PART VI.—ALKALOIDS AND POISONOUS VEGETABLE PRINCIPLES SEPARATED FOR THE MOST PART BY ALCOHOLIC SOLVENTS.
DIVISION I.—VEGETABLE ALKALOIDS.
I.—General Methods of Testing and Extracting Alkaloids.
§ 301. General Tests for Alkaloids.—In order to ascertain whether an alkaloid is present or not, a method of extraction must be pursued which, while disposing of fatty matters, salts, &c., shall dissolve as little as possible of foreign substances—such a method, e.g., as the original process of Stas, or one of its modern modifications.
If to the acid aqueous solution finally obtained by this method a dilute solution of soda be added, drop by drop, until it is rendered feebly alkaline, and no precipitate appear, whatever other poisonous plant-constituents may be present, all ordinary alkaloids[324] are absent.
[324] In the case of morphine tartrate, this test will not answer. See the article on [Morphine].