the evil was met by an increase in the dose of the very remedy which aggravated it—useless expenditure in the cities, ruinous taxes on agriculture. Matters went from worse to worse, until the system reached the limit of its elasticity, and the whole social fabric collapsed in a colossal catastrophe. This is precisely the mistake which modern civilisation must learn to avoid. The catastrophe of the Roman Empire teaches us moderns one lesson: and that is, that the evil from which the great cities of the civil world are suffering at present is a salutary, health-giving, and beneficent visitation. For it puts a natural brake on the growth of cities and of their luxury, and keeps the population in the fields, where the rise in the price of living brings profit, greater comfort, and improved living in its train. It is, in short, the _vis medicatrix naturæ_, which tends to restore the balance between agriculture and industry, between the city and the country, a balance which the development of modern civilisation has upset. Therefore all the artificial measures which pretend to mitigate this evil, at the very moment when the force of circumstances demands that this development shall stop, must be pernicious. While they tide over a trifling evil of the moment, they lay up for the future troubles and difficulties and dangers of infinitely greater gravity. Even if modern civilisation adopted in its entirety the policy pursued by the Roman Empire, and tried to eradicate the evil with the same deadly artificial measures which only aggravated it, there would still doubtless be no ground for fearing a catastrophe in the future analogous to that which overwhelmed Greco-Roman civilisation. Modern civilisation is too vast, too powerful, too deep-rooted, to have any fear of a similar fate. But if not destroyed, modern civilisation might be profoundly shaken and weakened in the event of its imitating the policy of Rome and seeking to favour the cities overmuch at the expense of the country;—all the more shaken and weakened, because, dazzled as we all are by the triumphs of the world in which we live, and by the surface marks of its powers and grandeur, it is much more difficult for us than it was for the ancients in a similar case to discern the signs of old age in it, and the cracks which are spreading in the edifice in which we live.