Abstract
Brinkman and Szent-Györgyi 1 report that various capillary active substances, alkaloids 2 and purine bases (sodium oleate, sodium linoleate, sodium glycocholate, digitonin, Witte's peptone, atropine, pilocarpine, caffeine, strychnine, quinine and morphine) cause permeability of collodion membranes to hemoglobin. Rosenthal 3 states that sodium taurocholate possesses the property of increasing the degree of permeability of semi-permeable collodion membranes to dyestuffs. Clausen has shown the presence of some capillary active substance in blood serum 4 and urine of patients suffering from parenchymatous nephritis (nephrosis) which greatly lowers the surface tension, and reports that the addition of blood serum, urine, or, a water solution of the alcohol soluble portion of the colloidal residue from evaporated urine of these patients, will cause collodion membrane to become permeable to proteins. 5 Grollman 6 finds that the collodion sacs used in his investigation were not rendered permeable to hemoglobin by use of bile salts, sodium oleate, lanthanum chloride, acid or alkali.
The permeability of collodion membranes may be varied by many factors in their preparation and subsequent treatment. It has been shown to depend upon the thickness and the ratio of wet to dry weight of the finished membrane, or, according to Brown, 7 upon the alcoholic index of the membrane.
Membranes were prepared in 2 × 17 cm. test-tubes, using 5 cc. of a solution of 2 gr. nitro cellulose in 100 cc. of alcohol-ether mixture. After drying, the membranes were graded according to the method of Brown. Solutions of various substances were placed in the membranes and the membranes then placed in distilled water, the rate of diffusion of the substance across the membrane king taken as an index of the permeability of the membrane, when calculated as the ratio of the concentration outside divided by the concentration inside the membrane at various times.
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