In all cases where lands have been or may hereafter be sold for delinquent taxes, penalty, interest and costs and a certificate of purchase has been or may hereafter be issued it is hereby made the duty of such purchaser, his heirs or assigns, to cause a deed to be executed and placed on record in the proper county within four years from the date of said sale; provided, that on failure of said purchaser, his heirs or assigns so to do, then and in that case the amount due such purchaser shall cease to be a lien on said lands so purchased as herein provided.

(RSMo 1939 § 11137)