QUASSIIN AS A CONTACT INSECTICIDE. 3 
Quassine, the active principle of Quassia amara, is amorphous or crystalline. It has 
been isolated by Winkler. It is colorless, inodorous, opaque, and inalterable in the 
air, slightly soluble in water, much more soluble in water charged with salt or organic 
acids, and in alcohol. 
Action on plants: Plants are not injured by spraying with aqueous extracts of 
quassia.? | 
Quassia.—Constit:: Wood: Picrasmin, ©3;H,,O;9: quassin, C,9H,.03 (or, C32H 4.049 
[?]); quassol, C,)H,,O—H,O; alkaloid; resin; mucilage; pectin—Bark: Quassin; 
alkaloid; resin; pectin. (Quassia amara contains 4 bitter principles; Picrenu excelsa 
contains only 2): quassol,—? 
“Quassiin (C3.H,.0,)) may be obtained in a fairly pure state by exhausting quassia- 
wood with hot water, precipitating the solution with neutral lead acetate, removing 
the excess of lead from the filtrate by sulphuretted hydrogen and shaking the filtered 
liquid with chloroform. On evaporation, the quassiin is obtained nearly colorless, 
and, with some difficulty, in a distinctly crystalline condition. Quassiin has an in- 
tensely and very persistent bitter taste. It is sparingly soluble in cold water, more 
readily in hot water, and is easily soluble in alcohol. Its best solvent is chloroform, 
which extracts quassiin readily from acidulated solutions. 
An aqueous solution of quassiin does not reduce Fehling’s solution cr an ammonio- 
nitrate of silver. The solid substance gives no coloration (or merely yellow) when 
treated with strong sulphuric acid, or with nitric acid 1-25 sp. gr.; nor is any color 
produced on warming. * * * 
A solution of quassiin gives a white precipitate with tannin. The reaction is used 
by Christensen, Oliveri, and others, to isolate quassiin from its solutions, and by 
Enders to separate it from picrotoxin. In the author’s hands the reaction has not 
proved satisfactory. The liquid is very difficult to filter, and the filtrate still retains 
an intensely bitter taste, showing that the precipitation 1s very incomplete. As an 
analytical method the reaction is useless, but it is of some value as a qualitative test. 
The test must be made in cold solution. Possibly a more complete precipitation of 
quasslin by tannic acid might be effected in an alcoholic solution. 
Quasslin gives a brown coloration with ferric chloride. The reaction is best observed 
by moistening a quassiin residue in porcelain with a few drops of a weak alcoholic 
solution of ferric chloride, and applying a gentle heat. A fine mahogany-brown 
coloration is produced.’’ 3 
The quasstin used in the following experiments was extracted 
according to directions given by Allen. It was further found 
that when boiled in alcohol a precipitate formed. This was fil- 
tered off, the filtrate evaporated to dryness over a water bath, and 
the resulting dark resmous material extracted with boiling water. 
When extraction was complete a dark brown crusty material 
remained. The resulting extract was light yellow and_ perfectly 
clear. It was found to be intensely bitter. 
When cool this aqueous soluticn was extracted with chloroform, 
evaporated over a water bath, and weighed and made into a per- 
centage solution. 
1 Bourcart, E., Insecticides, Fungicides and Weedkillers, p. 376. London, 1913. 
* Merkes 1907 Index, ed. 3, p. 366. New York, 1907. 
Allen, A. H., Commercial Organic Analysis, ed. 2 revised and enlarged, v. 3, pt. 3, p. 187-188, Phila- 
delphia, 1896. 
4 Except the solution was not acidulated before extraction with acid. 
