See this online ebook:
- The Catholic Church the True Church of the Bible, by Very Rev. C. J. O’Connell (St. Louis, MO, Freiburg (Baden), London: B. Herder, 1913). With Imprimatur. Available in various formats (pdf, epub, mobi/kindle, etc.) at Internet Archive and Open Library; and also available at HathiTrust Digital Library.
“[O]ur separated brethren… are not blessed with that unity which Jesus Christ wished to bestow.. For it is only through Christ’s Catholic Church, which is “the all-embracing means of salvation,” that they can benefit fully from the means of salvation…
“[W]hen the obstacles to perfect ecclesiastical communion have been gradually overcome, all Christians will at last, in a common celebration of the Eucharist, be gathered into the one and only Church in that unity which Christ bestowed on His Church from the beginning. We believe that this unity subsists in the Catholic Church as something she can never lose, and we hope that it will continue to increase until the end of time.” (Second Vatican Council, Decree on Ecumenism “Unitatis redintegratio”, 3, 4)