NOLLE PROSEQUI is where a plaintiff in an action does not declare in a reasonable time, in which case it is usual for the defendant's attorney to enter a rule for the plaintiff to declare, after which a non prosequitur may be entered. A nolle prosequi is esteemed a voluntary confession that the plaintiff has no cause of action; and therefore if a plaintiff enters his nolle prosequi, he may be amerced; but if an informer cause the same to be entered, the defendant may have costs.