“ Section 466 requires such a certificate for an appeal from a judgment denying a petition for habeas corpus when the petition complains of 'detention * * * by virtue of process issued out of a State court.' Since the statute authorizes either the district court or 'a judge of the circuit court of appeals' to issue the certificate, the district judge, in his order, stated that petitioner might apply to a judge of the court of appeals for the certificate and for the allowance of his appeal. ”

“ It is true that where a state court has considered and adjudicated the merits of a petitioner's contentions, and this Court has either reviewed or declined to review the state court's decision, a federal court will not ordinarily reexamine upon writ of habeas corpus the questions thus adjudicated. See Ex parte Hawk, supra, 321 U.S. at page 118, 64 S.Ct. at page 450. But that rule is inapplicable where, as here, the basis of the state court decision is that the particular remedy sought is not one allowed by state law, for in such a case this Court lacks jurisdiction to review the decision. ”

“ But § 262 of the Judicial Code, 28 U.S.C. § 377, 28 U.S.C.A. § 377, authorizes this Court 'to issue all writs not specifically provided for by statute, which may be necessary for the exercise of (its jurisdiction) , and agreeable to the usages and principles of law.' By virtue of that section we may grant a writ of certiorari to review the action of the court of appeals in declining to allow an appeal to it. ”