768 TRIVALENT AND TETRAVALENT IONS 



3. This is in harmony with the fact shown in a preceding paper 

 that salts with trivalent or tetravalent ions can cause the ioniza- 

 tion of proteins at its isoelectric point and thus give rise to a mem- 

 brane potential between micellae of isoelectric protein and sur- 

 rounding aqueous solution, while the above mentioned salts with 

 divalent and monovalent ions have apparently no such effect. 



