24 
I. N AG AI : 
Name of variety 
Colour of skin when 
fully ripe 
Chromogen P. 
Chromogen F. 
“ Concord ” 
Black 
1 + 
VI 
“ Black Hamburg ” 
?» 
1+ 
VI 
“ Her vert ” 
? * 
If 
VI 
“ Bryan ” 
?» 
1 + 
VI 
“ Delaware ” 
•? 
If 
VI 
“ Gtlielo ” 
Bed 
If 
VI 
“ Bryant” 
?? 
I 
VI 
“ Lady Washington ” 
White 
I f 
VI 
“ Vergennes ” 
?? 
Ilf 
V 
“ Moore’s Diamond ” 
?» 
If 
VI 
“ Niagara ” 
?? 
1 + 
VI 
“ Golden Champion ” 
Amber 
I 
VI 
“Bell,"’ “Esther,” “Eaton” (whites), “Highland,” “ Hartford Prolific ” 
(blacks), and “Iowa” (red) showed likewise the marked colour reaction of 
the chromogenic substance P. 
Apples, pears, oranges, Kaki fruits, strawberries, bananas and other fruits 
and vegetables were examined, the results of which were listed and given in 
Table 13. 
In certain plants, the chromogen reaction failed w r hen tested just before 
the formation of anthocyanin. The leaf scale of the bulb of Liliura tigrinum 
is devoid of anthocyanin when it lies underground. But it becomes pimple in 
exposure to sunlight. Even a few hours exposure causes the purple spots to 
appear on the surface of the yellowish white leaf scale, and the coloured area 
extends gradually to the entire scales, within a few days. The alcoholic 
extract of the suitable material, however, shows practically no reaction of 
either cliromogen. 
The potato tuber is another example of this kind. Two kinds of white 
tubers are known. One is such that the tubers are devoid of anthocyanin as 
long as they are in the ground but by exposure to sunlight, they become 
deep purple. The other is such that, even when exposed to the light for a 
long time, no anthocyanin is produced. The extract of both kinds of white 
tubers showed a very feeble reaction of the chromogens. It seems that the 
anthocyanin may be formed so rapidly from the raw material in these instances 
