I 3 3 LECITHAN COMPOUNDS. Koch' has lately described the 'preparation of various compounds with lecithans, but it is uncertain whether these compounds are colloidal mixtures, mechanical mixtures or true chemical compounds. It seemed of interest to study the behavior of these substances in ether solution, when subjected to dialysis in rubber bags suspended in ether. The preparations used in these experiments were made according to the method described by Koch. For the dialysis tests the

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... of the lecithan compounds were evaporated to dryness a t 38" and the residues ground up with ether. The extracts were filtered and the filtrates placed inside of rubber bags and dialyzed against ether for thirty-seven days. The dialysates were tested every week to see if the substance combined with the lecithan diffused. Compounds of lecithin with glucose, lactic acid, strychnin, digitonin, salicin, urea, creatin, creatinin and caffein were prepared. It was found that the glucose and lactic acid dialyzed completely, the strychnin, digitonin and salicin dialyzed partially, while urea, creatin, creatinin and caffein did not dialyze a t all. (607) IKoch, Journ. Pharm. and Ex@. Ther., 1911, ii, p. 239.