In the civil law. The unlawful forcing of another by threats of violence to give something of value. It differs from robbery, in this: That in robbery the thing Is taken by force, while in concussion it is obtained by threatened violence. Heinec. Elem. f 1071. In medical jurisprudence. Concussion of the brain la a jarring of the brain substance, by a fall, blow, or other external injury, without laceration of its tissue, or with only microscopical laceration. Maynard v. Railroad Co., 43 Or. 63, 72 Pac 590.