As to the further extension of infallibility, or the specific definition of all the matters included in the term “de fide et moribus,” the fathers of the council postponed their decisions to a later day, and probably will consider them when the council is re-assembled. In the meantime, we have to be guided by the teaching of the best theologians whose doctrine is consonant to the practice of the Holy See. We may refer the curious reader to Father Knox’s little work, _When does the Church Speak Infallibly?_ as the safest source of information concerning this important point. As a matter of fact, the popes do teach with authority many truths which are not articles of faith, and condemn many opinions which are not heresies. Moreover, they command the faithful to assent to their teaching, and frequently punish those who refuse to do so. It is much more logical, and much more consonant to sound theological principles, to believe that they are infallible in respect to every matter in which they justly command our absolute and irrevocable assent, than to believe that we are bound to render this obedience to a fallible authority. But of the obligation in conscience to submit to all the doctrinal decisions of the Holy See there is no question. And this obligation is very distinctly and emphatically declared by Pius IX., with the concurrence of the universal episcopate, in the closing monition of the First Decree of the Council of the Vatican. “Since it is not enough to avoid heretical pravity, unless those errors also are diligently shunned which more or less approach it, we admonish all of the duty of observing also those constitutions and decrees in which perverse opinions of this sort, not here expressly enumerated, are proscribed and prohibited by this Holy See.” THE ARCHBISHOP OF WESTMINSTER’S REPLY TO MR. GLADSTONE. BISHOP ULLATHORNE ON THE SAME SUBJECT. BISHOP VAUGHAN ON THE SAME. LORD ROBERT MONTAGU ON THE SAME, ETC.--All published by The Catholic Publication Society. New York: 1875.