114 
CHAS. E. SANDO AND H. H. BARTLETT 
might have been confused with fisetin, and it is extremely hkely that 
quercetin was the flavone which they obtained. Not only is it more 
widely distributed than luteolin, but it is already known from the 
leaves of Rhus rhodanthema? Even on the supposition that Acree 
and Syme incorrectly identified the potash fusion products of their 
flavone, it is still unhkely that they had fisetin, since the evidence 
now at hand seems to show that the latter does not occur in leaves, 
even when present in wood of the same plant. In their papers Acree 
and Syme refer to early work of Schmid^ who did indeed state (er- 
roneously) that one of the products resulting from the potash fusion 
of fisetin was phloroglucinol. His work preceded the determination 
of the constitution of fisetin, and has been superseded. 
McNair made gasoline extractions of Rhus diver siloha T. and G. 
(a species closely allied to R. Toxicodendron) and failed to find any 
flavone at all in the extracts. This result is, of course, what one 
would expect, since both the free flavones and their glucosides are 
insoluble in gasoline. McNair makes the point, which seems to be 
well taken, that since the poison of the poison-ivy is soluble in gasoline, 
whereas the flavone glucosides are not, Acree and Syme cannot have 
been correct in ascribing the poisonous qualities of the plant to such a 
glucoside. On the contrary, his negative work obviously has no 
bearing on the question of what flavones occur in the poison-ivy. 
The Wood Pigment, Fisetin 
The wood of R. typhina was collected near Washington, D. C. 
A single log, four feet long and about seven inches in diameter, afforded 
all the material used. The wood of R. glabra was all collected from a 
single thicket near Ann Arbor, Michigan. The maximum diameter of 
the sticks was about 2 inches. In the case of each species the method 
of extracting the flavone, which proved to be fisetin, was as follows. 
The white sap wood was removed, and the yellow heart wood reduced 
to small chips, which were boiled for several days with successive 
portions of distilled water. The decoctions were combined, evaporated 
to small bulk, filtered, and shaken out with ether. The impure 
ethereal solution of fisetin thus obtained was evaporated and the 
residue extracted repeatedly with water, in which fisetin is practically 
insoluble, whereas certain colored impurities are soluble. It was then 
^ Schmid, Jakob. Ueber das Fisetin, den Farbstoff des Fisetholzes. Ber. 
Deutsch. Chem. Ges. 19: 1 734-1 749. 1886. 
