b. A precipitate is formed:—solution of potassa or soda is added, drop by drop, until the liquid exhibits a strong alkaline reaction:—
α. The precipitate redissolves; absence of Brucia, Cinchonia, Narcotina, Quina, Strychnia, and Veratria; probable presence of Morphia.
β. Precipitate does not redissolve, or not completely; probable presence of one or more of the first six of the above-named alkaloids:—the fluid is filtered from the precipitate, mixed with either bicarbonate of soda or of potassa, gently boiled nearly to dryness, and treated with water. If it dissolves completely; absence of morphia; an insoluble residue indicates Morphia.
2. The precipitate 1. b. β. is washed with cold distilled water, dissolved in a slight excess of dilute sulphuric acid, neutralised with a saturated solution of bicarbonate of soda, and allowed to repose a few hours:[24]—
[24] Before setting the glass aside the liquor should be well mixed, and the glass stirrer vigorously rubbed against the sides of the vessel.
a. No precipitate; absence of Cinchonia, Narcotina, and Quina:—the solution is gently evaporated nearly to dryness, and treated with cold water:—if it dissolves completely, pass on to 4; if there is an insoluble residue, it may contain Brucia, Strychnia, or Veratria. (See 3.)
b. A precipitate:—the filtered fluid is treated as directed at 2 a.; the precipitate is washed with cold distilled water, dissolved in a little hydrochloric acid, ammonia is added in excess, and subsequently a sufficient quantity of ether, agitation being had recourse to:—
α. The precipitate formed by the ammonia redissolves completely in the ether, and the clear fluid separates into two layers; absence of Cinchonia; probable presence of Quina or Narcotina.
β. The precipitate produced by the ammonia does not redissolve in the ether, or not completely; probable presence of Cinchonia, and perhaps also of Quina or Narcotina. The filtered liquid may be tested for these alkaloids as at a.
3. The insoluble residuum after the evaporation of the solution 2. a., or of the filtrate 2. b., is now dried in a water bath, and digested with absolute alcohol:—