The Board is authorized to accept gifts of money made unconditionally by will or otherwise for the carrying out of any of the functions under this chapter. A conditional gift of money made by will or otherwise for such purposes may be accepted and used in accordance with its conditions, but no such gift shall be accepted which is conditioned upon any expenditure not to be met therefrom or from income thereof unless the Board determines that supplementation of such gift from the fees it may expend pursuant to sections 1755 and 1756 of this title or from any funds appropriated pursuant to