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 December 1942 she patrolled an area between the island of La Galite and Cape de Fer. She patrolled off the island of La Galite on January 4 and 5 1943 again. On January 21 "Malachite" was deployed to an area between Cape Carbon and Cape Bougaroun. At 4:55 on January 22 she sighted an incoming convoy heading to Bona. At 05:18 she fired four torpedoes, and dove to avoid an attack by the escorts. Two explosions were heard, but again British post-war documents contain no mention of this attack. On February 2, 1943 "Malachite" left Cagliari with a group of