Correct spelling for the English word "Grassion" is [ɡɹˈasi͡ən], [ɡɹˈasiən], [ɡ_ɹ_ˈa_s_iə_n] (IPA phonetic alphabet).
Bituminous waters. Used by drinking in affections of the throat and chest, and in gastric and vesical catarrh.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.