Note 300 — ON THE THEORY AND ART OF PRESCRIBING. (continued 2)

Some extracts become so hard, that in the state of pill they pass unchanged; this has occurred to me with the extract of logwood. Astringent vegetable matter, in combination with iron, is frequently characterised by a hardness that is not exceeded by ebony, and which is perfectly insoluble; the action of iron upon the petals of the red rose furnishes a very striking instance of this fact; if the petals be beaten in an iron mortar, for some hours, they ultimately become converted into a paste of an intensely black hue; which, when rolled into beads and dried, is susceptible of a most beautiful polish, still retaining the fragrance of the rose. I have seen a necklace of this description; indeed these beads form an article of extensive commerce with the Turks, and are imported into Europe, through Austria, under the name of Rose Beads or Rose Pearls.