Hilgers calls attention to the method of procedure under which the successive Indexes collected into their lists the titles of books that had been condemned (in certain cases many years before) in specific decrees. The Index authorities have, he says, been criticised for bringing into condemnation books having to do with controversial questions, years after these questions have been practically adjusted or were no longer vital matters. The answer is that the literature was considered at the proper time under a separate decree and the Index merely presents a summary of such decrees. The Index of Leo XIII makes clear in its record of condemnations of earlier date the immediate source for each condemnation; whether this took the form of a papal brief or bull or whether it was arrived at through the decision of one of the papal Congregations. The books which have been condemned under a separate Apostolic edict (brief or bull) comprise in all a hundred and forty titles and these have been printed in each Leonine Index with a cross. During the three centuries between 1600 and 1900, the Congregation of the Holy Office, that is to say, the Roman Inquisition, has issued in all nine hundred book prohibitions. These are entered in the Leonine lists with the words: _Decr. S. Off._ During the same period, the Congregation of Rites has prohibited in all but three books. The Congregation of Dispensations has issued two condemnation decrees. It is clear from the above reference that each Congregation has been charged with the supervision of the literature belonging to its own special subject-matter. The Congregation of the Index, however, is concerned with the books in every division of literature because its subject is the examination and determination of works classed as suspected. The entries for which the Congregation of the Index is responsible during the three centuries in question aggregate about three thousand. As before stated, the power rests with the pope to examine and to pass judgment upon any book without the intervention of any one of the Congregations.