114 Scientific Proceedings, Royal Dublin Society. 



St. von Kostaneeki and V. Lanipe, 1 assuming that a compound which 



contains the grouping /„ q \ would split off water more easily than 



catechin does, replaced the chromane formula of Perkin and Toshitake by 



the coumarane formula 



OH 



HO/\ HO/\/\CH 2 



X/ J CHOH l x/ ! 1 CH 2 



OH 



The chromane formula has nevertheless some advantages which are not 

 possessed by that of von Kostaneeki and Lampe. 



It has been pointed out by A. Gr. Perkin, 2 that there is a very close 

 relationship between the nuclear groups of tannins and those of the 

 flavone dyes which occur associated with the tannins in many plants. 

 Thus catechin and quercetin, which occur in catechu, both contain the 

 catechol and the phloroglucinol nuclei. Pacts such as these, which can 

 scarcely be regarded as casual coincidences, suggest the probability that 

 the flavone dyes — and the same may be said of the members of the antho- 

 cyan group, the chemical nature of which has recently been elucidated by 

 Willstaetter and his pupils — are formed in the plants from the more widely 

 distributed phloba-tannins. Thus it is easy to see that catechol-tannin, if it 

 has the formula given to it by Perkin and Yoshitake, may pass by the 

 relatively simple processes of oxidation and dehydration into either cyanidin 

 or quercetin :— 



OH 



HO/\/\CH_ / -\ 



\/\/CHOH ' 



OH CH 2 

 Catechol-Tannin. 



OH 



HO/\/\COH/-\ 



I I I \_/ 



\/\/CHOH 



OH CHOH 



'Norscoparin.' 



--— — > CI 



o 6 



HO/\/\C . C 6 Hs(OH) 2 HO./\/\C . C c H 3 (OH) 2 



III! . I I II 



\/\/C . OH \/\/C . OH 



OH CO OH CH 



Quercetin. Cyanidin Chloride. 



In support of the view here put forward we may mention that the substance 

 known to botanists as " soluble starch," which occurs in the epidermis of the 



1 Ber. d. Deutsoh. Chem. Ges., 1906, xxxix., p. 4007. 



2 Journ. Chem. Soc, 1897, lxxi., p. 1138. 





