2 AKT. 3. T. TCHIMÜRA : ON THE FORMATION OF 



may be mentioned the change of its colour from blue to red by 

 the action of acids, this being looked upon as one of its charac- 

 teristic properties. 



Of the physical properties of anthocyan it is known that 

 the red variety shows an absorption band at F and another at 

 the end of G, that the violet variety shows one at D, with a 

 feeble shade toward the green side and another at the end of 

 the spectrnra, and that the blue variety shows a broad absorption 

 band beginning soon after D and continuing to F.^^ 



The object of the present work has been to study the 

 formation of anthocyan in vegetal )le cells and to ascertain the 

 essential conditions under which this pigment is developed. Red 

 Japanese Hortense seemed to offer suitable material for this study, 

 because of the slowness with which anthocyan passes through 

 the different phases of its development in this plant, and also 

 because of the long duration of its blossoming period. 



The different phases of the development of anthocyan in 

 the petaloid calyx of Hortense may be briefly sketched out as 

 follows : — 



Colourless protanthocyan . 



I 

 Yellow aiithocvaii. 



/ \, 



Keddish aiithocvaii. F)inish anthoovan. 



I ■ I ^ 



Deep red aiithocvan. Deep blue anthocyan. 



.\ ■ . / 



Violet anthocyan in crystals. 



All these colours have been observed under tlie microscope. 

 The young calyx appears at first slightly greenisli to the naked 



1) Husemann, Th.— Die Pflanzenstofte. Ed I. p. 259. (After G. Kraus), 



