The houses of stationary peoples become more and more firm and stable. At first they are built of earth and wickerwork, later of stone, and finally of bricks, as among the Babylonians. Foundations are invented, dwellings are accurately designed as to line and angle; the curved line is introduced, bringing with it arches both round and pointed, as may be seen in the remains of Roman and Etruscan buildings. The structure is adorned, and it becomes a work of art. But man also dwelt over the water, sometimes erecting his habitations upon rafts and floats, often upon structures that rose from beneath the surface. Thus was he, dwelling in communities of various sizes, secure from the attacks of land enemies. Even to-day there are uncivilised peoples who live over water, constructing their homes upon piles. [Sidenote: Taming of the Wild] Clothing, however, was invented partly that in cold climates men might survive the winter, partly for the sake of ornament. In tropical regions man originally had no knowledge of the necessity for clothing: garments are masks, disguises; they bear with them a charm; they are the peculiar property of the medicine-men or of those who in the religious dance invoke the higher powers. Modesty is a derived feeling; it cannot exist until a high state of individualisation has been attained, until each man desires exclusive possession of his wife, and therefore wishes to shield her from the covetousness of other men. With the knowledge of dress, a desire for adornment, the effort to assist Nature in producing certain definite æsthetic effects, arises. Less uniformity in the appearance of the body is wanted, and this brings tattooing and the use of ornament into vogue. Later there is a fusing of these several aims; clothing becomes protection, veil, and ornament in one, fulfilling all three functions at the same time. Another epoch-marking discovery, often arrived at while races are still in the state of subsistence by hunting, is the domestication of animals. This may have originated in the practice of provoking one beast to attack another in order to vanquish them both the more easily. Further development, bringing with it the idea of totemism and the notion that the soul of an animal dwells in man, drew him nearer to his animal neighbours; and he sought them out as comrades and attendants. The taming of wild creatures arose from two sources--human egoism, and the innate feeling of unity and identification with Nature common to all savages; hence on the one hand, the subjugation of animals, and, on the other, their domestication. Neither employment rendered it by any means less possible for men to hold animals in reverence, or to attribute to them virtue as ancestral spirits.