866 Wisconsin Academy of Sciences, Arts, and Letters. 
sis yields pelargonidin chloride which crystallizes in three dif¬ 
ferent forms. The sulphate crystallizes in needles. 
Willstaetter’s idea of the structure of pelargonidin is ob¬ 
tained from its abbau with 50 per cent potassium hydroxide 
solution when phloroglucin, p-hydrohybenzoic acid, and small 
quantities of protocatechuic acid are obtained. It is isomeric 
with apiginin and galangin. 
Willstaetter found pelargonin in the scarlet flowers of pelar¬ 
gonium zonale , 4 also in the scarlet red varieties of dahlia, 5 known 
as “Uakete” and f< Alt Heidelberg,” also in a violet red variety 
of dahlia. 
PentJiy dr oxides. 
Cyanin. 
The above formula represents the constitution of cyanidin 
hydrochloride according to Willstaetter’s more favored formula. 
As early as 1854 Fremy and Cloez * 1 isolated a blue pigment 
from the cornflower which they called cyanin. According to 
these investigators there are three kinds of pigments in plants, 
the green, called chlorophyll, the yellow known as xanthine and 
xantheine, and the red and blue, which they called cyanin. The 
red and rose colored flowers owe their color to the cyanin col¬ 
ored by acids in the juice of the plant. 
In 1913 Willstaetter and Everest 2 again isolated the blue 
pigment from cornflowers and made it the subject of an exhaus¬ 
tive investigation. They found that cyanin, the pigment, is a 
glucoside which they obtained as the hydrochloride. Upon 
hydrolysis this glucoside gave cyanidin chloride. To the hydro- 
4 Ann., 408, p. 42. 
6 Ann., 408, p. 151. 
1 Jr. de Pharm., 58, p. 249. 
2 Ann., 401, p. 189. 
