§ 349. County or part-county boards of health; other health functions; hospitals and laboratories. In any county in which a county health district has been or is hereafter established, the boundaries of which are coterminous with the county, the board of supervisors shall have power to abolish the board of managers of the county tuberculosis hospital, or of the county public general hospital, or of the county laboratory, and, if so abolished, shall confer all the powers and duties of any or all of such boards of managers upon the county board of health.