This salt is an object of some importance to the medical jurist, as it
forms the basis of a common medicine, Fowler’s Solution, or the
Tasteless Ague Drop. This preparation contains in every ounce four
grains of arsenious acid. It has a brownish-red colour, and an odour of
lavender. It is strongly alkaline to litmus. When acidulated with
hydrochloric acid, hydrosulphuric-acid gas causes in it a dirty
brownish-yellow precipitate; and Reinsch’s process will detach arsenic
from it upon copper in a state capable of being subjected to the usual
tests [see p. 214].