When the estimates for supplies for the institutions under the control of the supervising department have been certified and revised by the supervising department and bids for the supplies enumerated and described therein have been received and contracts for furnishing the supplies have been let by the office of management and budget, a copy of such revised estimates and the contract for furnishing the supplies enumerated and described in such revised    estimates, duly certified, must be sent to the institution and another copy must be sent to the supervising department having control of such institution.