Section 18. Estates may be specially exempted from sale.

It shall be competent to the Collector or other Officer as aforesaid, at any time before the sale of an estate or share of an estate shall have commenced, to exempt such estate or share from sale ; and in like manner it shall be competent to the Commissioner of Revenue, at any time before the sale of an estate or share of an estate shall have commenced, to exempt such estate or share from sale, by a special order to the Collector or other Officer as aforesaid to that effect in each case; and no such sale shall be legal if held after the receipt of such order of exemption. Proviso.--Provided, however, and it is hereby enacted, that the Collector or other Officer as aforesaid or the Commissioner shall duly record in a proceeding the teas on for granting such exemption ; provided also that an order for exemption so issued by the Commissioner shall not affect the legality of a sale which may have taken place before the receipt by the Collector or other Officer as aforesaid of the order of exemption.