Malachit Green

MALACHIT GREEN, malakhitovaya zelen' (syn. benzoylgrün), a derivative of diphenylmethane, a coloring substance very close in its properties to methyl green (see Methyl Green), but inferior to it in its dyeing abilities and therefore comparatively little used at present in microscopy and histological technique. It possesses fixing and disinfecting properties. M. is also used in microphotography as a light filter. In 1928, Bakkal proposed using M. instead of iodine tincture for sterilizing catgut, silk, the operative field, and cutting instruments. The bactericidal properties of M. in vitro are high; it inhibits the growth of the anthrax bacillus in serum at a dilution of 1:40,000 (Gabrichevsky; 1907); the staphylococcus perishes within 5 minutes at a dilution of 1:4,000, and the bacillus coli in the same period at a dilution of 1:300 (Bakkal). Catgut, wound loosely on a glass beaker, is sterilized in a 1% aqueous solution of M. for 3-4 days in an incubator, then transferred for drying to 90% alcohol, also in an incubator, and finally to 95% alcohol. Silk, wound loosely on a glass plate, is sterilized for 5 minutes in boiling 1% aqueous solution of M., then transferred to 90-95% alcohol. The operative field is treated with a 1% solution of M. in 40% alcohol. M. does not cause skin burns; it also has the advantage over iodine in being cheaper; according to the pricing of state pharmacies, 100.0 of iodine tincture costs 1 ruble 42½ kopecks, while 100.0 of M. costs 36 kopecks. The question of the possibility of completely replacing iodine tincture with a solution of M. should be considered as still only in the stage of study and requiring further verification both experimental and clinical—this especially concerns the disinfection of the operative field. With widespread use in the operating room, the dye stains linen, the floor, and the surgeon's hands and is washed off with great difficulty, from linen—by prolonged boiling, from hands—with hydrogen peroxide and alcohol. There are also attempts to use M. as an antiseptic in ophthalmic practice (blepharitis) and in dermatology (sycosis of the beard).