That section 3 of Article XI of the, constitution be amended to read: (Article XI) Section 3. Cities and villages organized pursuant to state law * * * are hereby empowered, to determine their local affairs and government, subject only to this constitution and to such enactments of the legislature of state-wide concern as shall with uniformity affect every city or every village. The method of such determination shall be prescribed by the legislature. * * * No county, city, town, village, school district, or other municipal corporations hall be allowed to become indebted in any manner or for any purpose to any amount, including existing indebtedness, in the aggregate exceeding five per centum on the value of the taxable property therein, to be ascertained by the last assessment for state and county taxes previous to the incurring of such indebtedness. Any county, city, town, village, school district, or other municipal corporation incurring any indebtedness as aforesaid, shall, before or at the time of doing so, provide for the collection of a direct annual tax sufficient to pay the Interest on such debt as it falls due, and also to pay and discharge the principal thereof within twenty years from the time of contracting the same; except that when such indebtedness is Incurred in the acquisition of lands by cities, or by counties having a population of one hundred fifty thousand or over, for public, municipal purposes , or for the permanent Improvement thereof, the city or county Incurring the same shall, before or at the time of so doing, provide for the collection of a direct annual tax sufficient to pay the interest on such debt as it falls due, and also to pay and discharge the principal thereof within a period not exceeding fifty years from the time of contracting the same.