Pursuant to the provisions of the St. of 1869, c. 161, which makes the Cambridge and Brookline Bridge a public highway, and apportions the expense of rebuilding and maintaining the same, the commissioners appointed by this court have made a report, to which the county of Middlesex objects. The city of Cambridge in the county of Middlesex, and the town of Brookline in the county of Norfolk, are required to rebuild the bridge and keep it in repair; the north half being assigned to Cambridge, and the south half to Brookline; the division line between them, which is also the division line of the counties, passing through the centre of the draw. The sum of $5750 is ordered to be reimbursed to the inhabitants of Brookline, and of this sum two thirds is to be paid by the county of Middlesex and one third by the county of Norfolk. Of course the money is to reimburse them for rebuilding that part of the bridge which is situated in the county of Norfolk. It is objected that this requirement is illegal. It is not denied that the terms of the statute are broad enough to sanction the decision of the commissioners; but it is objected that the legislature has no power to provide that one county shall be compelled to contribute towards erecting or maintaining a bridge in another county. But a similar objection, in behalf of a town which was required to contribute towards the expense of erecting a bridge within the limits of another town, has been held to be invalid. Commonwealth v. Newburyport, 103 Mass. 129. And the same principle must apply to a county.
The general rule, that bridges and highways shall be maintained by the counties and towns within which they are situated, originated in the legislature; and the power that established it may repeal or modify it. As a general rule, it may be substantially convenient and equitable; and either convenience oi *239justice may require that it shall not be inflexible. The discretionary power of the legislature in the distribution of public burdens of this character has been for a long time recognized by this court. Norwich v. County Commissioners, 13 Pick. 60. Attorney General v. Cambridge, 16 Gray, 247. Hingham Quincy Bridge & Turnpike Co. v. Norfolk, 6 Allen, 353, 359, Salem Turnpike & Chelsea Bridge Co. v. Essex, 100 Mass. 282.
It is further objected that a specific sum is ordered to be paid by the county of Middlesex to the town of Brookline, while it does not appear what sum it will cost the town to rebuild its portion of the bridge, nor is any security required that the money shall be expended in the work. The sum is to become due on the acceptance of the report, and the bridge is not to be rebuilt till a later period. But the legal liability of the town to build the bridge is itself a security that it will be properly done. The exact expense of the work cannot be known until it is built, or at least contracted for; and an estimate of the commissioners was practically a convenient method of determining the matter. We think there can be no reasonable objection to their report. Report accepted.