Remarkable changes are brought about by KOH in transforming negative cells of Nitella (showing dilute solution negative with KOH) to positive cells (showing dilute solution positive with KOH). NaOH is less effective as a transforming agent.
This might be explained on the ground that the protoplasm contains an acid (possibly a fatty acid) which makes the cell negative and which is dissolved out more rapidly by KOH than by NaOH, as happens with the fatty acids in ordinary soaps.
Part of a negative cell can be changed to positive by exposure to KOH while the untreated portion remains negative.
After exposure to KOH the potential the protoplasm has when in contact with NaCl may increase. At the same time there may be an increase in the potassium effect; i.e., in the change of P.D. in a positive direction observed when 0.01 M KCl is replaced by 0.01 M NaCl.
In some cases the order of ionic mobilities is uK > vOH > uNa. This shows that the protoplasmic surface cannot be a pore system: for in such a system all cations must have greater mobilities than all anions or vice versa.