Notwithstanding any other provision of law, none of the establishments or agencies named in subsection (b) of this section shall, after June 30, 1937, incur any obligations for administrative expenses, except pursuant to an annual appropriation specifically therefor, nor shall any such establishment or agency continue to function after said date unless established by or pursuant to law: Provided, That nothing contained in this section shall be construed to extend the period during which any such establishment or agency heretofore has been authorized by law to function.