Wakeman—Pigments of Flowering Plants. 825 
acid when the compound was, presumably, first hydrated and 
then dehydrated resulting in a rearrangement of the molecule. 
Butin occurs with butein as a glueoside in the blossoms of 
Butea frondosa, a leguminous plant of India and Burma. It 
crystallizes in small colorless needles melting at 224°-226°. It 
is soluble in alcohol, sparingly soluble in acetic acid and ether, 
almost insoluble in benzene. With alcoholic lead acetate solu¬ 
tion butin forms a pale yellow precipitate, with alcoholic ferric 
chloride a deep green coloration. With cold sulphuric acid it 
first turns red, then goes into solution with a pale yellow color. 
On fusion with caustic potash and a little water at 200°-220°, 
butin yileds protocatechuic acid and resorcinol. 
Though butin is not itself a pigment it dyes mordanted fab¬ 
rics exactly as buetin does. From this behavior it is believed 
that it is changed by the mordants into butein. When boiled 
with a solution of potassium hydroxide and then acidified a 
bright orange crystalline precipitate of butein immediately sep¬ 
arates out. 
Saponarin. 
Certain plants contain in the cell sap of the epidermal cells 
of the leaves a substance which turns blue 1 with iodine. As 
in the case of starch this color disappears upon heating and 
returns again upon cooling. For this reason this substance is 
often mistaken for starch, as it was by its discoverer Sanio 2 in 
1857. Schenk, 3 in the same year, doubted the identity of this 
substance with starch, and Naegeli 4 in 1860 showed that the two 
are not identical. Dufour, 5 in 1885, found this substance in 
about twenty species of plants. 
In 1906 Barger 6 separated the above described substance from 
Saponaria officinalis and called it saponarin. He showed that 
the substance is a glueoside which upon hydrolysis yields glu¬ 
cose and another substance C 15 H 14 0 7 , identical with vitexin from 
Vitex littoralis. 
The substance which turns iodine blue, formerly known as 
soluble starch, has been found in Gagea lutea, 2 in Ornithogalum 
1 Rupe,—Der Natuerlichen Farbstoffe, 2, p. 42. 
2 Bot. Zeit., 15, p. 420. 
3 Bot. Zeit., 15, p. 497, 555. 
4 Zeit. zur. Wissensch. Bot., 2, p. 187. 
6 Bull. Soc. Sci. Nat., 21, p. 227. 
6 Jr. Chem. Soc., 89, p. 1210. 
