And the Secretary of the Treasury is hereby authorized to receive and cancel any United States coupon bonds, and to issue in lieu thereof registered bonds of like amount, bearing a like rate of interest, and having the same time to run; and the deposit of bonds shall be, by every association, increased as its capital may be paid up or increased, so that every association shall at all times have on deposit with the Treasurer registered United States bonds to the amount of at least one-third of its capital stock actually paid in :