Hygeia, then, is a city for a hundred thousand inhabitants. (The main principles could be worked out in a much smaller community, but in a less complete form.) It has twenty thousand houses on an area of four thousand acres of ground: apparently rather densely populated, but not too much so when good sanitary arrangements are adopted. There are no very lofty houses. In busy thoroughfares, where shops are required, there are three stories or floors over the shops; and some of the best streets in private or 'west-end' neighbourhoods have four stories in all; but in others the general number is three. Underground living-rooms and kitchens there are none; instead of these, every house is built upon arches of brickwork, which form channels of ingress for fresh air, and of egress for all that is required to be got rid of. Running along beneath each main street is a railway for the transport of heavy commodities. All the streets are wide enough to admit plenty of cheerful sunlight and fresh air, and rows of trees are planted between the foot-ways and carriage-ways; the carriage-ways are paved with wood set in asphalt, and the foot-ways with stone pavements ten feet wide. Tramways are not permitted, as they cut up the roadway; omnibuses above ground and railways below will suffice instead. All the interspaces between the backs of the houses are laid out as gardens. Churches, hospitals, theatres, banks, lecture-rooms, and other public or large buildings, follow the same alignment as the houses in the streets, but all detached; and every one flanked by a garden-space, however narrow. There is no occasion for those unsightly concomitants of London sanitation, scavengers' carts. The accumulation of mud and dirt in the streets is washed away every day through side-openings into subways, and is with the sewage conveyed to a destination apart from the city; there are neither gratings nor open drains; and there are no 'gutter children,' because there are no gutters for children to paddle and dabble in, and because we may hope that, eventually, 'young Arabs' will disappear from our towns.