Note 8 — GENERAL OBSERVATIONS.

Sulphate of quinine may be procured by digesting bruised bark in repeated portions of diluted sulphuric acid, until the liquor no longer possess a bitter taste. The different liquors are then to be mixed together and strained. To the strained liquid, lime is to be added, until the mixture assume a chocolate brown appearance, and a precipitate subside to the bottom of the vessel. This precipitate must be washed with a little cold water, dried, and digested in alcohol. The alcoholic solution, when submitted to distillation, leaves, in the retort, a brown viscous liquid, which is to be treated with a suitable quantity of boiling dilute sulphuric acid and a portion of charcoal. This solution is lastly to be filtered, and set aside to cool, when crystals of the sulphate of quinine will form. Mr. Garden informs me, that the largest portion of the sulphate of quinine which he has been able to prepare from the best yellow bark, is as one to fifty.