The certified copy of the complaint offered in evidence by the defendant was competent to contradict the witness Sprague. The fact that, on cross-examination, the witness admitted that he had signed and sworn to such a complaint, and identified the copy as a true copy, rendered the contents of the complaint admissible, so far as they tended to contradict the witness, and the contents of the complaint were not offered in evidence during the cross-examination. The defendant, when putting in his defence, offered this copy in evidence. To what extent it tended to contradict the witness, and what weight it was entitled to, in view of the whole evidence and the contentions of the government, we do not know; it plainly had some tendency to contradict the witness, and its rejection may have prejudiced the defendant. Exceptions sustained.