The system of measures taken by government with ref- erence to the direct prevention of crime. It generally consists in obliging those persons whom there Is probable ground to suspect of future misbehavior to give full assurance to the public that such offense as is apprehended shall not happen, by finding pledges or securities to keep the peace, or for their good behavior. See 4 Bl. Comm. 251; 4 Steph. Comm. 290.