Expenditure and disbursement of special funds.
Section 28
SEC. 28. Expenditure and disbursement of special funds.—No expenditure shall be incurred, nor any disbursement made, out of the appropriations authorized in this Act from special, revolving and trust funds and from. receipts automatically appropriated which will exceed at any one time either the fund itself or the cash in the National Treasury pertaining to such fund, except when, in the opinion of the President, such expenditure or disbursement is required by the exigency of the service, and sufficient income or receipts are expected to accrue to such funds to cover said expenditures or disbursement, in which case the necessary amount may be advanced from the general fund.