The Second Class of Tertullian's works, is that which includes his treatises against the heresies of his times. In these, the genius of our author is brilliantly illustrated. Here, we venture a remark on the ambiguity of the expressions concerning our author's Montanism. In the treatise against Marcion, written late in his career, Tertullian identifies himself with the Church and strenuously defends its faith and its apostolic order. In only rare instances does his weakness for the "new prophecy" crop out, and then, it is only as one identifies himself with a school within the church.