MICRURGICAL STUDIES IN CELL PHYSIOLOGY : III. THE ACTION OF CO(2)AND SOME SALTS OF NA, CA, AND K ON THE PROTOPLASM OF AMŒBA DUBIA.

I. Plasmalemma. 1. Of the salts used in these experiments the anions have only a modifying effect on the cations. The dispersive action of Na and, to a lesser extent, of K, predominates. Borate increases the toxicity of Na and acetate decreases it. 2. CO(2) and carbonates dissolve the plasmalemma readily. 3. Na lactate tends to dissolve the surface especially when brought into contact with it from the interior by injection. Lactate antagonizes the stimulating effect of Ca on the plasmalemma. II. The Internal Protoplasm. 4. Acid phosphate of Na and K, when injected, causes a membrane to form around the granular endoplasm within the ameba. 5. Na borate increases the toxicity of Na inside the cell. 6. Bubbles of CO(2), injected into the cell, cause an increase of fluidity of the internal protoplasm. These bubbles shrink and disappear from the cell more readily than air bubbles. 7. The anions modify the typical cation effect. Carbonates accentuate the liquefying and solvent action of Na. Phosphates prevent a complete rounding of the ameba caused by Na. Lactate inhibits the solidification and pinching off effect caused by Ca. III. Physiological Significance of Salts. 8. The buffer salts can be injected in high concentrations without toxic effects but amebæ can be immersed in them only in very dilute solutions without injury. 9. The inhibiting action of lactate and the dispersive effect of CO(2), carbonates, and lactate on the plasma membrane, must be of importance in a consideration of the functions of the organism and perhaps in the production of pathological changes.