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 she again patrolled of Ras Aamer. From 11 to 23 February, 1942 she was deployed to an area off the coast of Cyrenaica. From 8 to 21 April, 1942 again she was again deployed off the coast of Cyrenaica. From 1 June to 9 June, 1942 and then again from June 15 to 18, 1942 "Malachite" was posted northwest of Algiers. She was then relocated to patrol off Cape Blanc from 22 to 24 June. On July 16 1942 "Malachite" was sent to patrol along the Tunisian coast, however had to return to the base the next day due to