In any county in which a special county tax is levied and collected, pursuant to the provisions of any amendment to the constitution heretofore adopted, for the purpose of acquiring, constructing, equipping, operating and maintaining public hospitals, public clinics, public health centers and related public health facilities of any kind, or for any one or more of the purposes included within the meaning of the term “public hospital purposes,” the county commission of the county is hereby authorized to appropriate so much of the proceeds of such tax as may be necessary for the purpose of carrying out the provisions of this article; provided, that if any portion of the proceeds of such tax has been heretofore pledged to the payment of any bonds, warrants, notes or other obligations or evidences of indebtedness, such portion of the proceeds of the tax as shall have been so pledged shall not be used for any purpose except in payment of such bonds, warrants, notes or other obligations or evidences of indebtedness. The county commission of the county is also authorized to appropriate, out of any funds in the county treasury not otherwise appropriated, such amounts as may be necessary in carrying out the provisions of this article.