as used with reference to the doctrine of self-defense in homicide, means such overt actual demonstration, by conduct and acts, of a design to take life or do some great personal injury, as would make the killing apparently necessary to selfpreservation. Evans v. State, 44 Miss. 773; Stoneman v. Com.. 25 Grat. (Va.) 890; Leigh v. People, 113 111. 379.