By: David Rilley-Harris, Curator, DITSONG: National Museum of Military History (DNMMH)   A German soldier, not cowardly, but incapacitated (Picture: https://daliennation.wordpress.com/2017/11/18/medical-history-shell-shock/).   Before the First World War (1914-1918) combat had revolved largely around cavalry and infantry tactics, but by the beginning of the twentieth