Correct spelling for the English word "nastin" is [nˈastɪn], [nˈastɪn], [n_ˈa_s_t_ɪ_n] (IPA phonetic alphabet).
A fatty body extracted from a culture of Streptothrix leproides by Deycke and Reschad Bey, which it is claimed will produce in conjunction with benzoyl chloride an active immunity against the lepra bacillus and other acid-fast bacilli, including the tubercle bacillus.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.