Floors. it up two or three times a year, instead of once. A dirty carpet literally infects the room. And if you consider the enormous quantity of organic matter from the feet of people coming in, which must saturate it, this is by no means surprising. As for walls, the worst is the papered wall; the next worst is plaster. But the plaster can be redeemed by frequent lime-washing; the paper requires frequent renewing. A glazed paper gets rid of a good deal of the danger. But the ordinary bed-room paper is all that it ought not to be. Papered, plastered, oil-painte [Pg 51] The close connection between ventilation and cleanliness is shown in this. An ordinary light paper will last clean much longer if there is an Arnott's ventilator in the chimney than it otherwise would. The best wall now extant is oil paint. From this you can wash the animal exuvi. These are what make a room musty.

The best wall for a sick-room or ward that could be made is pure white nonabsorbent cement or glass, or glazed tiles, if they were made sightly enough. Best kind of wall for a sick-r Air can be soiled just like water. If you blow into water you will soil it with the animal matter from your breath. So it is with air. Air is always soiled in a room where walls and carpets are saturated with animal exhalations. Want of cleanliness, then, in rooms and wards, which you have to guard against, may arise in three ways. 1. Dirty air coming in from without, soiled by sewer emanations, the evaporation from dirty streets, smoke, bits of unburnt fuel, bits of straw, bits of horse dung.

Dirty air from without. If people would but cover the outside walls of their houses with plain or encaustic tiles, what an incalculable improvement would there be in light, cleanliness, dryness, warmth, and consequently economy. The play of a re-engine would then effectually wash the outside of a house. This kind of walling would stand next to paving in improving the health of towns. Best kind of wall for a house

2. Dirty air coming from within, from dust, which you often displace, but never remove. And this recalls what ought to be a sine qu non. Have as few ledges in your room or ward as possible. And under no pretence have any ledge whatever out of sight. Dust accumulates there, and will never be wiped off. This is a certain way to soil the air. Besides this, the animal exhalations from your inmates saturate your furniture. And if you never clean your furniture properly, how can your rooms or wards be anything but musty? Ventilate as you please, the rooms will never be sweet. Besides this, there is a constant degradation, as it is called, taking place from everything except polished or glazed articlesE.g., in colouring certain green papers arsenic is used. Now in the very dust even, which is lying about in rooms hung with this kind of green paper, arsenic has been distinctly detected. You see your dust is anything but harmless; yet you will let such dust lie about your ledges for months, you