Deemer, J.
On the forenoon of May 15, 1890, Earl Thomas, a minor son of plaintiff, aged three years and ten months, was, with a little companion, playing upon an open, uncovered bridge, located upon the defendant’s main line of road, about one thousand nine hundred feet west of the station of Rhodes', and, while there at play, was run over by a train going towards the west, and his right foot and log were so maimed and crushed as to necessitate amputation. It is averred in the petition that, without fault on the part of his parents, the child went upon the track and the bridge, and was in plain sight from the station, and at all points along the road leading from the station to the place of accident; that defendant’s employes, with knowledge that the children were upon the track, started a train from the water tank at the station, a distance of about ninety rods from the bridge, westward (the engine being in front, but with the tender foremost, and with the pilot *250attached to the cars), and negligently and carelessly ran the train over the plaintiff’s child; that there were four .persons (the engineer, fireman, conductor, and br&keman.) upon the engine, and each of them knew that the child was upon the track and bridge; that the employes of defendant negligently started the train, and, for some distance from the tank, did not look along the track over which they were going, or exercise any degree of cane or caution in the operation of the train, or to discover whether or not the track was clear; that the train was a wild train, not running on schedule time, and was running with engine backwards; that the train was not manned with a sufficient number of brakemen; and that the engine was Avithout steam or air brakes. Plaintiff further averred that the engineer and employes upon the train saw the child, with his playmate, upon the bridge, at a greater distance than was necessary, with proper effort, to stop the train, and knew the perilous position they were in, but that they negligently allowed the engine and train to approach and reach the bridge without signal of bell or whistle, and without any effort to stop the train, or remove the children from the track, and negligently and carelessly ran upon and injured plaintiff’s child. The defendant, in its answer admitted the injury done to the child, by Avhich it lost its leg, but denied each and every other allegation in the petition. On the issues thus joined, there was a trial to a jury, and a verdict returned for plaintiff, on which judgment was rendered, and defendant appeals.
The court below, in its instructions, eliminated from the case all charges of negligence, except the last one in the petition, viz., the one alleging that the defendant’s employes were negligent, after they saw the children upon the track, in failing to use all available means at hand to stop the train, and avoid injuring them. This charge of negligence was submitted to *251the jury, and, in answer to special interrogatories, the jury found that the engineer and employes in charge of the train did not do all they could, with the appliances at hand, to stop the train as soon as they discovered the children upon the track. The jury also> found, specially, that the train could have been stopped by the defendant’s employes, with the appliances at hand, after they saw the children on the bridge, in time to have prevented the accident. And they further found that the engineer did not whistle for brakes, and reverse his engine, as soon as he knew the objects on the track were young children. The court, in effect, instructed the jury that defendant’s employes were not bound to anticipate that young children would be upon the bridge in question, and in danger from passing trains, and that they were not required to' keep a constant lookout to discover children on the track, and that neither the fact that the engine was running backwards, nor that it was running at a high rate of speed, would, of itself, constitute negligence. But it also instructed that if the employes of defendant who were operating the train saw the plaintiff’s child upon the railroad. track or bridge, and knew that he was too young to take care of himself, then they would not be justified in assuming that the child would step aside and avoid injury, and that in such case it would be the duty of such employes to employ every available means at their command to stop the train, and avoid injuring the child, and, if they failed to do so, then the company would be responsible. The court also gave proper instructions with reference to the care required of 1 plaintiff to prevent his son’s going upon the track, and, further,- gave the following: “You are instructed that the bridge and track where the plaintiff’s son was injured was and is solely and exclusively for the use of defendant in operating its *252trains, and the plaintiff’s son had no right or license of any kind to be there; and the fact, if it be a fact, that people constantly walked upon it, would not give them any right to do s-O'. No matter how often people- may haye walked upon it, they would be doing so without right or authority; and any testimony that has been introduced tending to show that people occasionally walked upon it, if any Such has been introduced, can only be considered by you in determining the question whether or not the engineer and employes in charge of the train actually saw the plaintiff’s son in time to have stopped the train, before reaching the child, with the means and appliances then at their disposal.” There was testimony in the case that the right of way where the child was injured was much frequented by pedestrians, in passing from a highway, a few rods west of the bridge, to the town of Rhodes, and the instruction was intended to apply to this state of facts.
We think the instruction is wrong — First, because the latter part of it entirely neutralizes the first, part; and, second, because it announces an incorrect proposition of law. The first part of the instruction clearly announces the rule that the children were trespassers, and had no right or license to be upon the track or the bpidge. If they were trespassers then the company owed them no duty until its employes actually saw them upon the track, and in a place of danger. Then, and not till then, did any active duty on the part of the defendant’s employes commence. It has long-been the established rule in this state that a railroad company is not required to keep a lookout for trespassers, and that it is not negligent in failing to discover them upon its track. This is an undoubted rule, sustained by an unbroken line of authorities. See Masser v. Railway Co., 68 Iowa, 602, 27 N. W. Rep. 776; Burg v. Railway Co,, 90 Iowa, 106, 57 N. W. Rep. 680; *253Morris v. Railroad Co., 45 Iowa, 29; Richards v. Railway Co., 81 Iowa., 426, 47 N. W. Rep. 63. We are aware that a different rule bas been beld in some of our sister states. See Railroad Co. v. Grablin (Neb.), 56 N. W. Rep. 796, and authorities cited. But the question cannot, in view of the cases before cited, be considered an open one here. It may also be remarked in this connection that a license to. use the track of a railroad company may be inferred from frequent use, in connection with other circumstances from which an 2 implied invitation may be inferred. See Clampit v. Railroad Co., 84 Iowa, 71, 50 N. W. Rep.. 674. The instruction, however, assumes that there was no license to use the track and bridge of the defendant company; and yet it proceeds to say that the fact that persons occasionally walked upon the track may be considered, in determining whether the engineer saw the children or not, in time to have stopped the train. Clearly, this neutralizes and contradicts the first part of the instruction, and could have no other effect than to mislead and confound the jury. If defendant’s employes were not required to be on the lookout for them children, because they were trespassers, and are not bound, in any case, to be on the lookout for trespassers, it is somewhat difficult to understand how the- fact that persons occasionally trespassed upon the track at the place in question would throw any.light upon the question as to when defendant’s employes saw the plaintiff’s child. The vice of the instruction becomes the more apparent when read in the light of the testimony that the engineer of the engine in question had never seen persons using the track as a footpath. Moreover, if there had been no such testimony from the engineer, the jury could not well infer that the engineer had seen others trespassing upon the track, for he was un derm q,duty do look *254out for them; and, being charged with no such duty, the inference is just as strong that he did not see them as that he did. Again, the latter part of the instruction is wrong because it practically announces the rule that if persons occasionally trespass upon the track of a railway, whether known to the employes of the company or not, that it then becomes the duty of the engineer .of a train to look out for further trespassers upon the track; or, to put it in other words, that occasional trespasses, whether with the knowledge of the company or not, are material in determining the question as to whether a particular trespasser was seen by the engineer in charge of a train. Such a rule if established, would require an engineer to keep' a constant lookout for trespassers on the whole of the line oyer 3 which he is running. We do not think support can be found for such >a, rule in any case. It is insisted, however, that the instruction is without prejudice, because of the special findings' of the jury, before set out, wherein it was found that the engineer saw the child in time to have stopped the train, and avoided the injury. We do not think so. The jury, in the condemned instruction, were directed to consider these occasional trespasses in determining the question as to when the engineer saw the children, and their finding as to when the engineer saw the children may have been based upon this faulty instruction. When error is committed, prejudice will be presumed, and it must affirmatively appear’ that the error was without prejudice.
II. Counsel have discussed at some length the question as to whether a child of tender years can be a trespasser, or not, and appellee’s counsel have cited some authorities holding that it cannot be. Other authorities cited hold that a child1 of the age of the one injured in this case cannot be guilty of contributory *255negligence. The rule last referred to is unquestioned, and we may sa.y that there is no question of contributory negligence on the part of the child in this case. The infant was of such tender years that it was not sui juris, and we think, as a matter of law, it should be held it was not guilty of contributory negligence in going upon the track. But the other is quite a different proposition, and .some confusion is apparent in the authorities, because courts have not always drawn proper distinction between trespassers and those who are guilty of contributory negligence. The reason, as we understand it, why a trespasser cannot recover for injuries inflicted upon him by the negligence of another, is because the one who is negligent owes the trespasser no duty, .and is not required to be on the lookout for him. In order to maintain an action for negligence, it must appear that there was a legal duty due from the person inflicting the injury to the person on whom it was inflicted, and that such duty was violated by a want of care on the part of the wrongdoer commensurate to the duty imposed. Cooley, Torts, pp. 659, 660. There must be a breach of some duty owing to plaintiff, or to those whom he represents, to constitute actionable negligence. Now, as we have already seen, the only duty the engineer of a train owes to a trespasser 4 is to avoid injuring him after his peril is discovered. And, in determining this question, of duty, it is entirely immaterial whether the trespasser is sui juris or not, for the inquiry is not as to the ability and capacity of the trespasser, but rather the duty of the one who is charged with the negligent acts. For this reason the better considered cases hold that it is entirely immaterial that the trespasser is an infant, idiot, or lunatic, in determining whether he was a trespasser. See Burg v. Railway Co., supra; Masser v. Railway Co., supra; Nolan v. Railroad Co., (Conn.). 4 *256Atl. Rep. 110; Morrissey v. Railroad Co., 126 Mass. 380; Chrystal v. Railroad Co., 105 N. Y. 170, 11 N. E. Rep. 380. When the duty once commences, no doubt a higher degree of care is required1 to avoid injuring a child, than is required where the trespasser is an adult. But active duty commences no sooner in one case than in the other. The reason why one who by his negligence directly contributes to his injury cannot recover, is entirely different. In such case, he, by his own volition, is in the wrong, and cannot be heard to take advantage of Ms own culpable neglect. Therefore, an infant, who is not sui juris, cannot be guilty of contributory negligence. With these distinctions in mind, most of the cases cited can be reconciled, and from them the rule deduced that a railroad company owes no duty to a trespasser, be he sui juris or not, until its employes actually discover him upon the track, and that the question as to the age of the child is not important in determining when the duty commences. But, where the question presented relates to the contributory negligence of the person injured, then Ms age is of great moment, for if he is not sui juris he cannot be held 5 guilty of contributory negligence. In order that we may not be misunderstood, it is perhaps well to say that there is an apparent exception to the general rule abo v@> stated, in what are known as the “Turntable Oases.” But we think the exception is not in fact an exception, but rather an extension of the principle to cover a different state of facts. In the tumtablé and other like cases, the defendants are held liable because the nature of the machine or agency which caused the injury was such as was well calculated — was of such a nature, and left in such a position, as that it was likely — to attract children. The temptation thus presented to children is, in the cases just *257referred to, made to take the place of an express invitation to an adnlt, and with much reason. See Railroad Co. v. Stout, 17 Wall. 657, and other cases cited in Beach, Contrib. Neg., section 207 et seq. Without committing ourselves to the doctrine of this exception, it is sufficient to say that it ha>s no application in the case at bar.
III. In thei sixth instruction the jury were told that defendant’s employes were not required to be 6 upon the constant lookout to discover children at that place, — the place of the accident. In view of a retrial of the case, it is perhaps well to- say that we think this instruction ought not to have been given. While it doe® not directly ®ay that the engineer wa® required to keep a lookout for trespassers, yet such meaning could well be placed upon the language used. The inference is quite strong that, while he was hot required to keep' a constant lookout, yet some effort in this direction was required. The case was presented to the jury on the theory that the child wa.s a trespasser, pure and simple; and, as we have seen, the defendant did not owe it the duty to look out for it. We would not reverse the case on this ground alone, and say what we do in order that the instruction may not be repeated upon a retrial.
IV. In the eighth instruction the jury were directed to consider whether any of the employes on the defendant’s train were negligent after they discovered the plaintiff’s child upon the track, and measure the duty required of an employe under such circumstances as given. And in the special interrogatories the jury were directed to' answer as to Whether any of the employes in charge of the train were negligent or not. It is insisted that this was error, because there was no evidence that any of the employes, other than the engineer, were negligent. To this it may be said that, con*258ceding the error, — and this we do simply for the purpose 7 of the case, — it was one into which the court was led by defendant’s counsel. In the interrogatories submitted by them, they asked for answers to substantially the same questions, and in the instructions they presented, the same thought was presented. We do 'not think they are now in a position to urge the objection.
Y. Appellant earnestly contends that there is. no evidence of negligence on the part of the engineer sufficient to take the ease to the jury. In view of a retrial, we do not think it advisable to discuss the question at this time, and therefore dismiss it without further consideration.
VI. Other questions are discussed, but, as they will not arise upon another trial, we do not consider them. It miay be said, however, for the guidance of the court, that the rule relating to impeaching testimony was not observed as closely as it should have been. For the errors above pointed out, 'the judgment of the District Court is reversed.