Charles E. Ryan served with the corps as a dresser and assistant surgeon and in 1896 published an account of his time with the unit. The unit left Paris on 28 August by train for the battlefield of Carignan but was delayed as Prussian forces had captured the railway line. The ambulance was held at Sedan railway station where its personnel encountered the French Emperor Napoleon III and the retreating survivors of the Battle of Beaumont. The ambulance attempted to move towards the front by road but found it was caught between the two armies and returned to Sedan. Twelve men of the ambulance treated more than 600 wounded of the subsequent Battle of Sedan (1–2 September) from a hospital that periodically came under shellfire. The remaining four medical staff ran a secondary hospital at Balan which treated the wounded of a battle fought there on 31 August and those of the 1 September Battle of Bazeilles. With the ambulance at Sedan was Marcus Beck who reported that the French army surgeons had not adopted the anti-septic measures advocated by his father's cousin Joseph Lister.