Some Constituents of the Poison Ivy Plant (Rhus Toxicodendron)Syme, William Anderson
Science
Some Constituents of the Poison Ivy Plant (Rhus Toxicodendron)
Syme, William Anderson
Poison ivy
288 grams of the original poisonous material were extracted with 50 per
cent. alcohol, and this alcoholic solution was precipitated with lead
acetate in the manner already described (p. 17). The lead precipitate so
obtained was extracted with ether in Soxhlet extractors and after the
extraction was found by test to be free from poison. Therefore the
poison, if precipitated by the lead acetate, must have been extracted by
the ether. This ether solution had a dark green color, and was acid from
acetic acid brought down in the lead precipitate. The ether was
evaporated in a vacuum desiccator without heat and there remained a
small quantity of an acid mixture of water and a soft tar; the watery
part was colored green, showing that the tar was soluble to some extent
in dilute acetic acid. The mixture had the peculiar odor of the original
material. A small drop of the green watery part was applied to the
wrist, allowed to remain a few minutes and was then removed by absorbent
paper, but the spot was not washed. Itching and reddening of the skin
commenced within twenty-four hours. At the end of forty-eight hours,
there was a well developed case of poisoning. How this was cured will be
described in another place.
A small portion of the poisonous mixture was dissolved in alcohol, and
this solution was divided into three parts. The first part was treated
with ferric chloride, but it gave no color reaction. Another portion of
the alcoholic solution was diluted with water. It became turbid. The
third portion gave a dirty-green precipitate with lead acetate, which
seemed to come down more readily when the solution was diluted with
water. The main portion of the poisonous mixture was then dissolved in
95 per cent. alcohol and lead acetate in 50 per cent. alcohol was added.
The precipitate was filtered, washed, and decomposed by hydrogen
sulphide in a mixture of water and ether. The ether solution was
filtered and evaporated. The residue was a tar which, on standing in a
desiccator for some time, became dry enough to break into sticky lumps.
An alcoholic solution of this substance gave a dark color with ferric
chloride and a light colored precipitate with lead acetate.
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