With the alteration of social conditions, however, the Rules of Trent ceased to be entirely applicable. Their application to publications which had no concern with morals or religion was no longer conceivable; and, finally, the penalties called for modification. Already, at the Vatican Council, several bishops had submitted requests for a reform of the Index, but the Council was not able to deal with the question. The reform was accomplished by Leo XIII., who, on the 25th of January 1897, published the constitution _Officiorum_, in 49 articles. In this constitution, although the writings of heretics in support of heresy are condemned as before (No. 1), those of their books which contain nothing against Catholic doctrine or which treat other subjects are permitted (Nos. 2-3). Editions of the text of the Scriptures are permitted for purposes of study; translations of the Bible into the vulgar tongue have to be approved, while those published by non-Catholics are permitted for the use of scholars (Nos. 5-8). Obscene books are forbidden; the classics, however, are authorized for educational purposes (Nos. 9-10). Articles 11-14 forbid books which outrage God and sacred things, books which propagate magic and superstition, and books which are pernicious to society. The ecclesiastical laws relating to sacred images, to indulgences, and to liturgical books and books of devotion are maintained (Nos. 15-20). Articles 21-22 condemn immoral and irreligious newspapers, and forbid writers to contribute to them. Articles 23-26 deal with permissions to read prohibited books; these are given by the bishop in particular cases, and in the ordinary course by the Congregation of the Index. In the second part of the constitution the pope deals with the censorship of books. After indicating the official publications for which the authorization of the divers Roman congregations is required, he goes on to say that the others are amenable to the ordinary of the editor and, in the case of regulars, to their superior (Nos. 30-37). The examination of the books is entrusted to censors, who have to study them without prejudice; if their report is favourable, the bishop gives the _imprimatur_ (Nos. 38-40). All books concerned with the religious sciences and with ethics are submitted to preliminary censorship, and in addition to this ecclesiastics have to obtain a personal authorization for all their books and for the acceptance of the editorship of a periodical (Nos. 41-42). The penalty of excommunication _ipso facto_ is only maintained for reading books written by heretics or apostates in defence of heresy, or books condemned by name under pain of excommunication by pontifical letters (not by decrees of the Index). By the same constitution Leo XIII. ordered the revision of the catalogue of the Index. The new Index, which omits works anterior to 1600 as well as a great number of others included in the old catalogue, appeared in 1900. The encyclical _Pascendi_ of Pius X.