Methylene Blue, methylthionine chloride or 3,7-bis(dimethylamino)phenothiazin-5-ium chloride is a chemical compound used as a dye and medication for Gram's stain, Wright stain[?], and the treatment of metoxyhemoglobinemia.
... winner of the Nobel Peace Prize
April 16 - Fifi D'Orsay, actress (+ 1983)
April 22 - Robert Oppenheimer, physicist (+ 1967)
May 6 - Harry Martinson, swedish ...