16 I. NAG.U ; 



aud exposed to day light, a deep violet-red coloiu' develops. The colom-ed 

 scales were removed and the white portions were kept in the same manner 

 as in the previous experiment ^vith the common onion bidhs. No red pigment 

 was formed during the experiment Mhich lasted for two weeks. The bullös in 

 the conti'ol Ijecame deep gi-een and the treated ones were white. Alcoholic 

 exti-acts were prepared, and the flavone content was examined. They showed : 



Ti-eated No reaction 



Control Trace of pink colom- 



Here the flavone was formed in exti-emely shght amoimt even when the 

 light and the air relation was normal. 



5. A Geoit of Si.tbstanc'es of Unknown Chemical Nature 



A.S THE ChEOMOGEN OF AnTHOCYANINH AND 



Reddish Brown Pigments. 



A body of evidences accumulated by the diflerent iuvestigatoi-s show' that 

 a gi'oup of chixjmogenic substance is present in plants which gives rise to 

 anthocyanin-like pigments as well as the brown pigments. 



Wolff and Kouchermann (1915)- observed the presence of a chromogenic 

 substfince in a number of plants which are sensitive to the action of Laccase 

 .yielding the brown pigment. The phenomena observed in iodine coloiu- tests 

 are always pi-eceded by the action of a laccase. The authore considered that 

 the chi-omogens are of the same kind in diflerent plants and the brown 

 pigments Avhich are formed in various plants or organs might lie regarded as 

 products of oxidation. Shibata' obtained the chromogenic substance fi'om a 



1. Mai.vezin, Ph., Sur 1 'origine de la coIoiu ties misins rouges. Comp. Eencl. Acad. Sei. 

 Taris. 147 : 318, 1908 ; Laboede, J., Siir 1 'origine de la matiere colorante des raisins rouges et 

 mitres orgones vegetans. Ibid. 146 : 1411, 1908 ; Dezani, S., Le sostanze cromogene dell' uva 

 bianca. Staz. sper. agr. ital., Modena. 43 : 328, 1910 (cited in Atkins, "\V. E. G., Kesearclies in 

 Plant Physiology. 1916) (also in Jour. Chem. Soc , Abstract 100 : 223, 1911.) ; Keegax, P. Q , Tlic 

 Chetaistry of the Flower Pigments. Chem. News. 107 : 181. 1913 ; Tswett. M., Zur Kenntnis des 

 vegetabilischen Chama-Ieons. l?er. d. d. bot. Gesell, 32 : Gl. 1914; Tswett. M.. BeitCige zur 

 Kenntnis der Anthocyane. Uebcr künstrichcs Anthocyan. Bioch. Zeit. 58 : 225. 1913. 



2. ■\VoLFF, .T. und EoDCHEKiUNN, K., Sur les proxirietes d'un chromogene universellement 

 repandu dans les vegetaiux. Comp. Eend. Acnd. Sei. Paris. 161 : 399, 1915 : 'WoLrF, J., PhenomC-nes 

 d" oxidation et de reduction portant sur les chromogenes des vegetaiuc. Had. 160 : 716. 1915. 



3. Shibata, K, Bot. Mag. Tokyo. 31 : 1919. A brief note in Japanese. 



