Methylthioxinae Hydrochloridum is what the U. S.P. calls Methylene Blue. Tetramethyl-thionine hydrochlorate is the true chemical name, and the matter is mentioned here as a protest against a whole tribe of hybrid synthetic nomenclature in the eighth revision. In large doses, 2 to 6 gr. in capsules, it is an antiseptic eliminated chiefly by the kidneys, and hence is of value in gonorrhea, cystitis, nephritis, diabetes, and pyelitis. In small doses, 1-10 to .% gr., it has some reputation in neuralgias and neurasthenia with a septic or malarial etiology.