And it is hereby enacted, that all sales of which the purchase money has been paid up as prescribed in Section XVI. of this Act, and against which no appeal shall have been preferred, shall be final and conclusive at noon of the thirtieth day from the day of sale, reckoning the said day of sale, as the first of the said thirty days. And sales against which an appeal may have been preferred, and the appeal dismissed by the Commissioner, shall be final and conclusive from the date of such dismissal, if more than thirty days from the day of sale, or if less, then at noon of the thirtieth day as above provided.