The county commission must audit all claims against the county, and every claim or such part thereof as is allowed must be registered in a book kept for that purpose and the chairman of the county commission must give the claimant a warrant on the treasury for the amount so allowed, but bonds and interest coupons evidencing interest on such bonds lawfully issued by the county shall not be required to be registered or to be proved nor shall warrants be required to issue therefor, but, in addition to all other privileges, shall be held to enjoy all the privileges of registered warrants from the date of their lawful issue and shall be held to be allowed claims from the date of their lawful issue.