As monopoly investigation opened. Washington, D.C., Dec. 1. First witness before the Joint Committee Investigating Monopolies today was Isador Lubin, left, Commissioner of Labor Statistics, U.S. Dept. of Labor, who is pictured with Senator Joseph C. O'Mahoney, Co-chairman of the Committee. Lubin told the Committee that American wage earners have lost $119,000,000,000 during nine years of unemployment