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
The Malachite Box the Urals. The first short version of the essay, included in the 1939 book, was titled "The Watchhouse on Dumna Mountain". In 1940 the author expanded it and renamed to "By the Old Mine" (). This version was first published in the 3rd volume of the "Uralsky Sovremennik" almanac (1940). Starting with the 3rd edition of "The Malachite Box", this essay was published in all subsequent editions. The author included the essay in every "The Malachite Box" edition for the purpose of familiarizing the reader with the unique culture of the Ural region. "Beloved Name" (alternative translation: That Dear Name)