§ 1.  Catechesis.  The term “Catechesis” in its widest sense includes instruction by word of mouth on any subject sacred or profane Acts xviii. 25; xxi. 21, 24; Rom. ii. 18; Gal. vi. 6.  Cf. Clem. Alex. Fragm. § 28:  οὐκ ἔστι πιστεῦσαι ἄνευ κατηχήσεως., but is especially applied to Christian teaching, whether of an elementary kind appropriate to new converts, or, as in the famous Catechetical School of Alexandria, extending to the higher interpretation of Holy Scripture, and the exposition of Christian philosophy.