References(2) Among the methods of the paper chromatography of digitalis glycosides, that of the Svendsen and Jensen's is widely used. It uses the mixture of chloroform, methyl alcohol and water for development and trichloroacetic acid for producing fluorescence. Our experiment has shown that there is a kind of digitoxin which does not produce fluorescence with trichloroacetic acid.Digitoxin made by Merck Co. of Germany (Dm), when developed on filter paper strip with the mixture of chloroform, methyl alcohol and water and heated with trichloroacetic acid, evidently produced two fluorescent spots with Rf values characteristic of digitoxin and gitoxin, in ultra-violet light. But digitoxin made by Rosenthal-Bercow Co. of the U.S.A. (Dr), when treated by the same method, produced only one fluorescent spot of gitoxin and none of digitoxin even if a large quantity of material was used. If, in that case, other reagent, for example Raymond's, was used, digitoxin contained in Dr was found on the spot of filter paper that had the same Rf value as that of Dm.As both Dm and Dr contained some quantity of gitoxin, they were purified by the chromatography. After materials dissolved in ethyl acetate containing mehtyl alcohol by 0.5 volume per cent, were passed through the column plugged with silica gel, the portions positive in the Keller-Kiliani's reaction were gathered-from filtrates. In these substances could no gitoxin spot be found by the paper chromatography. Therefore these substances were considered to be almost purified.These two kinds of purified digitoxin were alike in several chemical reactions and had no appreciable difference in biological action on the frog heart. However, purified Dr did not produce fluorescence while purified Dm did.As a result of these studies, it has been shown that there are two kinds of digitoxin and that it is not desirable to depend only upon the method of Svendsen and Jensen's in the paper chromatography of digitalis glycosides.
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