§ 320. Commissioner of taxation and finance custodian of fund. The commissioner of taxation and finance shall be the custodian of the special fund for workmen's compensation for civil defense volunteers and all disbursements for compensation therefrom shall be paid by him upon drafts signed by the chairman or those authorized by the chairman for that purpose. The commissioner of taxation and finance shall give a separate and additional bond in an amount to be fixed by and with sureties approved by the state comptroller conditioned for the faithful performance of his duty as custodian of the fund. The commissioner of taxation and finance may deposit any portion of the fund not needed for immediate use, in the manner and subject to all the provisions of law respecting the deposit of state funds by him. Interest earned by such portion of the fund deposited by the commissioner of taxation and finance shall be collected by him and placed to the credit of the fund.