THE ACCUMULATION OF ELECTROLYTES : III. BEHAVIOR OF SODIUM, POTASSIUM, AND AMMONIUM IN VALONIA

When 0.001 M NH₄Cl is added to sea water containing Valonia macrophysa there seems to be a rapid penetration of undissociated NH₃ (or NH₄OH) which raises the pH value of the sap so that the thermodynamic potential of KOH becomes greater inside than outside and in consequence K leaves the cell: NaOH continues to go in because its thermodynamic potential is greater outside than inside.

NH₄Cl accumulates, reaching a much higher concentration inside than outside. This might be explained on the ground that NH₃, after entering, combines with a weak organic acid produced in the cell whose anion is exchanged for the Cl^- of the sea water, or (more probably) the organic acid is exchanged for HCl.