The ninth rule forbids the circulation of innocent books by heretical writers unless the names of the authors are expunged. The sixteenth restrains the circulation of manuscripts. The nineteenth limits the printing of sacred and ecclesiastical books to cities where the aid of an inquisitor may be had; and the books printed must be conformed to the exemplar in the Vatican. The twentieth directs visitations of booksellers’ shops, and forbids private persons to burn proscribed books, ordering them to deliver such to the master of the sacred palace or to the local inquisitor. The twenty-first prescribes the expurgation of sacred or ecclesiastical books, such as the _Decretals_, etc., which have been corrupted by heretics. The twenty-second warns the faithful that if they offend by reading or retaining the prohibited books, they will incur a sentence of excommunication, from which they can be absolved only by papal authority, except in the hour of death, and then only upon giving evidence of true penitence. The rules conclude with an instruction to booksellers to possess themselves of the present authoritative Index in order that they may have no pretext for ignorance. A similar instruction is given to all who concern themselves with the reading or possession of books that they are to possess and read this same Index. Sixtus died a few weeks after the printing of his Index, and when but few copies of the same had been sent out. Reusch states that (as was the case with the Sistine edition of the Vulgate) no further copies were distributed after the Pope’s death, and the copies which had been sent out were, as far as possible, recalled and the edition was destroyed. The copies of the original issue are, therefore, at this time very scarce. In 1835, however, the Sistine Index was reprinted by Mendham under the following title: _Index librorum prohibitorum a Sixto V Papa, confectus et publicatus; at vero a successoribus ejus in sede Romana suppressus. Edenta Joseph Mendham, London, 1835._ The Index is classified in three divisions. The heading of the second division does not, I believe, appear in any other published Index: _Deinde adduntur nomina Catholicorum quorum libri aut auctoris incuria, aut etiam impressoris negligentia, doctrinam non sanam, sed suspectam, et bonorum morum offensivam continere videntur_. It is to be noted that the possibility is admitted of the appearance in the works of Catholic writers of doctrine that is unsound or that is offensive to good morals. The right purpose or intention of such writers may be protected under the term “appear” (_videntur_).