This is common chalk, the coarser particles of which have been removed
by the mechanical operation of washing. It consists of carbonate of
lime, with various earthy impurities. The Dublin Pharmacopœia directs a
chemical process for obtaining a perfectly pure carbonate (_Creta
Præcipitata_), but it appears to be an unnecessary refinement. MED.
USES. It is antacid and absorbent, on which account it is useful in
acidities of the primæ viæ, and in diarrhœas, after removing all
irritating matters by previous evacuation. (_Form. 52._) From its
absorbent properties, it is a good external application to ulcers
discharging a thin ichorous matter. DOSE, grs. x to ℈ij, or more. It is
almost unnecessary to state that it must not be combined with acidulous
salts; I have however seen a formula for a powder, intended as an
astringent, in which chalk and alum entered as ingredients. OFFICINAL
PREP. _Hydrargyrum cum creta._ L. _Pulvis cretæ comp._ L.E. _Pulv.
Opiatus._ E. (=F=) _Mist. Cretæ._ L.E. _Trochisci Carbonatis Calcis._ E.
_Confectio Aromatica._ L.E. (=G=)