“It may be said in general that the Index legislation, as formulated by Leo XIII, is no longer as severe as formerly; it has been modified in the sense of mitigation. For example, a book written by an American for the purpose of education or instruction for instance in the Scriptures, is no longer _ipso facto_ forbidden. As far as the Index is concerned, such books may be freely read by Catholics who may need them.... The famous ‘Ten Rules’ of the Index issued under the authority of Pius IV (1564) are to be interpreted to-day by the Constitution ‘_Apostolicae Sedis_’ issued by Pius IX, a Constitution which reformed considerably the well-known system of censures, excommunication, and the like, and which is to-day the juridical source of general ecclesiastical censures of all kinds. In the _Compendium Juris Ecclesiastici ad usum cleri_, written by the Austrian Bishop, Simon Archner, Bishop of Brixen, (the sixth edition of which was printed in 1887), you will find (on page 521) the following passage: “‘The ecclesiastical prohibition of books, whether placed _nominatim_ on the Index or forbidden by its general rules, whether forbidden by the natural law or by the positive law, remains still intact. Therefore, such prohibited books cannot be printed, read, or kept _sine peccato_. But, at the same time, certain modifications of these prohibitions remain also in force, modifications which have doubtless been introduced in various regions through legitimate custom. As to Germany, authors of authority mentioned by the Council of Vienna have maintained that profane books written by heretics, on special subjects, as law, medicine, philosophy, history, etc., although they may contain one or more heresies scattered throughout the text, heresies held by the authors _obiter tantum_, do not fall under the ecclesiastical prohibition. They say the same of those writings of Catholic authors, otherwise worthy books, which contain one or more doctrines that are not entirely in accord with Catholic theology, the sacred canons, and the constitutions of the popes, and which in certain matters may exceed the proper limits in comment on subjects that the writers ought not to touch. This moderation is extended also to the rules of the Index which are scarcely anywhere received in their entirety, and which still less can be republished in this century _ex integro_. Finally, in Germany, even those writings of non-Catholics may, generally speaking, be safely read by Catholics which speak of religious matters in a manner conformable to the doctrine of the Church; and especially is this the case with the works of writers who may seem to be nearing conversion to the Catholic religion. On the other hand, no such license can be given to writings which treat of obscene matter, superstitions, magic, incantations, and the like; such