Abstract
The study of the relation between the antiseptic action and the chemical constitution of synthetic dyes dates back to the period of Paul Ehrlich 1 who began with one group of dyes known as azo dyes, including trypan red, trypan blue and trypan violet. The other group of dyes consisted of basic tryphenyl-methane dyes, including parafuchsin, methyl violet, pyronin G and other similar substances, known as neurotrophic dyes because of their ability to stain nerve tissue.
McIntosh and Fildes 2 reported that arsenic could not be found in the brain tissue, due to a lack of affinity between the brain substances and the inability on the part of the drugs to penetrate into the brain. In vitro experiments show that this is purely a question of physical penetration. The same authors 3 classified the dyes as, (1) those which stain the central nervous system, and (2) those which do not stain the central nervous system. They conclude that these variations were dependent upon the question of solubility. The subject further resolved itself into the fact that neurotropic substances are lipotropic, and before a substance can penetrate into a cell it must be solu'ble in the cell membrane or possess a distinct osmosis.
Kalberlah 4 decided that there was a distinct increase in the arsenic content when dye was used.
Smith and Waddell 5 increased the permeability of the choroid plexus to arsphenamine with methyl violet. Their conclusion is that methyl violet when given intravenously does not increase the permeability.
Cornwall and Myers 6 showed that arsenic actually penetrated the cord and the brain. These experiments are being repeated with the idea of checking up the effect of transfusion just previous to the sacrificing of the animal.
Fordyce and Myers 7 studied the action of salvarsan, neosalvarsan, silver salvarsan and tryparsamide on penetration of arsenic into the central nervous system in general paresis and cerebrospinal syphilis.
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