"Napoleon went so far, however, in 1858, as to order his SB guns rifled, under the bastard system known as the "Lahitte System," which continued in general use in France until 1870" in The Long Arm of Lee by Jennings Cropper Wise, Gary W. Gallagher p.30 [1]
"...the introduction by the French army of the Beaulieu 4-pounder rifled field-gun in 1858: the new artillery, though much more accurate and long-ranged than the smoothbore 'canon-obusier' it replaced (which, incidentally, was the most prevalent artillery piece of the US Civil War), was not suited to firing anti-personnel case-shot (which, in French, is called 'mitraille')." in The Mitrailleuse by Dr. Patrick Marder Military History OnlineArchived 2008-12-23 at the Wayback Machine
"...the introduction by the French army of the Beaulieu 4-pounder rifled field-gun in 1858: the new artillery, though much more accurate and long-ranged than the smoothbore 'canon-obusier' it replaced (which, incidentally, was the most prevalent artillery piece of the US Civil War), was not suited to firing anti-personnel case-shot (which, in French, is called 'mitraille')." in The Mitrailleuse by Dr. Patrick Marder Military History OnlineArchived 2008-12-23 at the Wayback Machine