At this stage of the work a portion of the resin obtained from lead precipitate A was tested and found to be not poisonous as already mentioned. By this test, all the substances contained in the lead precipitate A after its extraction with ether in the Soxhlet apparatus, were eliminated from the possible poisonous substances. The poison must therefore have been extracted by the ether. A fresh portion of the original poisonous material was treated with 50 per cent. alcohol and filtered from insoluble tar. The filtrate was precipitated in six fractions by lead acetate. The last fractions were lighter in color and apparently much purer than the first. The sixth lead precipitate was decomposed by hydrogen sulphide, the light-yellow water solution was tested and found to be not poisonous. It gave the characteristic reactions for gallic acid. The poison, if precipitated at all by lead acetate, must have gone down in one of the preceding fractions. Later experiments showed that it is brought down partly mechanically and partly as a lead compound in the first precipitates. FISETIN. Having identified gallic acid, and not finding any other phenol derivative in the lead precipitate, some of the original material was extracted with hot water to remove gallic acid and filtered from tar while hot. The filtrate had a deep yellow color. On cooling over night, an olive green precipitate separated out which was dried and found to be a light powder. It was practically insoluble in cold water, soluble with great difficulty in boiling water from which it separated in yellow flakes, slightly soluble in ether and in acetic acid, but readily soluble in alcohol. The solutions were not acid to litmus, gave a dark color with ferric chloride, an orange-red precipitate with lead acetate which was easily soluble in acetic acid, and an orange-yellow precipitate with stannous chloride. These properties and reactions indicated that the substance was the dye-stuff fisetin and that it occurs in the free state in this plant though it is usually found as a glucoside of fisetin combined with tannic acid. A compound of this kind was found in _Rhus cotinus_ and named "fustin-tannide" by Schmid[22]. He showed that the fustin-tannide could be decomposed by acetic acid into tannic acid and a glucoside, fustin C_{46}H_{42}O_{21}. Fustin, on heating with dilute sulphuric acid, gave fisetin and a sugar supposed to be rhamnose. Fisetin was also found as a glucoside compound in _Rhus rhodanthema_ by Perkin.[23] The yellow substance which separated from the boiling water solution was further purified by dissolving in a small quantity of hot alcohol and adding hot water. On cooling, the yellow substance separated out in a flocculent condition. Examined under the microscope, the flakes appeared to be made up of masses of fine crystals.