S74 7ESEBAL SEFOBTEB. �member of the community who may be able to bring himself ■within the provisions of such law : provided, always, the legisla- ture shall have power to grant such charters of incorporation as they may deem expedient for the public good.' " �Now, these decisions are direct and emphatic against the complainant's claim of exemption, and it is insisted that they are conclusive upon this court. If so, we are relieved from ail obligation "to exercise our own judgment." But is this court concluded by these decisions? Ordinarily, the federal courts adopt and follow the ruling of the state courts, in their interpretation of the constitution and statutes of their respect- ive states. This is the ruie. But to this rule there are exceptions, as well established as the rule itself. The federal courts "will foUow, as of obligation, the decisions of the state courts on local questions peculiar to themselves, or on questions respecting the construction of their own consti- tution and laws." But if a "contract, when made, was valid under the constitution and laws of the state, as they had been previously expounded by ita judicial tribunals, and as they were understood at the time, no subsequent action of the legislature or judiciary will be regarded by the federal courts as establishing its invalidity." Olcott v. Supervisors, 16 Wall. 678. �This principle was somewhat extended in the case of The Township of Fine Grave v. Talcott. 19 Wall. 666. In this case it appears that in March, 1869, the state of Michigan, by an act of its general assembly, authorized any township, city, or village in the state to pledge its aid. by loan or dona- tion, to any railroad company in the construction of its road. The defendant township voted aid to the road mentioned in the case, and issued its bonds therefor. At the time the^ con- stitutional power to do this was not controverted, but gen- erally conceded. Numerous acts recognizing this power had been passed by the legislature ; but, after the bonds in ques- tion had been issued and negotiated on the faith of this pop- ular and legislative construction of the constitution of the state, the supreme court of Michigan held, in two cases, that ail the acts authorizing such aid by counties, cities, and town- ����
