After crossing the Styx (Canto viii.) we find a further change. Thus far the sins punished have differed only in degree from those which we shall find being expiated in Purgatory. They are indeed the simpler forms, so to speak, of the defects common to all animal nature. They are the same which, in one of their interpretations, the three symbolical beasts of Canto i. denote. Henceforth we find sins which are only possible to the higher intelligence of humanity. It will be observed, too, that at this point what may be called pictorial description begins. Hitherto we have had merely a general impression of murky air and miry soil, sloping perhaps a little toward the centre, and intersected now and again by a stream. Now the City of Dis with minarets and towers rises in front of us, and, as we shall see in future cantos, from this time onwards the character of the scenery is indicated with great preciseness, even to its smallest details. Here, too, actual devils, beings whose will, as Aquinas says, is obstinately set upon evil, appear for the first time, as distinct from the personages of classical mythology, who act as warders of the various circles. Virgil, or human reason, is no longer sufficient of himself to secure a passage. Both at the gates of the fiery city and on subsequent occasions he is as helpless, without superior aid, as his disciple and follower. The ninth canto contains a piece of allegory, that involved in the introduction of Medusa and the Furies, which has earned perhaps a greater reputation for obscurity than it deserves, from the fact that Dante himself calls special attention to it. Cantos x. and xi. are both very important, the former for its bearing on the history of Florence. Those who have read the sketch of that history in the preceding chapters will understand the full force of Farinata’s discourse with Dante. We have had a brief passage of the same kind in Canto vi., but here the subject is treated at greater length, and with some marvellous dramatic touches. Canto xi. must be thoroughly mastered if Dante’s scheme of ethics is to be understood. It forms, indeed, a summary of and key to the arrangement of the penalties, and a thorough comprehension and retention of it in the memory will be found a wonderful help to a recollection of the whole Cantica.