Ormnic Substances 125 



fc5 



diex^^ drew the conclusion that EC granules must contain an 

 o- or a p-diphenol or aminophenol or diamine. Cordier and 

 Lison,^^ in a later paper, found that all possibilities except 

 that of an o-diphenol, with a short-chained substituent in one 

 of the p-positions (there are two such positions on account 

 of the two phenohc hydroxyls), can be ruled out. This view 

 has received general acceptance, in spite of the fact that it 

 does not explain either the discrepancies between the behav- 

 ior of adrenalin and the EC substance or the slowness with 

 which EC granules reduce alkaline silver solutions. Lison^ 

 thinks that adrenalin is simply not fixed by formalin, while 

 the EC substance ( or its protein matrix ) is. It would be dif- 

 ficult to ascertain the correctness or incorrectness of this 

 theory, the products of fixation being invisible. On the other 

 hand, formalin-iodate or formalin-dichromate mixtures do 

 fix both adrenalin and EC substance in the form of sharply 

 locahzed brownish granules; yet adrenahn loses its typical 

 reactions, while the EC granules retain them. Also, deriva- 

 tives of catechol (adrenalin, 3,4-dihydroxyphenylalanine ) 

 and of hydroquinone ( homogentisic acid) reduce silver solu- 

 tions in a matter of seconds, while the EC granules require 

 hours. 



In Coujard slides the reactions of resorcinol are invariably 

 identical with those of the EC granules,^^ including the 

 shade of the azo dyes produced and even the staining by 

 gallocyanin and celestin blue. On the basis of these observa- 

 tions, it appears safe to assume that the EC substance is a 

 derivative of resorcinol and not of catechol. 



The EC cells fluoresce intensely in ultraviolet light.^"^ From 

 his comparative studies of their fluorescence spectrum, Jacob- 

 son^* came to the conclusion that these cells contain some 

 derivative of pteridine. The evidence in favor of this assertion 

 is convincing. However, his other theory, namely, that the 

 typical reactions of the EC cells are due to a pteridine com- 



27. Eros, G.: Zentralbl. f. allg. Path. u. path. Anat., 54:385, 1932. 



28. Jacobson, "W.: J. Path. & Bact, 49:1, 1939. 



