. Granger, J.
*6641 *6652 *6663 *663I. The condition of the record leads us to understand that the amendment to the petition, to which the demurrer was directed, was treated as a separate count; for, after it was held bad on demurrer, the case proceeded to trial as to the original petition. It will be seen that the amendment was filed some four years after the accident occurred, and actions of this character are barred by the statute of limitations in two years. The demurrer to the amend*664ment raises the question whether it presents a new or separate cause of action, so as to come within the operation of the statute of limitations. A reference to 'the averments of the original petition will show that the negligence charged is in using different systems of drawbars or bumpers in the coupling of its trains on the day of the accident, instead of the ordinary, improved drawbar or bumper, on its line of road. The acts of negligence charged in the amendment are entirely different, and show a right of recovery independent of, and without regard to, the acts charged as negligence in the original petition; the latter negligence being in the way and manner of using the drawbars, — in having them loose and out of repair, — so that the injury arose from negligence in the way the drawbars were used, and not from the fact that different systems were used. Appellant thinks that this question comes clearly within the rule of Kuhns v. Railway Co., 76 Iowa, 67, and appellee thinks that it comes as clearly within the rule of Van de Haar v. Van Domseler, 56 Iowa, 671. We think the latter case controls. In the Kuhns Case, recovery was sought because of negligence in not properly ballasting the road, spiking the rails, permitting the track to be uneven, operating an unsuitable -engine, and running it backward, because of which the engine was derailed and upset, causing the injury. Later, and after the period of the statute of limitations had run, the petition was amended by stating that when the engine was derailed it was running at a high rate of speed over the imperfectly constructed and uneven road, and that one of the wheels dropped into' a low place on the roadbed, and was broken, thereby causing the derailment and injury. This was held not to be stating a new or separate cauise of action, and clearly it was not. It is not clear that every additional fact might not have been proven without the amendment. The original averments are, in substance, that the faulty condition of the track made it dangerous to operate the engine over it, while those in the amendment showed that in the *665operation of the engine over the track the derailment was caused. The averment as to the speed of the engine is only that it was dangerously high over the uneven road. In that case the substance of the pleading is but slightly, if at all, changed. Now, let us look to the Van de Haar Case. It was a suit for damages for seduction. The amendment filed, after the statute had run, made a cause of action for forcible defilement or rape. It was held to be a separate cause of action, and properly so-. It is true that in the first-cited case the recovery was sought because of negligence, and in the latter case the recoverv was sought because of unlawful intercourse; but a “cause of action,” as the term is used in pleading, is not the name under which a state of facts may be classed, but it consists of the facts giving rise to the action. An action is a proceeding in court. Code, section 3424. The cause of action is the fact or the facts that “justify it or show the right to maintain it.” Hence, when a material fact, necessary to a recovery, is omitted from a petition, we say it does not state a cause of action. In 5 Am. & Eng. Enc. Law, 776, it is said: “The cause of action is the entire state of facts that gives rise to an enforceable claim. The phrase comprises- every fact which, if traversed, the plaintiff must prove in order to obtain judgment.” This definition is taken, substantially, from the case of Read v. Brown, 22 Q. B. Div. 128. In that case it is said that a cause of action is “every fact which it would be necessary for plaintiff to prove, if traversed, in order to support his right to the judgment of the court.” It is then said: “It does not comprise every piece of evidence which is necessary to prove each fact, but every fact which is necessary to be proved.” In Hutchinson v. Ainsworth, 73 Cal. 452 (15 Pac. Rep. 82), speaking of a cause of action with reference to the statute of limitations, it is said: “The facts upon which the plaintiff’s right to sue is based, and upon which the defendant’s duty has arisen, coupled with the- facts which constitute the latter’s wrong, make up the cause of action.” *666See Bruilt v. Association, 72 Wis. 430 (39 N. W. Rep. 529), and Rapalje & Lawrence Law Dictionary, 180. Care should be taken not to confuse the term “cause of action” as used abstractly and as used in pleading. In a general sense, the term means “a claim which may be enforced.” Bucklin v. Ford, 5 Barb. 393. “It is a right which a party has to institute and carry through an action.” Myer v. Van Collem, 28 Barb. 230. “The right to prosecute an action with effect.” Douglas v. Forrest, 4 Bing. 704. Looking to these cases, it will be seen that the term “cause of action” is used with no purpose to indicate a rule by which one cause of action may be distinguished from another, but merely with reference to the existence of a cause of action. We use expressions like these: “A cause of action for negligence;” “a cause of action for malicious prosecution;” “a cause of action for desertion.” They indicate the subject or subject-matter of the action, but are meaningless as showing a particular cause of action. In Rodgers v. Association, 17 S. C. 406, are the following query and answer: “What is a cause of action ? We must keep' in view the difference between the subject of the action and the cause of the action. The subject of the action was what was formerly understood as the subject-matter of the action. * * * The cause of action is the right claimed or wrong suffered by the plaintiff, on the one hand, and the duty or delict of the defendant, on the other; and these appear by the facts of each separate case.” We have emphasized closing words to call especial attention to the rule when applied to a particular case. The application of the rule to this case leaves no doubt what the conclusion should be. The original petition stated a complete cause of action, and the amendment stated another. The two causes of action are SO' distinct and separate that either could be established without reference to the fact of negligence alleged in the other. Appellant says the cause of action is “the injury wrongfully inflicted by the defendant through the negligence of the defendant.” That means a cause of action *667based on defendant’s negligence, and, if that is the meaning of the term, for the purposes of pleading, then no amendment would be vulnerable to the objection that it stated a separate cause of action, so loaig as the facts pleaded constituted negligence. No authority that we have seen sustains such a rule. A case in point and quite instructive, is Railway Co. v. Wyler, 158 U. S. 285 (15 Sup. Ct. Rep. 877). The action was instituted in Missouri by Wyler for injuries caused by a fellow servant in the state of Kansas, and, as the law of Missouri did not make the master liable for the negligence of a fellow servant, the charge of negligence against the company was in its employing and retaining an incompetent person who caused the injury. This plea was filed within the statutory period. After the statute had run, Wyler amended his petition by averring that Kline, the fellow servant, was negligent, and caused the injury, so as to bring the case within the law of Kansas, which is like ours, so that, while the action was still for negligence, there was a change of averment as to the particular facts constituting the negligence. The court held that the amendment stated a new cause of action, so that another rule of law obtained, and that it was barred by the statute. The court speaks of it as a “departure from law to law,” and then, as to the facts, it says: “If the charge of incompetency in the first petition was not per se a charge of negligence on the part of the fellow servant, then the averment of negligence, apart from incompetence, was a departure from fact to fact, and therefore a new cause of action.” The case announces a very conclusive rule. See, also, Railway Co. v. Scott, 75 Tex. 84 (12 S. W. Rep. 995). In that case Scott was injured on defendant’s road, and brought suit, which' was settled by the payment of money, and an agreement to employ Scott. Scott brought suit for a breach of the agreement to employ him, averring that the employment was to be, as to time, at his option. After the period of the statute of limitations had run, he amended simply as to the one fact of time he was to be employed, charging that it was to be during his life. The case holds that it was *668a statement of a new cause of action. The thought obtains throughout the case that even though the amendment might otherwise be allowable, it will not be permitted when the effect will be to make the state of facts pleaded relate back so as to avoid the statute of limitations, if the new cause of action would be otherwise barred.
4 II. The cause proceeded to trial on the issues joined as to the original petition, and at the conclusion of the evidence the court directed a verdict for defendant. On this branch of the case the only question of negligence is that involved in the use of the kind of drawbars or bumpers, and not in the way they were used. A ground of the motion to direct a verdict is that the plaintiff, because of his knowledge of the use of the drawbars in question, and continuing in defendant’s service with such knowledge, waived all rights of complaint because of their use. The rule of this state, as applied to facts upon which the motion is grounded, has been long recognized, and is concisely expressed by Mr. Justice Day in Perigo v. Railway Co., 52 Iowa, 276, in the following language: “It is now the established doctrine of this court, in harmony with the current of authority elsewhere, that an employe who knows, or by the exercise of ordinary diligence could know, of any defects or imperfections in the things about which he is employed, and continues in the service without objection, and without promise of change, is presumed to have assumed all the consequences resulting from such defects, and to have waived all right to recover for injuries caused thereby.” The same rule, in substance, has often been approved in different cases, and among them are Muldowny v. Railway Co., 39 Iowa, 615; McKee v. Railway Co., 83 Iowa, 616; Mayes v. Railway Co., 63 Iowa, 562; Scott v. Coal Co., 90 Iowa, 689; Cowles v. Railway Co., 102 Iowa, 507. The evidence, without substantial conflict, brings the case within the rule as stated. The facts conclusively appear from plaintiff’s own testimony. It is not important to set out the evidence or enlarge upon it. The judgment is aeeirmed. • .