a. =Apologetical and Controversial Treatises against Jews and Pagans=, which belong to his pre-Montanist period. The most important and instructive of these is the _Apologeticus adv. Gentes_, addressed to the Roman governor. A reproduction of this work intended for the general public, less learned, but more vigorous, scathing and uncompromising, is the treatise in two books entitled _Ad Nationes_. In the work _Ad Scapulam_, who as Proconsul of Africa under Septimius Severus had persecuted the Christians with unsparing cruelty, he calls him to account for this with all earnestness and plainness of speech. In the book, _De testimonio animæ_ he carries out more fully the thought already expressed in the _Apologeticus c. 17_ of the _Anima humana naturaliter christiana_, and proves in an ingenious manner that Christianity alone meets the religious needs of humanity. The book _Adv. Judæos_ had its origin ostensibly in a public disputation with the Jews, in which the interruptions of his audience interferes with the flow of his discourse. b. =Controversial Treatises against the Heretics.= In the tract _De præscriptione hæreticorum_ he proves that the Catholic church, because in prescriptive possession of the field since the time of the Apostles, is entitled on the legal ground of _præscriptio_ to be relieved of the task of advancing proof of her claims, while the heretics on the other hand are bound to establish their pretensions. A heresiological appendix to this book has been erroneously attributed to Tertullian (see § 31, 3). He combats the Gnostics in the writings: _De baptismo_ (against the Gnostic rejection of water baptism); _Adv. Hermogenem_; _Adv. Valentinianos_; _De anima_ (an Anti-Gnostic treatise, which maintains the creatureliness, yea, the materiality of the soul, traces its origin to sexual intercourse, and its mortality to Adam’s sin); _De carne Christi_ (Anti-Docetic): _De resurrectione carnis Scorpiace_ (an antidote to the scorpion-poison of the Gnostic heresy); finally, the five books, _Adv. Marcionem_. The book _Adv. Praxeam_ is directed against the Patripassians (§ 33, 4). In this work his realism reaches its climax at c. 7 in the statement: “_Quis enim negabit, Deum corpus esse, etsi Deus spiritus est? Spiritus enim corpus sui generis in sua effigie_,”--where, however, he is careful to state that with him _corpus_ and _substantia_ are identical ideas, so that he can also say in c. 10 _de carne Christi_: “_Omne quod est, corpus est sui generis. Nihil est incorporate nisi quod non est._”