William Strong, Tilden v. Blair — Opinion of the Court
“ It is plain, therefore, that the contract is an Illinois contract, and that the rights and liabilities of the parties must be determined according to the law of that State. By its statutes persons may contract to receive ten per cent. interest upon any debt due them, whether it be verbal or written. If they stipulate for a higher rate they forfeit the interest, but the statute expressly allows the recovery of the principal. The contract is not declared to be void. Only so much of it is void as exacts the excessive interest. ”
