HOBER: THE MEMBRANE THEORY 383 



procedure has been applied to single frog muscle fibers by Gerard, 

 Carlson, and Graham.^ 



B. The Inorganic Anions 



The colloidal behavior of the physiological membranes, further, is 

 brought into evidence by the effect of the inorganic anions. In gen- 

 eral, with regard to their role in physiology, the anions are less powerful 

 than the cations. This is due to the prevalent negative charge of the 

 colloidal aggregates, which repel the anions. Locally applied to nerve 

 or muscle, the resting potential reveals the following anion series: thio- 

 cyanide, iodide, bromide and chloride, sulfate, with thiocyanide ion 

 producing a positive pole. In other words, a reversed injury potential 

 occurs as a consequence of the anion adsorption on the membrane, 

 which is greatest with thiocyanide, smallest with sulfate. This re- 

 versal is an important point to be kept in mind for later discussion. 

 However, after some lapse of time or after applying the salts in stronger 

 solution, the anion series is reversed, thiocyanide and iodide forming 

 a negative pole, thus resembling the effect of potassium ion. This, 

 again, is significant, as due to a loosening, softening, and subsequent 

 disintegrating action upon the hydrophilic colloidal membrane.^' ^ 



C. Organic Anions 



These effects are related to those of a large group of organic anions: 

 for instance, those of higher fatty acids starting with the 8-carbon atom 

 chain, i.e., caprylic acid. These ions have a nonpolar-polar structure, 

 the nonpolar, or organophilic and hydrophobic, part of the anion, 

 mainly due to the adsorption affinities of the alkyl radicals, attaching to 

 the organic material, e.g., to the particles of a Langmuir surface film 

 of protein; the other polar or hydrophilic part, due to the carboxyl 

 radicals with their cloud of water dipoles, anchoring in the water. 

 It appears that a pull towards the water can be exhibited upon the 

 organic material. The pull is stronger or weaker, corresponding to the 

 relative hydroaffinity, so that colloidal particles composed of a variety 

 of molecules, hke hemoglobin (which means, hem plus globin), visual 

 purple, or chloroplastin, can be torn to pieces, a process termed de- 

 naturation, solubilization, or detergency. On the other hand, coiled 

 peptide chains can be uncoiled, and organic architectures of great com- 

 plexity, such as a plasma membrane, can be loosened by the adsorptive 

 pull, which has the effect of abolishing reversibly the selective ion 

 permeability of the membrane and starting irreversible cytolysis.^ 

 For example, sodium caprylate is applied locally to a muscle. The re- 



