39. Porphyry, _De Abstin._, II, 37-43, expounds a theory about the demons, which, he says, he took from "certain Platonists" ([Greek: Platonikoi tines], Numenius and Cronius?). That these authors, whoever they were, helped themselves freely to the doctrines of the magi, seems to appear immediately from the whole of Porphyry's exposition (one could almost give an endless commentary on it with the help of the Mazdean books) and in particular from the mention that is made of a power commanding the spirits of evil (see _supra_, n. 37). This conclusion is confirmed by a comparison with the passage of Arnobius cited above (n. 36), who attributes similar theories to the "magi," and with a chapter of the Ps.-Iamblichus (_De mysteriis_, III, 31) which develops analogous beliefs as being those of "Chaldean prophets."--Porphyry also cites a "Chaldean" theologian in connection with the influence of the demons, _De regressu animae_ (Aug., _Civ. Dei_, X, 9). I conjecture that the source of all this demonology is the book attributed to Hostanes which we find mentioned in the second century of our era by Minucius Felix, St. Cyprian (_supra_, n. 38), etc.; cf. Wolff, op. cit., p. 138; _Mon. myst. Mithra_, I, p. 33. As a matter of fact it would be false logic to try to explain the evolution of demonology, which is above everything else religious, by the development of the philosophic theories of the Greeks (see for instance the communications of Messrs. Stock and Glover: _Transactions of the Congress of {268} History of Rel._, Oxford, 1908, II, pp. 164 ff.). The influence of the popular Hellenic or foreign ideas has always been preponderant here; and the Epinomis, which contains one of the oldest accounts of the theory of demons, as proved _supra_, n. 34, was influenced by the Semitic notions about genii, the ancestors of the _djinns_ and the _welys_ of Islam. If, as we believe, the text of Porphyry really sets forth the theology of the magi, slightly modified by Platonic ideas based on popular beliefs of the Greeks and perhaps of the barbarians, we shall be able to draw interesting conclusions in regard to the mysteries of Mithra. For instance, one of the principles developed is that the gods must not be honored by the sacrifice of animated beings ([Greek: empsucha]), and that immolation of victims should be reserved for the demons. The same idea is found in Cornelius Labeo, (Aug., _Civ. Dei_, VIII, 13; see Arnobius, VII, 24), and possibly it was the practice of the Mithra cult. Porphyry (II, 36) speaks in this connection of rites and mysteries, but without divulging them, and it is known that in the course of its history Mazdaism passed from the bloody to the bloodless sacrifice (_Mon. myst. Mithra_, I, p. 6). 40. Cf. Plutarch, _De defectu orac._, 10, p. 415 A: