Aqua. Water.
Water in the purest natural state obtainable may be used for aqueous solutions, etc., when distilled water is not specified, but distilled water should always be employed in dispensing. Distilled water (Aqua Destillata) is obtained by distilling good spring or tap water, the first portions of the distillate being rejected if a deep yellow tint be obtained with Nessler's reagent. Sterilised water (Aqua Sterilisata) is prepared by boiling a suitable quantity of distilled water for thirty minutes in a hard glass flask closed by a plug of cotton, and repeating the operation twice, without removing the plug, at intervals of twenty-four hours. Water so treated is absolutely sterile, but for the majority of purposes recently distilled water boiled in a closed flask for thirty minutes is employed.
