_a._ It dissolves completely; absence of strychnia; probable presence of BRUCIA, QUINA (?), or VERATRIA:——the alcoholic solution is evaporated to dryness, and, if quina has been already detected, the residue is divided into two portions, one of which is tested for Brucia, the other for Veratria. _b._ It does not dissolve, or not completely; probable presence of STRYCHNIA, and perhaps also of Brucia and Veratria:——the filtered fluid is divided into two portions, and tested separately as at _a_. 4. The original liquid 1. _a_. may contain Salicine, a proximate vegetable principle closely allied to the alkaloids:——a portion is boiled with hydrochloric acid for some time; the formation of a precipitate shows the presence of SALICIN. (See 2, _below_.)[25] [Footnote 25: For further information on this subject, see the admirable ‘System of Qual. Chem. Anal.,’ by Dr C. R. Fresenius. Churchill.] II. (Larocque and Thibierge.) Terchloride of gold is recommended, by these writers, as a more decisive test for the alkaloids than the ‘double chloride of gold and sodium’ commonly employed for this purpose. The following are the colours of the precipitates which it produces with the aqueous solution of their salts:——BRUCIA, milk-brown, passing into coffee-brown, and lastly chocolate-brown:——CINCHONIA, sulphur yellow:——MORPHIA, yellow, then bluish, and lastly violet; in this last state the gold is reduced, and the precipitate is insoluble in water, alcohol, the caustic alkalies, and sulphuric, nitric, and hydrochloric acid; it forms with aqua regia a solution which is precipitated by protosulphate of iron:——QUINA, buff-coloured:——STRYCHNIA, canary-yellow:——VERATRIA, pale greenish-yellow. All these precipitates, with the exception mentioned, are very soluble in alcohol, insoluble in ether, and only slightly soluble in water. Those with morphia and brucia are sufficiently marked to prevent these alkalies from being mistaken for each other; and those with brucia and strychnia are, in like manner, easily distinguishable.