Correct spelling for the English word "myriachit" is [mˈa͡ɪɹɪˌat͡ʃɪt], [mˈaɪɹɪˌatʃɪt], [m_ˈaɪ_ɹ_ɪ__ˌa_tʃ_ɪ_t] (IPA phonetic alphabet).
An affection similar to latah, prevalent in certain parts of Siberia.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.