Causes of railroad amalgamation, 34.—Corporate control of railroads defined, 36.—Control through lease, 38.—Control through ownership of securities, 39.—Joint control, 41.—Virtual control, 44.— Inactive corporations, 45.—Minority holdings of railroad securities, 46.—Holding companies: trust companies, intermediate holding companies, land and improvement companies, 50.—Entanglements of the intercorporate relationship, 54.—Holding companies at the head of systems: Atlantic Coast Line Company, Reading Company, Rock Island Company, 58.—Purpose of the holding company and reasons for public opposition, 61.—Suggested remedies, 64.