Institutio Oratoria

For just as in a set speech we usually collect detached arguments which in themselves seem innocuous to the accused, but taken together prove the case against him, so we must ask the reluctant witness a number of questions relative to acts antecedent or subsequent to the case, places, dates, persons, etcetera, with a view to luring him into some reply which will force him to make the admissions which we desire or to contradict his previous evidence.