Abstract: Prior to measuring the concentration of a nonelectrolyte in an electrolyte solution, the electric conductivity of a mixed solution containing electrolytes and the nonelectrolyte is previously measured so as to determine the correlation between the electric conductivity and the concentration of the nonelectrolyte as to the same system. The concentration of the nonelectrolyte in the mixed solution can be determined from the electric conductivity obtained by measuring the mixed solution, based on the correlation.

Abstract: Prior to measuring the concentration of a nonelectrolyte in an electrolyte solution, the electric conductivity of a mixed solution containing electrolytes and the nonelectrolyte is previously measured so as to determine the correlation between the electric conductivity and the concentration of the nonelectrolyte as to the same system. The concentration of the nonelectrolyte in the mixed solution can be determined from the electric conductivity obtained by measuring the mixed solution, based on the correlation.

Abstract: Blood guided out of the artery of a patient by a blood pump is introduced into an arterial inlet of a blood flow direction changeover device, and it is then guided from the outlet of the changeover device to a dialzyer through an inlet thereof. The blood then leaves an outlet of the dialyzer, enters the blood flow path changeover device, leaves a venous outlet of the changeover device and returns into the vein of the patient. The dialytic liquid, on the other hand, leaves a dialytic liquid outlet, passes through a dialytic liquid flow direction changeover device and is finally discharged through a dialytic liquid outlet. Then, the respective changeover devices are changed over to reverse the respective flows. This is intermittently repeated. Thus, blood coagulation can be inhibited or prevented.