The proceeds derived from the sale of the bonds herein authorized shall be deposited to the credit of the board of county commissioners in a bank, banks or other depositories designated by the board and kept in a separate fund and used solely for the purpose for which the bonds are authorized. The board is authorized to make all contracts and execute all instruments which in its discretion may be deemed necessary or advisable to provide for constructing, furnishing and equipping of the home for the aged addition, and to provide for the manner of disbursement of the funds for such purposes. Nothing contained in this act shall be construed as placing in the county general fund or other county fund any money collected under this act or requiring such action.