Abstract: A planar rigid support for electrophoresis comprising a cellulose acetate strip or the like can bear on two fixed highly spongy plates which are placed in the electrolytic bath so as to emerge from the upper level thereof. In particular, the support may comprise a resilient strip-holder, in which the fastening occurs by providing in the strip two series of holes which are inserted in stakes provided on two opposite sides of the strip-holder. The several steps for the analysis of total and fractional proteins are obtained displacing each support and other fittings by a handling means preferably provided with magnetic pliers cooperating with iron portions provided on each support or fitting to be handled.