Medical and dental manpower, compulsory smallpox vaccination, and American University incorporation : hearing before the Subcommittee on Public Health, Education, Welfare, and Safety of the Committee on the District of Columbia, United States Senate, Ninety-third Congress, second session on S. 2730, to extend for 3 years the District of Columbia Medical and Dental Manpower Act of 1970 : H.R. 8747, to repeal section 274 of the Revised statutes of the United States relating to the District of Columbia, requiring compulsory vaccination against smallpox for public school students : S. 3389, to amend the act entitled "An act to incorporate the American University," approved February 24, 1893, May 1, 1974.