EobiNSON, C. J.
In September, 1889, the plaintiff was in the employment of the defendant as brakeman of a freight train. While attempting, in the line of his employment, to couple together certain cars, he was caught by a moving car, and so injured that he lost his right foot and a part of his left heel. The accident occurred at Washington in this state. The train with which the plaintiff was working had been separated into two parts. The forward part contained ten or more cars, and its rear end was backed from the main track onto a side track for the purpose of taking out certain cars which stood on it. Eách of the two cars which were to be coupled together had a coupling link, one of which had to be removed before the coupling could be made. The link in the stationary car was not removable, and the plaintiff approached the other car to remove the link and set the pin to make the coupling, when the car backed against him, his foot was caught by a brake-beam, ' and he was thrown down, and, being unable to free himself in time to prevent it, received the injuries in question. The plaintiff in his original petition stated that, when he observed that there was a link in each car, he signaled the engineer to stop, and,' believing that the signal would be obeyed, he stepped in to remove the link, but the engineer did not obey the signal and did not stop; that .the defendant was negligent in not obeying any signal to stop, and in not stopping the train. Other grounds of negligence were also alleged, but need not *313be stated. The petition was verified by the plaintiff. After the ease was reached for trial, and during the trial, several amendments to the petition were filed. The third of these, in effect, alleged that, if the engineer stopped the train, he negligently, and without a signal so to do, started it back, thereby causing the injuries of which the plaintiff complains. Near the close of the trial, the plaintiff filed another amendment to his petition, in which he alleged that the conductor carelessly and negligently ordered the train back, and that, in obedience to that order which was made without the knowledge of the plaintiff, and without any signal from him, while he was in a place of danger, the train was backed.
I. The appellee has filed a motion to strike from the files an amendment to the assignment of errors on 1. Practice in Supreme Court: assignment of errors: amendments. the ground that it was filed too late to be considered. It is permissible to file such , . ,, „ ,, „ . ,. amendments, m the furtherance of "justice. Stanley v. Barringer, 74 Iowa, 37. In this ease it does not appear that the submission in this court has been delayed, nor that the appellee has been in any manner prejudiced, by the filing of the amendment. His motion is therefore overruled.
II. It was claimed by the plaintiff on the trial, and his testimony tended to show, that, when he saw there 2. Evidence: witnesses: impeachment. was a link to be removed before the coupling could be made, he was standing -¶. on the mam track m sight ox the engineer, and eight or ten feet from the side track on which the cars were moving; that the engineer was looking at him when he gave the signal, and, when it was given, turned as though to obey it, and that he thinks the signal was obeyed, and that the cars stopped; also, that after the cars stopped they were negligently started towards him by the engineer without a signal, or in response to a signal negligently given by the con- ■ ductor. It was claimed by the defendant, and some of *314the evidence tended to show, that the plaintiff gave no signal to the engineer, and was not where the engineer could have seen a signal, had he given one; that no. signal to stop was given to the engineer until after the accident occurred, and that the train was not stopped until after that time; but that the conductor, seeing from his position on the main track what the plaintiff was doing, and that he was not in sight of the engineer, gave the latter a signal to back slowly. For the purpose of proving his theory of the case, the plaintiff called as a witness a man named Collins who was rear brakeman of the, train on which the plaintiff was employed when the accident occurred and was present at the time. Collins, however, testified, in effect, that Hall did not stand on the main track and give the engineer a signal to stop, but that he walked by the side of the car until he went in to change the link; that he did not see Hall give a signal until he went in to take out the link, and that while he was in there he gave the signal to back up; that the witness gave the signal to back up slowly just before Hall went in, but that while he was in to remove the link the witness gave no signal to the engineer to stop. The plaintiff then asked the witness if he did not state in writing as follows:
“State op Iowa, 1 “Wapello County, j ^ '
“I, Albert Collins, being duly sworn, on oath say that I was brakeman on the train by which H. L. Hall was injured. I was on the ground near to him, and, when he went in to fix the link ready for coupling, I signaled the engineer to stop. If he had stopped when the signal was given, Hall would not have been hurt. He did not stop.”
The witness at first denied that he had signed such a statement, but finally’ admitted that he had signed a paper for Hall. He was then asked if he did not tell Calvin McCoid, one of the attorneys for the plaintiff, at *315a time and place named, that he had signed the paper and would swear to what he had signed; and answered in the negative. He was then asked if he did not, in a. conversation specified, state to one Wright that he had given the engineer a signal to stop while Hall was fixing-the link; also, whether he did not tell Wright that Hall gave the signal to stop before he went in to the link, and that the witness gave another signal to stop after-Hall went in — and answered both questions in the negative. He was also asked if he did not sign a paper in the presence of Hall and others .named, and whether he-had not told Hall that he had given the engineer a. signal to stop, and answered in the negative. Wright was then called as a witness and permitted to testify that he had asked Collins if he saw the signal that Hall gave to the engineer, and that Collins answered that he had, and that he repeated it to the engineer. Wright also testified that he had told the plaintiff of the conversation. McCoid was called for the plaintiff and permitted to testify that Collins had said he gave the-engineer a signal, and that he would testify to the-statements contained in the paper he had signed. Hall was called, and testified that Collins read and signed the paper, and said he would swear to the statements it contained. The paper (omitting the sentence, “If he had stopped when the signal was given, Hall would, -not have been hurt.)” was then introduced in evidence. To all this evidence the defendant made due objection, and preserved exceptions to the rulings of the court in admitting it. It was admitted by the court “that plaintiff might show how he came to put said witnesses-on the stand;” and the jury were so instructed, and. told that they could consider it for no other purpose. The correctness of the rulings which permitted the-plaintiff to introduce evidence to contradict the testimony of Collins by proving the statements he had made, and the declaration he had signed at other times,, is now presented for our consideration.
*316It is the general rule that a party cannot impeach his own witness by introducing evidence which tends to show that he is unworthy of belief. Thorn v. Moore, 21 Iowa, 289; Clapp v. Peck, 55 Iowa, 272; 1 Greenleaf on Evidence, sec. 442. When a party is surprised by the testimony given by his witness, the attention of the latter may be called to the time and place where it is claimed he has made contrary statements. This is not for the purpose of laying the foundation for impeachment, but to probe and quicken the recollection of the witness, to give him an opportunity to correct his testimony, if it is erroneous, and to show that it has surprised the party who called' him. Humble v. Shoemaker, 70 Iowa, 226; Bullard v. Pearsall, 53 N. Y. 230; Hurley v. State, 21 N. E. Rep. (Ohio Sup.) 645; Cox v. Hayres, 55 Vt. 27; Melhuish v. Collier, 15 Adol. & E. (N. S.) 878; 1 Greenleaf on Evidence, sec. 444a; 1 Wharton on Evidence, sec. 549. The district court was within the rule in permitting the examination of Collins as to the statements he had made and the paper he had signed, but erred in permitting other witnesses to testify as to his statements, and in allowing the paper he signed to be introduced in evidence.
It is claimed that the error was cured by that portion of the charge of the court which directed the jury to consider such evidence only to ascertain why the plaintiff called Collins to the stand as a witness. It was said in Potter v. Ry. Co., 46 Iowa, 404, that: ‘ ‘Where there has been error, a presumption of prejudice arises; and, if the record fails to satisfy us that no prejudice has been caused, then such error cannot be disregarded. This should not be left in serious doubt. ” That rule has since been approved, and is in harmony with the settled practice of this court. See Strobel v. Moser, 70 Iowa, 126; George v. Ry. Co., 53 Iowa, 504, The mere fact that the charge of the court was designed to restrict the evidence offered to a legitimate purpose does not show that no prejudice resulted. Errors may *317be so serious that instructions to the jury will not cure them. Martin v. Orndorff, 22 Iowa, 505.
If the plaintiff attempted to take out the link and make the coupling while the car was in motion, he did so in violation of a rule of the defendant of which he had knowledge. He claims, in effect, that he had given the engineer a signal to stop, and had reason to believe that the signal was seen and obeyed; that before he went between the rails the train had stopped, or, if not, that it had so nearly stopped that he believed it was not in motion; that while he was between the rails the engineer, without a signal, or in obedience to a signal negligently given, put the train in motion. It was therefore important to show that the engineer had been given a signal to stop; and the alleged declaration of Collins related to an important, if not a vital, issue in the ease. If the only signal to the engineer before the accident was given by the conductor, and was designed to lessen the speed of a moving train, and was obeyed, then, presumptively, it was the plaintiff, if anyone, and not the defendant, who was negligent. The declaration in question tended to show that the engineer received a signal to stop. If he received such a signal, and the plaintiff was justified in believing that it was obeyed, the jury might well have found that it was negligence for the, engineer to start the train or increase its motion without a signal, or for the conductor to give a signal which would have that effect. There was much conflict in the evidence as to these matters, the greater number of witnesses testifying against the claims of the plaintiff. Moreover, the testimony he gave was not in all respects clear and satisfactory. Under these circtimstances it would be natural for the jury to give weight to the statements of Collins in question, as those of an eye witness and participant in the transactions to which they related, made at times when he was free from possible constraint, and therefore probably true. Another effect of the statements *318“waul'd be to show that the witness was unworthy of belief, and' to that extent they would be impeaching ■evidence We think they must be regarded as independent evidence for an improper purpose. As the record fails to satisfy us that no prejudice resulted from “their admission, but, on the contrary, leads us to believe that prejudice of so serious a nature resulted that the charge of the court did not cure it, the error must result in a reversal of the judgment of the district ■court.
III. During the trial the plaintiff, as a witness, stated on direct examination that the engineer obeyed 3. -: -: -. his signal, and that he thought that the cars stopped. On cross-examination he was asked if he did not swear in the petition, and if it was not true, that the engineer did not stop. An objection to the question, as not proper on cross-examination, was sustained. We think the ruling was erroneous. In view of what the witness had testified to on direct examination, it was entirely proper to show on cross-examination that he had ‘ made contradictory statements in his petition or otherwise. The fact that he had stated in his original petition that the negligence of the defendant consisted in the failure of the engineer to stop would not prevent his amending his petition, and showing that ^the negligence of the defendant related to the starting of the train. He may not have known which theory of the case was correct, and was entitled- to rely upon the one which “the evidence supported; but it was the right of the defendant to show that the plaintiff had made contradictory statements in regard t,o the matter, in order that the jury might give no more than due weight to Ms testimony.
Numerous questions are discussed by counsel which may not arise on another trial, and for that reason they are not determined. For the errors pointed out the judgment of the district court is reversed.