apothecaries' weights and measures

apothecaries' weights and measures

(ă-pŏth′ĕ-kār″ēz)
An outdated and obsolete system of weights and measures formerly used by physicians and pharmacists; based on 480 grains to 1 oz and 12 oz to 1 lb. It has been replaced by the metric system.

apothecaries' weights and measures

a generally superseded system used for measuring and weighing drugs and solutions. It is gradually being replaced by the metric system.
In the apothecaries' system fractions are used to designate portions of a unit of measure: e.g. one-fourth grain is written gr. 1/4. The fraction 1/2 is written ss.
There are two symbols in this system which are sometimes confused and must always be written clearly. These are the symbols for drams () and ounces (). Small Roman numerals are used after the symbols. For example, iss reads drams one and one-half; iii reads ounces three. See also Tables 4.2 and 4.3.