The filtrate A (about two liters) was examined first. It had a light yellow color, contained an excess of lead acetate, and was acid from the acetic acid liberated in the precipitation of the lead compound A.[32] This filtrate was evaporated to dryness under diminished pressure to remove alcohol, water, and acetic acid. The clear distillate had a peculiar odor suggesting both tea and amyl formate. It was saved for examination and was found to be not poisonous. The residue in the dish after evaporation was a tough reddish brown, gummy mass which could be drawn out into fine threads. It had a pleasant sweet odor. It was extracted several times with hot water, each portion being filtered. A brownish yellow powder remained undissolved and was saved. The combined filtrates deposited more of the yellow solid on standing. This powder will be referred to later as "P." The filtered liquid was freed from lead by hydrogen sulphide. The solution then had a lemon yellow color, a sweet odor and was acid from acetic acid. On concentrating the solution by evaporation and making a small portion of it alkaline with sodium hydroxide, the yellow color came out very intense[33]. The alkaline solution reduced Fehling solution and ammoniacal silver nitrate, indicating the presence of a sugar. Another portion of the solution gave a slight precipitate with phenyl hydrazine in the cold. The remainder of the solution was evaporated to dryness, extracted with water, filtered, and again evaporated. A dark sticky syrup was left which was only partly soluble in water. This was treated with water, filtered, and the filtrate was evaporated, the water being replaced from time to time to remove acetic acid. Finally the liquid gave the following tests for rhamnose, besides those already mentioned:
(1) With α-naphthol[34] and sulphuric acid, a purple violet color.
(2) With thymol[35] and sulphuric acid, a red color.
(3) With resorcinol[36] and sulphuric acid, red color.
(4) With orcinol[37] and hydrochloric acid, red color.
(5) With ammonium picrate and sodium picrate, yellowish red color.
(6) With phloroglucinol and hydrochloric acid, red color.
(7) It decolorized an alkaline solution of potassium ferricyanide.
(8) It gave a white precipitate with lead acetate.
The filtrate B (p. 20) from which gallic acid was precipitated by sulphuric acid in four fractions was saved to examine for sugar. To remove gallic acid completely, and other vegetable matter, it was shaken out several times with ether, and was kept at a low temperature with salt and ice for a long time. It was left standing for several weeks, during which time more brown matter separated out and was filtered off. The filtrate was evaporated to a small bulk, cooled, and filtered from crystals of potassium sulphate. The filtrate was evaporated to dryness, the residue taken up in water and filtered through bone-black. Addition of alcohol caused complete precipitation of potassium sulphate. The solution then gave the above mentioned characteristic tests for rhamnose.