Upon the appointment of a board of trustees for any institution acquired by the Commonwealth from any county, city or institution district under the provisions of act number twenty-one, approved the twenty-ninth day of September, one thousand nine hundred thirty-eight, the existing employes of the institution shall acquire the same status as that of employes in State institutions under the supervision of the Department of Welfare and the management of a board of trustees.
50 P.S. § 1059