The following confirmatory tests should be applied: (1) If the substance is treated with a mixture of sulphuric acid and an oxidizing body, such as bichromate of potassa, binoxide of manganese, or peroxide of lead it acquires a violet color, which changes into red and finally passes into a clear yellow; (2) the addition of bichloride of platinum produces a precipitation of the hydrochlorate. Should, however, the substance be only slightly soluble in alcohol, and the above reactions fail to take place, the presence of _solanine_. is indicated. In presence of this alkaloid the following reactions will occur: (1) Upon treating the substance with concentrated sulphuric acid, it assumes a rose tint, which changes after some time has elapsed first to a deep violet, then to a brown color; (2) a solution of a salt of the alkaloid reduces gold and silver salts; (3) the addition of oxalic acid produces a precipitate in the aqueous and even acid solution of its salts. _c. Ammonia fails to produce a precipitate, or redissolves permanently the one formed._ The solubility of the alkaloid in ether is ascertained. If it be soluble, it may consist of aconitine, atropine or codeine; if insoluble, of emetine or morphine. _The alkaloid is soluble in ether._--If bichloride of platinum fails to precipitate the hydrochlorate from a neutral solution of the alkaloid, and sulphuric acid causes it to assume a yellow color which subsequently changes to a reddish-violet, it probably consists of _aconitine_. In case bichloride of platinum causes a precipitate and sulphuric acid fails to produce the yellow coloration referred to above, the presence of either atropine or codeine is indicated. In order to decide which of these bases is present, the substance is dissolved in pure chloric acid and the solution allowed to spontaneously evaporate. If the alkaloid is deposited during this operation, it probably consists of _atropine_. If this is not the case, there is reason to infer the presence of _codeine_. _The alkaloid is insoluble in ether._--If it dissolves in acetone it probably consists of _emetine_. If acetone fails to dissolve it, the presence of _morphine_. is indicated.