[Introduction to the use of selective electrodes in clinical biology].

The relatively recent distribution of apparati which allow cation measurement by electrometry presents the biologist with a certain number of difficulties inherent to this methodology. A review of the principles of electrochemistry, limited to the facts necessary to master use of these apparati and avoiding the dissipated effort inevitably incurred by consulting treatises, is of an evident practicality. The points concerning, in particular, application in clinical biology have been treated in detail, whether they involved the definition of direct and indirect potentiometries, or the concepts of activity and of concentration, or the explanation of the actual problems posed by the plasma/plasmatic water difference and by electrometry/flame photometry comparison measurement. A survey of the different types of standard electrodes in biology completes this works.