432 



SCIENCE PROGRESS 



substance, soluble only with difficulty in alcohol and ether, but 

 somewhat more easily in chloroform. It dissolved very readily 

 in mineral acids and in acetic acid, giving violet solutions of 

 fairly stable salts ; from solutions in mineral acids it could not 

 be extracted by ether. It also possessed a somewhat acidic 

 character, although this is not so marked as its basic character. 

 It gave, as already noticed, a characteristic zinc salt. Its analysis 

 agreed fairly with the formula C 3 2H340 2 N 4 . 



Great interest attaches to this body on account of its chemical 

 relationship with the derivative of the blood-pigment haemato- 

 porphyrin which will be discussed again later. 



These experimental methods of preparing the above-described 

 derivatives, together with their chief properties, have been 

 discussed in some detail, in order that a comparison might be 

 instituted between them, and the series of products prepared 

 later by Willstatter and his fellow workers. The relationship 

 of the products prepared by Schunck and Marchlewski is 

 indicated in the accompanying scheme : 



[Boiling with 

 alcoholic NaOH] 



Chlorophyll 

 \ 



Alkachlorophyll 



[Throwing acid 

 solution into 

 hot alcohol] 



Ethyl phyllotaonin 



[Hydrolysis with 

 alkaline NaOH] 



[Weak acid] 



Chlorophyllan (Hoppe-Seyler) 



[Stronger acid] 

 Phylloxanthin 



[Still stronger acid] 

 Phyllocyanin 



[Evaporation with HC1 

 or alkali] 



Phyllotaonin 



[Alkali at 190°] 

 Phylloporphyrin. 



Researches by Willstatter and his Pupils 



Willstatter's earlier researches were directed towards the 

 study of the earlier decomposition products of chlorophyll 

 obtained by the action of acids and alkalis. In the investigations 



