A surgical instrument for use in connection with a pneumatically powered tool having a firing mechanism operably supported therein that is movable between an unactuated position and an actuated position. In various embodiments, a drive system operably communicates with the pneumatically powered tool and is configured to selectively apply at least a drive system generated firing motion to the firing mechanism of the pneumatically powered tool to cause the firing mechanism to move from the unactuated position to the actuated position in response to a flow of gas from a source of gas fluidically coupled to said drive system. A retraction member communicates with the drive system to enable a manually generated retraction motion to be applied thereto to manually move the firing mechanism in a distal direction from the actuated position to the unactuated position. [IN-KOL-2007-00999A]
