400-5 
Arbutin, during its passage through the body, undergoes the following change,* 
which is also brought about outside the body by the action of emulsin, or by boil- 
ing with dilute siipburke acid : 
Arbutin, Water, Glucose. Hydrokinone, Methyl-hydrokinone. 
Cyl yO) +288 = CHO, + C,H (OH), +.C,H (OHOCH)). 
fLydrokinone,+ C,H,O,.—This dioxybenzene forms in colorless rhombic prisms, 
melting at 169°-172° (336.2°-341.6° F.), and subliming, partly decomposed, at 
higher temperatures, 
In the mother-liquor, after the crystallization of Arbutin, the following sub- 
stances are found: 
Ericolin, C,,H,,O,,.—This amorphous, very bitter glucoside results as a yellow- 
ish-brown mass, softening at 100° (212° F.), and resolving, under the action of 
dilute sulphuric acid, as follows: 
Ericolin. Water. Glucose. Ericinol. 
C,,H,,0,, + 4H,O —4C,H,,O, + C,,H,,0. 
Lricinol, C,,H,,O, is a yellowish, or nearly colorless resinifying oil, having a 
peculiar odor.{ . It also exists free in the volatile oils of many Ericacez ; that from 
Ledum having a blue-green color, a disagreeable odor, a burning and bitter taste, 
and boils at 240°—250° (464°—482° F.). On boiling it with hydrated lime it yields 
a hydrocarbon of the composition C,,H,,.§ 
Urson, C,,H,,O,.||—-This colorless, tasteless, crystalline body melts at 198°- 
200° (388.4°-392° F.), sublimes at higher temperatures without visible change, is 
insoluble in water, and slightly soluble in alcohol and ether.§ 
Gallic, or 77zoxybenzoic, Acid, C,H,O,(OH),.—This acid occurs in a free state 
in this and many other plants, and, in combination with tannic acid, in numberless 
others; it dissolves in 100 parts of cold water, from which it crystallizes in fine, 
silky needles, slightly acid and astringent. Gallic acid gives a deep blue color 
with ferric salts, melts at 200° (392° F.), and resolves at 210° (410° F.), as follows: 
: ‘ Carbonic Pyrogallic 
Gallic Acid. Dioxide. Acid. 
C,H,0,(OH), gue CO, Z CHO, 
Tannin.—This glucoside is generally considered to have the composition 
C,,H,,O,, which proves it an anhydride of gallic acid, and its true name Digallic 
Acid. The difficulty of obtaining tannin pure renders its composition, however, a : 
somewhat doubtful; when as pure as possible it results as a porous, greenish- 
yellow, friable mass, freely soluble in water, less so in alcohol, and insoluble in 
ether. The tannic acids, so called, are a group of bodies widely diffused through 
the vegetable , Kingdom, the species containing them usually lending a portion of Se 
* M, voh “Mering, Arch. f. ad. gesam, Physiol. 1877, 276. ah % Wittstein. 
+ Arctuvin, Quinhydrone, Hydroquinone, Hydrochinone, — . + Gallic Atid. 
{ Gmelin, Chem., xvi, 28. me : (CHO ae 
