



respectively, while chlorophyllin a gives phytochlorin / and 

 g, Cg^HgoON.CCOOHX. On the other hand, glauco and 

 rhodophyllin by removal of magnesium give glauco and 

 rhodoporphyrin C3iH3jN/COOH)2, while pyrrophyllin yields 

 pyrroporphyrin C3iH3.N4(COOH). By removing the last car- 

 boxyl from the latter compound a substance aetioporphyrin 

 C3^H3,;N4 is obtained, which is the magnesium free analogue 

 of aetiophyllin CgiHg^N^Mg. 



CRYSTALLINE AND AMORPHOUS CHLOROPHYLL. 



The physical constants of these substances as determined 



by "VVillstatter and his pupils are as follows : — 



