Repeated intravenous injections of egg albumin in rabbits produced small antigen-excess complexes and severe glomerulonephritis. Immunoglobulins and complement in the glomeruli were not clearly demonstrated by immunofluorescence; deposits were found to be sparse by electron microscopy. This study demonstrates that soluble immune complexes are responsible for the glomerular reaction. The apparent absence of deposits is thus not sufficient to exclude an immune complex pathogenesis.