To explain clearly the distinction he made between the ethical and cosmic processes. Huxley, in the prefatory essay ("Prolegomena") published in the volume with his Romanes lecture, developed the analogy of a cultivated garden reclaimed from surrounding wild nature. He described how the countryside, visible from his windows at Eastbourne, had certainly been in a "state of nature" about two thousand years ago when Cæsar had set foot in Britain and had made the Roman camps, the remains of which still mark the chalk downs of England. "Except, it may be, by raising a few sepulchral mounds, such as those which still, here and there, break the flowing contours of the Downs, man's hands had made no mark upon it; and the thin veil of vegetation which overspread the broad-backed heights and the shelving sides of the coombs was unaffected by his industry. The native grasses and weeds, the scattered patches of gorse, contended with one another for possession of the scanty surface soil; they fought against the droughts of summer, the frosts of winter, and the furious gales, which swept with unbroken force, now from the Atlantic, and now from the North Sea, at all times of the year; they filled up, as they best might, the gaps made in their ranks by all sorts of overground and underground ravagers. One year with another, an average population, the floating balance of the unceasing struggle for existence among the indigenous plants, maintained itself. It is as little to be doubted that an essentially similar state of nature prevailed in this region for many thousand years before the coming of Cæsar; and there is no assignable reason for denying that it might continue to exist through an equally prolonged futurity except for the intervention of man." This present state of nature, he explained, is only a fleeting phase of a process that has gone on for millions of years. Under the thin layer of soil are the chalk cliffs, hundreds of feet thick and witnesses of the entirely different phases of the struggle that went on while the cliffs were being formed at the bottom of the chalk sea, when the vegetation of the nearest land was as different from the existing vegetation as that is different from the trees and flowers of an African forest. "Before the deposition of the chalk, a vastly longer period elapsed, throughout which it is easy to follow the traces of the same process of ceaseless modification and of the same internecine struggle for existence of living things; and when we can go no further back, it is not because there is any reason to think we have reached the beginning, but because the trail of the most ancient life remains hidden or has become obliterated." The state of nature, then, is a fleeting and impermanent process.