The original authorities of the life of Constantine are Eusebius, Bishop of Caesarea, his friend and admirer; also Hosius, of Cordova. The ecclesiastical histories of Socrates, Theodoret, Zosimus, and Sozomen are dry, but the best we have of that age. The lives of Athanasius and Arius should be read in connection. Gibbon is very full and exhaustive on this period. So is Tillemont, who was an authority to Gibbon. Milman has written, in his interesting history of the Church, a fine notice of Constantine, and so has Stanley. The German Church histories, especially that of Neander, should be read; also, Cardinal Newman's History of the Arians. I need not remind the reader of the innumerable tracts and treatises on the doctrine of the Trinity. They comprise half the literature of the Middle Ages as well as of the Fathers. In a lecture I can only glance at some of the vital points. PAULA. * * * * * A.D. 347-404. WOMAN AS FRIEND. The subject of this lecture is Paula, an illustrious Roman lady of rank and wealth, whose remarkable friendship for Saint Jerome, in the latter part of the fourth century, has made her historical. If to her we do not date the first great change in the social relations of man with woman, yet she is the most memorable example that I can find of that exalted sentiment which Christianity called out in the intercourse of the sexes, and which has done more for the elevation of society than any other sentiment except that of religion itself. Female friendship, however, must ever have adorned and cheered the world; it naturally springs from the depths of a woman's soul. However dark and dismal society may have been under the withering influences of Paganism, it is probable that glorious instances could be chronicled of the devotion of woman to man and of man to woman, which was not intensified by the passion of love. Nevertheless, the condition of women in the Pagan world, even with all the influences of civilization, was unfavorable to that sentiment which is such a charm in social life.