The opinion of the court was delivered,
by Agnbw, J.
But two questions need to be noticed in this case — • the duty of repair and the liability of the townships for latent defects. Without a duty of repair no liability rests on the municipality. As a general proposition, but by no means universal, bridges are treated as portions of the -highways which cross them, and are to be maintained by the same persons to whom the duty of repairing the highways is committed: Shear. & Red. on Negligence, § 248. In this state the duty is statutory, and therefore we must look to the statute for its nature and extent. The 6th *407section of the Act of 13th June 1836 requires public roads or highways to be effectually opened and constantly kept in repair, and at all seasons to be kept clear of all impediments to easy and convenient passing and travelling, at the expense, of the respective townships, as the law shall direct. By the 10th section those laid out on a line which divides two townships shall be opened and kept clear and in repair at the joint and equal charge of such townships. The 27th and following sections require these duties to be performed through supervisors, to whom large powers are given for the purpose: Brightly 876, pl. 41, 42, 43, &c. Coming to the 34th section, it is provided that where a small creek over which a bridge may be necessary shall be the boundary, or on the division line of townships, the bridge shall be built and maintained at the joint and equal expense of said townships, by their respective supervisors, in the manner directed by law in the case of public roads, which may be the division line of the townships: Brightly 822, pl. 56. Thus it is clear that by law the primary duty of maintaining and repairing the bridge in question lay on the townships defendants jointly; the stream over which it -was built being on the division line between them. For this purpose the supervisors of roads of the respective townships were the agents constituted by law; and it is equally clear that the personal liability of the supervisors, for their neglect to perform this duty, does not lessen the primary liability of the townships to those who suffer injury from their neglect. These principles will be found to be fully supported by the following cases: Dean v. New Milford Tp., 5 W. & S. 545; Erie City v. Schwingle, 10 Harris 385; Pittsburg v. Grier, Id. 54 ; Humphreys v. Armstrong Co., 6 P. F. Smith 204; Penna. and Ohio Canal Co. v. Graham, 13 Id. 290; Meadville v. Erie Canal Co., 6 Harris 66. That an action on the case will lie at the suit of a party who has suffered a special injury, as in this case, is also shown by the same authorities.
But it is contended that the defect in this bridge being latent, no liability can be imputed to the townships until it is shown that notice of the defect was given to the supervisors in whose charge the bridge lay. This is the chief question, and is not without difficulty. The defect here was the inward rottenness of the timbers which constitute the main strength and chief support of the bridge. It was not outwardly visible, one of the supervisors having inspected the timbers outwardly a short time before it fell. But the evidence shows that the bridge had been erected and stood the time it is usual that such timber will last, that it was uncovered and open to the weather, and that the actual state of the timbers can be ascertained by persons having ordinary skill upon such a subject. It was testified that the internal condition of the timbers can be readily determined by boring into them at *408proper points. The question of liability for this latent defect was determined by the jury on these facts ; the court having instructed them that constant watchfulness, on part of the supervisors, was a duty to the public, and having left it to them to determine whether the supervisors had used ordinary care in performing this duty, and in-applying the proper tests to ascertain the soundness of the timbers of the bridge. That a municipal corporation, though bound to the duty of maintenance and repair, is not absolutely bound for the soundness of the structures it erects as parts of a public highway, must be admitted to be the general doctrine of the authorities on this question. It is not an insurer against all defects latent as well as patent, but is liable only for negligence in the performance of its duties. Hence it is said in Shear. & Red. on Negligence, § 148, as the result of the authorities, that when the defect in a lawful structure is latent or is the work of a wrongdoer, either express notice of it must be brought home to the corporation, or the defect must be so notorious as to be evident to all who have occasion to pass the place or to observe the premises, in which case the corporation is charged witheu-fr constructive notice, being in fault for not knowing the fact: Id. § 407. But what is negligence is itself a question in each case, and must always depend on its peculiar circumstances. “ Great danger demands higher vigilance and more efficient means to secure safety —where the peril is small, less will sufficeF. & B. Turnpike Co. v. Phila. & Trent. Railroad Co., 4 P. F. Smith 350. “ The degree of care having no legal standard, but being measured by the facts that arise, it is reasonable such care must be required, as it is shown, is ordinarily sufficient under similar circumstances, to avoid the danger and secure the safety neededId. Applying these principles here, it may be asked what structure more important in view of the safety of life and property, can be well imagined than such a bridge as this, having a span of 52 feet, crossing from 10 to 12 feet above the stream whose water is middle deep. The accident itself is evidence of its important character. The plaintiff’s wagon was overturned in the fall, the body crushed, the load of wheat fell underneath it into the stream, and one of the horses was killed. As remarked by our brother Read, “ A bridge looks fair till it breaks down; it is not like a pit which you can see and avoid.” “In practice it is used up to the last moment:” Humphreys v. Armstrong Co., 6 P. F. Smith 204. Hence such a structure demands constant vigilance to guard and preserve it. Therefore, when a bridge is old, having stood for the length of time the timbers composing it are accustomed to last, and when it may be reasonably expected that decay has set in, it is negligence to omit all proper precautions to ascertain its true condition. Nor will mere appearance in such a case excuse the neglect. It is a matter of common knowledge that invisible defects may, and *409under such circumstances probably do exist; that either wet or dry rot may have set in, and not be visible, and therefore should be sought for. But no one of ordinary intelligence would think of seeking for an inward and invisible defect by merely inspecting the surface of the wood. This being the case, it is clearly the duty of the supervisors, having thus reason to believe that defects may exist, to call to their assistance those whose skill will enable them to ascertain the true state of the structure, and determine the question of its safety. Without doing this much at least, their duty to the public is not performed. Not to do it is therefore negligence, and this is the point on which the case went to the jury. There is therefore no error in the submission. The exceptions to the evidence have but little merit, and are not properly assigned. They are therefore not noticed.
Judgment affirmed.