Malachite green metabolized into LMG. Only the cation MG is deeply colored, whereas the leuco and alcohol derivatives are not. This difference arises because only the cationic form has extended pi-delocalization, which allows the molecule to absorb visible light. The leuco form of malachite green was first prepared by Hermann Fischer in 1877 by condensing benzaldehyde and dimethylaniline in the molecular ratio 1:2 in the presence of sulfuric acid. Malachite green is traditionally used as a dye. Kilotonnes of MG and related triarylmethane dyes are produced annually for this purpose. MG is active against the oomycete "Saprolegnia", which infects fish eggs in
Italian submarine Malachite a range of at . The boats were armed with six internal torpedo tubes, four in the bow and two in the stern. One reload torpedo was carried for each tube, for a total of twelve. They were also armed with one deck gun for combat on the surface. The light anti-aircraft armament consisted of one or two pairs of machine guns. "Malachite" was built by OTO at their shipyard in Muggiano, laid on 31 August 1935, launched on 15 July 1936 and complaeted on 6 November 1936. After delivery, "Malachite" was assigned to the 13th Squadron based at La