SINCE the advent of electrophoresis in a supporting medium for the separation of proteins, many new techniques have been developed to produce constant, better fractionation to enhance the quantitative results. In spite of the multiplicity of techniques, no single one has been demonstrated to combine simplicity, reproducibility, high resolving power, and reduction of sample amount without direct or indirect interactions with the medium. Many of the technical difficulties encountered can be traced to the supporting medium. Therefore, agar gel merits special consideration because of its virtually nonexistent adsorption of proteins, its homogeneity, its good optical properties in a wet or dry state, and its qualities which allow for easy preparation. Electrophoretic protein separation in an agar medium was first utilized by Gordon1and subsequently modified for immunoelectrophoresis by Grabar and Williams.2Recently Wieme3-5has described a new electrophoretic technique in agar gel that provides higher resolving