Though of ages so unequal, "S. S." and "C. E." are sisters. Both are international and interdenominational. Both apply the principle of age classification to religious work. Both are strongly evangelical, and earnest seekers of souls. Both are held in strictest subordination to the church. And both are Bible lovers; for the Christian Endeavor pledge requires daily reading of the Bible, and the weekly prayer-meeting topic calls out no slight amount of Bible study. Moreover, this topic is usually in line with the week's Sunday-school lesson,--not the same as the latter, but suggested by it. The two agencies are at work in different fields. The one puts in, the other draws out. The one studies, the other practices. The Christian Endeavor society affords an excellent test for the Sunday-school, and is its complement. Whatever helps the one aids the other, and the two should labor hand in hand. There are even some things that the Sunday-school might learn from its little sister. The principle of the pledge has proved attractive and powerful in the Christian Endeavor society. Why not adopt it in the Sunday-school, asking the scholars for voluntary vows that they will attend regularly and will spend fifteen minutes a day in studying their lessons? The monthly consecration meeting maintains wonderfully the spirituality, zeal, and discipline of the Christian Endeavor society. Why not a monthly consecration and experience meeting of Sunday-school teachers? Three or four Christian Endeavor societies cannot exist in the same town without forming a local union for mutual encouragement and consultation. Sunday-schools have their county conventions, but why not also this beautiful interdenominational fellowship among the Sunday-schools of every community? A large part of the remarkable success of Christian Endeavor is due to its being a work of the young people for themselves. There is close pastoral and church supervision, and it is welcomed; but the Endeavorers feel that it is their society, for whose honor they are responsible, and whose victories depend upon themselves. As far as possible, this spirit should be incorporated in the Sunday-school, so that the Bible study may not seem a work impressed on the scholars, but elected by them,--_their_ work, and not their teachers'. How can the Christian Endeavor society help the Sunday-school? Greatly in its prayer-meetings, by remembering the allied Sunday-school topic of the morning. Here is a chance for the teacher to enlarge upon some theme treated too hurriedly in the lesson hour, and for scholars to show their appreciation of their teacher by repeating some thought he brought out in the morning. If rightly managed, the Christian Endeavor meeting furnishes an admirable opportunity for advertising the Sunday-school, and practically applying the truths there taught.