“A few words are needed to explain the principle of the new edition and its chief points of difference from the earlier ones. The intention of the Pope in ordering a thorough revision of the Index was not only to temper the severity of the old rules but also, on behalf of the maternal kindness of the Church, to accommodate the whole spirit of the Index to the times. In the actual compilation of the list of prohibited books some material modification has been shown and the number of books formerly prohibited has been diminished. This can be seen in the first Decretal, by which all books prohibited before the year 1600 are declared to be henceforth expunged from the Index, although they are to be considered as much condemned to-day as they ever were, with the exception of those permitted by the new Decretal. Hence in the case of condemned authors hitherto described in Class I, all of whose works were prohibited, by the present Index those of their works are permitted which either _ex professo_ do not treat of religion, or, if they do treat of it, contain nothing contrary to the Faith, unless they happen to have been prohibited by some general or special decree. And this mitigation may properly be extended to the case of non-Catholic authors whose complete works are expressly prohibited in the Index. This prohibition will not apply in future to those books which touch the Faith either not at all or only incidentally by the way, if these have not been noted by any general or special decree. Therefore the old distinction between ‘all works’ simply and ‘all works treating of religion’ might be cancelled as superfluous. For whenever the complete works of an author are prohibited, those works only are understood which either treat of religion or are proscribed by some general or special decree. “Moreover, certain books, not a few in number, have been dropped from the Index, which, although they labour under certain defects or have some slight taint, yet have such a reputation for learning or such documentary value that their errors or views seem to be compensated by their usefulness. “It was also thought best to delete a good many works which deal with the Immaculate Conception, soundly, it is true, but too intemperately or with some offence to adversaries. Again, a number in which domestic controversies and private quarrels were agitated with improper acrimony, to the injury of good feeling and with hardly any gain to truth; and some which deserved prohibition not by defective doctrine nor failure in charity, but by the indiscretion of the author in failing to obey the public injunction to silence for the sake of extinguishing private quarrels. These controversies having become extinct and the injunction to silence having been long ago removed, these books could be dismissed.