The rate of penetration and the solubility of H, O, N, NH(3), H(2)O, HCl gas, CO(2), formic, acetic, chloracetic, dichloracetic acid, glycerol, phenol and mercury bichloride in dry collodion membranes have been measured. The rate of penetration of H and CO(2) is the same whether the membrane and gas are dry or whether the membrane is immersed in water. The solubility of CO(2), acetic acid, phen...

In preceding communications t, 2 we were led to the conclusion that the electrochemical activity of collodion membranes, as manifested by concentration potentials, etc., is due principally to acidic impurities. Accordingly, different brands of collodion differ widely as to their activity, the purer brands being less active. The impure (but active) foreign brands of collodion, heretofore general...

Sanarelli (1891) is believed to have been the first to employ collodion sacs in animal experimentation. Subsequently, sacs of different types have been used in various in vivo experiments by a number of investigators (see bibliography). Alcohol-ether collodion was employed in each case for the preparation of the semipermeable membranes. In order to withstand the distorting effect of the intesti...

The preceding paper 1 of this series describes the preparation of "megapermselective" collodion membranes which are extremely impermeable to anions, but at the same time are very permeable to univalent cations. The purpose of the present paper is to describe the preparation and the properties of analogous electropositive "megapermselecfive" membranes which are very impermeable to cations, but a...

Previous publications 1, ~ in this series have dealt with the preparation and electrochemical properties of the activated (electronegative) collodion membrane. The activation consisted of an oxidation of the nitrocellulose, a process which caused an increase in the number of dissociable groups in the pores of the membrane. Such membranes show more pronounced effects than similar untreated membr...

1. The cataphoretic P.D. of suspended particles is assumed to be due to an excess in the concentration of one kind of a pair of oppositely charged ions in the film of water enveloping the particles and this excess is generally ascribed to a preferential adsorption of this kind of ions by the particle. The term adsorption fails, however, to distinguish between the two kinds of forces which can b...

Previous publications 1, ~ in this series have dealt with the preparation and electrochemical properties of the activated (electronegative) collodion membrane. The activation consisted of an oxidation of the nitrocellulose, a process which caused an increase in the number of dissociable groups in the pores of the membrane. Such membranes show more pronounced effects than similar untreated membr...

The electrochemical properties of collodion membranes are known to vary greatly with the nature of the collodion preparation used, more acid preparations yielding membranes of higher electrochemical activity, x-s The assumption has always been made, tacitly or expressly, that the thickness of the membrane is of no influence. Thus, it has been generally assumed that the characteristic concentrat...

Cultures of rat cerebellum grown on glass coverslips coated first with collodion and then collagen are fixed in glutaraldehyde to which ruthenium red has been added. After fixation, the collodion comes off the glass coverslips and the 3 layers: collodion-collagen-culture are handled as one piece. Following immersion in glycerol, selected areas are cut from the piece; the excised areas are a lit...