Correct spelling for the English word "novargan" is [nˈɒvɑːɡən], [nˈɒvɑːɡən], [n_ˈɒ_v_ɑː_ɡ_ə_n] (IPA phonetic alphabet).
A trade name for silver proteinate; similar in composition and action to protargol.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.