Article 31

Let no one dare to publish again books proscribed by the Apostolic See; but if, from a grave and reasonable cause, some singular exception in this matter should seem to be admitted, that shall never be done unless the license of the sacred Congregation of the Index has first been obtained, and the conditions prescribed by it have been observed.

Force of the sanction

106. This is the force of that article: that it prohibit a book, prohibited by a special Decree, from being published even when corrected. But it says that the Sacred Congregation of the Index must be approached, and that its laws must be observed.

What if a book prohibited anew is published?

Indeed, as long as the proscribed book comes forth as morally the same, the new edition itself is affected by the decree of proscription, unless it has been positively permitted by the Sacred Index. Nor does it matter that the book was condemned only until it should be corrected. Cf. the preface of the Index, and the things said above, n. 46, 47.