That Act No. 200 of the Public Acts of 1891, entitled "An act to provide for the assessment of property and the levy of taxes thereon, and for the collection of taxes heretofore and hereafter levied, and to repeal Act No. 195 of the Session Laws of 1889, except as provided in this act, and all other acts and parts of acts in anywise contravening any of the provisions of this act," approved July 7th, 1891, and all other acts and parts of acts in anywise contravening any of the provisions of this act, be and the same is hereby repealed: Provided, That such repeal shall not destroy or affect any rights which may have accrued or may hereafter accrue under such acts or parts of acts while the same were in force.