The Legislature may by law authorize the creation of county-wide Hospital Districts in counties having a population in excess of 190,000 and in Galveston County, with power to issue bonds for the purchase, acquisition, construction, maintenance and operation of any county owned hospital, or where the hospital system is jointly operated by a county and city within the county, and to provide for the transfer to the county-wide Hospital District of the title to any land, buildings or equipment, jointly or separately owned, and for the assumption by the district of any outstanding bonded indebtedness theretofore issued by any county or city for the establishment of hospitals or hospital facilities; to levy a tax not to exceed seventy-five ($ .75) cents on the One Hundred ($100.00) Dollars valuation of all taxable property within such district, provided, however, that such district shall be approved at an election held for that purpose, and that only qualified voters in such county shall vote therein; provided further, that such Hospital District shall assume full responsibility for providing medical and hospital care to needy inhabitants of the county, and thereafter such county and cities therein shall not levy any other tax for hospital purposes; and provided further that should such Hospital District construct, maintain and support a hospital or hospital system, that the same shall never become a charge against the State of Texas, nor shall any direct appropriation ever be made by the Legislature for the construction, maintenance or improvement of the said hospital or hospitals.