And as to the imperfect reception of Christianity in some places and times, and its actual retrogression, as from the Mohammedan conquest, in others; is it not plain that we have to expect Christianity to advance by moral means and not by mechanical? Christ left a leaven in the world, that it might work and leaven mankind. We are apt to expect that it should work by magic, and not by its own moral influence. Now, our Lord never so worked on earth. If He worked in His miracles by a mechanical force on nature, He never applied such a force to human wills, nor does His Gospel work so now in the world. He called His church the salt of the earth; but He warned it that the salt might lose its savour. He said it was a grain of mustard seed, which should grow into a tree and fill the earth; but He never said that there should be no blights, no frosts, no tempests which might check its growth, or nip its leaves or rend off its branches. The apostles themselves knew that they had the Gospel treasure in earthen vessels, and when the vessel was injured the treasure could not be safely conveyed by it. It is very natural to expect that a potent remedy should produce an instantaneous cure. But we are constantly taught by experience that maladies are too deep-seated, or constitutions too sickly, for rapid or perfect restoration. We naturally expect every man under the true influence of Christianity to become perfect: we expect Christianized society to exhibit no defects. But, in reality, we only find that both the man and the people have a new principle, which gradually raises them, that they become instinct with a new life, which shows itself sometimes indeed by vigorous action, but which sometimes, too, becomes languid and feeble. If we make these allowances, there will be nothing to stagger our faith in the slow progress of the Gospel through the world. In the beginning, Christianity was thrown into mortal conflict with heathenism. That heathenism it steadily extirpated, whilst the sounder philosophy which had lived in the midst of heathenism it adopted for its own. In the midst of this there came too often an attempt at compromise. There sprang up a fusion between Christian verity and philosophy, and philosophy, too, of the corrupter heathen type, not of the purest or most divine type. Hence the strange forms of heresy which meet us in the earlier centuries. After the barbarian conquests, Christendom indeed took its fierce captors captive. They who had trod down imperial Rome, bowed lowly before Him whom Roman governors had crucified and Roman emperors had persecuted. Then came a struggle between barbarism and faith, the faith gradually subduing the barbarism, but the barbarism still clouding the faith. And I think we do not enough remember how through the Middle Ages, on which we often look so contemptuously back, there was ever going on a great mission work of the church and of the Gospel, the fierce barons and the rude