Two hundred and eighty-eight grams of the crude material were then extracted several times with 50 per cent. alcohol and filtered; the insoluble tar was washed and saved for examination. To the filtrate was added an excess of a solution of lead acetate in 50 per cent. alcohol. The large precipitate, which will be designated as "precipitate A," was filtered and drained by suction in a Buechner funnel. The alcoholic "filtrate A" was saved. Precipitate A was extracted with ether in Soxhlet extractors until the ether came over practically colorless, the operation being interrupted from time to time to stir up the precipitate in the thimble. The green colored ether solution was saved for future examination. The lead precipitate, after extraction with ether and drying, weighed about 116 grams. A portion of this lead compound was decomposed by hydrogen sulphide in a mixture of water and ether which was well shaken during the operation. The ether was separated, filtered, and evaporated under diminished pressure without heat, and there remained a yellow oily looking residue having a pleasant odor. When the ether and water were completely removed in a vacuum desiccator, a hard, brittle, yellow resin weighing about 16 grams was obtained. It was soluble in alcohol, had a strong acid reaction and was free from nitrogen[16] and sulphur. The nitrogen tests were made by the Lassaign and soda lime methods,[17] and the sulphur test was made with sodium nitroprusside after fusing the residue with sodium. The main portion of the lead compound was decomposed under alcohol by hydrogen sulphide, filtered, and the alcoholic filtrate evaporated in vacuo. The same yellow acid resin was obtained. Experiments continuing through several weeks were made in applying solutions of this resin to rats, rabbits and guinea pigs. Finding it to be without effect upon these animals it was tried on the writer and found to be not poisonous.[18] In the meantime the resin was being studied in the laboratory. GALLIC ACID.