Purgatory, as a doctrine, is peculiar to the Catholic Church; Purgatory, as a discipline from sin to virtue, is a practice followed by a large portion of humanity. The latter fact explains why so many who reject the dogma, still love and admire Dante's Purgatorio, which, while it teaches the doctrine of the intermediate state, also serves as an allegory, the most helpful and beautiful allegory, perhaps, in the literature of the world. In the opinion of Dean Stanley, it is the most religious book he ever read. It makes a peculiar appeal to the modern mind because, as Grandgent says: "It's theme is betterment, release from sin and preparation for Heaven" ... (and) "its atmosphere is rightly one of hope and progress." Dinsmore declares: "Purgatory as a place may not exist in our system of thought, but life is a cleansing process if we take its hardships in a proper spirit." In another place he asserts: "In pondering the way of life by which this high priest of the Middle Ages (Dante) proclaims that men attain perfect liberty, we cannot but remark the stress he lays upon a principle which has well-nigh faded from the Protestant mind. It is that of expiation--(and) expiation is no musty dogma of the schoolmen, but a living truth.... Dante placed more emphasis on the human side of the problem than we, and for this reason he deserves attentive study, having portrayed most powerfully some truths which our age, so eager to break from the narrowness of the past, has overlooked." In agreement with this statement of the learned Congregational divine is William T. Harris, former United States Commissioner of Education, who observes in his "Spiritual Sense of the Divina Commedia," that if Purgatory is absent from the Protestant creed, the thought of which Purgatory in this life is the symbol, is not uncommon in non-Catholic literature. His exact words are: "If Protestantism has omitted Purgatory from its religion, certainly Protestant literature has taken it up and absorbed it entire," and for proof he points to the moral, among other books, of The Scarlet Letter, The Marble Faun, Adam Bede and Romola, all showing "That men may rise on stepping stones Of their dead selves to higher things."