“ This question was resolved by the Supreme Court of the state in favor of the husband; and at the instance of the opposing party the chief justice of that court allowed a writ of error bringing the judgment here for review. The writ obviously was improvidently allowed. Section 237 (a) of the Judicial Code (Comp. St. § 1214) restricts the cases in which we may review a judgment or decree of a state court on writ of error to those 'where is drawn in question the validity of a treaty or statute of the United States, and the decision is against its validity ”

“ The only federal question in the case is whether Congress intended by that section and other related congressional enactments that the surviving husband of the deceased should take an estate by the curtesy in the land. ”