tenth centuries, pestilence and famine accelerated the extinction of predial slavery by weakening the numbers of the free population. 'History,' we are told by that thoroughly competent authority, Mr. Finlay, 'affords its testimony that neither the doctrines of Christianity, nor the sentiments of humanity, have ever yet succeeded in extinguishing slavery, where the soil could be cultivated with profit by slave labour. No Christian community of slave-holders has yet voluntarily abolished slavery. In no country where it prevailed has rural slavery ceased, until the price of productions raised by slave labour has fallen so low as to leave no profit to the slave-owner.' The moral of all this is the tolerably obvious truth, that the prosperity of an abstract idea depends as much on the medium into which it is launched, as upon any quality of its own. Stable societies are amply furnished with force enough to resist all effort in a destructive direction. There is seldom much fear, and in our own country there is hardly any fear at all, of hasty reformers making too much way against the spontaneous conservatism which belongs to a healthy and well-organised community. If dissolvent ideas do make their way, it is because the society was already ripe for dissolution. New ideas, however ardently preached, will dissolve no society which was not already in a condition of profound disorganisation. We may be allowed just to point to two memorable instances, by way of illustration, though a long and elaborate discussion would be needed to bring out their full force. It has often been thought since, as it was thought by timorous reactionaries at the time, that Christianity in various ways sapped the strength of the Roman Empire, and opened the way for the barbarians. In truth, the most careful and competent students know now that the Empire slowly fell to pieces, partly because the political arrangements were vicious and inadequate, but mainly because the fiscal and economic system impoverished and depopulated one district of the vast empire after another. It was the break-up of the Empire that gave the Church its chance; not the Church that broke up the Empire. It is a mistake of the same kind to suppose that the destructive criticism of the French philosophers a hundred years ago was the great operative cause of the catastrophe which befel the old social régime. If Voltaire, Diderot, Rousseau, had never lived, or if their works had all been suppressed as soon as they were printed, their absence would have given no new life to agriculture, would not have stimulated trade, nor replenished the bankrupt fisc, nor incorporated the privileged classes with the bulk of the nation, nor done anything else to repair an organisation of which every single part had become incompetent for its proper function. It was the material misery and the political despair engendered by the reigning system, which brought willing listeners to the feet of the teachers who