The officinal acids may be classified as follows:

1. Inorganic Acids

Inorganic Acids. Acidum Sulphuricum, A. Nitricum, A. Hydrochloricum, A. Nitrohydrochloricum Dilutum, A. Phosphoricum Dilutum, A. Sulphurosum, A. Arse-niosum. Of these, Acidum Arseniosum is described under Arsenic, and Acidum Sulphurosum under its own heading.

2. Organic Acids

Organic Acids. Acidum Aceticum, A. Citricum, A. Tartaricum, A. Hydrocyanicum Dilutum, A. Carbolicum, A. Benzoicum, A. Gallicum, and A. Tannicum. Of the organic acids, the first three only will be discussed here; the action and uses of the other substances being but little connected with their properties as acids.