Now, a most important question is, Where does the waste-pipe go to ? In almost all old houses in London the waste-pipe, even if the cistern be at the top of the house, goes straight down through the house into the drain below. It does so in many new houses, and when it does not actually do that, it very often goes into one of the pipes leading into the drain.

Now, the cistern is commonly covered over, and rightly so, to keep it free from dust, and so you see the air over the water in the cistern is placed in direct communication by the waste-pipe with the air in the drain ; and in a very laTge number of houses the only way that the foul air can get out of the drain at all is by getting up the waste-pipe of the cistern, and so the foul matters are absorbed by the drinking water, and it becomes foul and unfit to drink, the result being disease in the household. I am convinced that the greater proportion of cases of typhoid fever in London are caused by the air of the drain getting into the drinking water cistern.

How can this be prevented ? It can be avoided by making the waste-pipe end anywhere except in the drain. It does not matter much where it ends. It is only of use when there is something wrong with the ball-cock, so that the water overflows, or when it is necessary to clean out the cistern, which is done by taking out that part of the pipe which stands up in the cistern, letting the water run away, and then cleaning the cistern out down the waste-pipe. This pipe should be made to end somewhere out of doors-say over the yard or over the top of a rain water-pipe, or on the leads or the roof. Take it straight through the wall, and let it end in the open air.

Sometimes, instead of a waste-pipe of that kind, an opening is merely made in one side of the cistern above the level of the water, and then if the water ever rises up to that it flows over on to the roof or on the leads, and if the cistern is out on the leads this is all that is necessary.

I have seen sometimes, with a cistern out of doors upon the leads, the waste-pipe taken through the bottom, down through the rooms below, through the basement, and into the drain or sewer below the house.

There is a cistern which is called the self-cleansing cistern, the bottom of which slopes in all directions towards the middle point, and at that point the waste-pipe is placed, and it is a waste-pipe that can be lifted. At or just above the level of the water when the cistern is full, there are holes in the waste-pipe, so that whenever the water rises higher than it should be it flows away through the holes down the waste-pipe. By means of a lever, which is fixed to the waste-pipe above the cistern, the pipe can be raised out of the socket in which it fits, and then all the water runs out of the cistern, and as the bottom of the cistern slopes towards the aperture in the middle, the water flowing away washes out any sediment there may be.

It is now a very common practice to have a filter in the cistern to prevent suspended particles in the water from being drawn off at the tap, but I must tell you that most of these filters do very little else than prevent suspended matters from getting into the water drawn, because they cannot be sufficiently aerated. There is one disadvantage to this plan, and that is, that whenever the tap is turned on, there is a suction of water towards the filter, and the suspended matters in the water get attached to the outside of the filter. In some the water is made to pass through a piece of sponge, which, after a time, becomes full of impurities, and the water is worse after passing through it than before.

There is a device by which the water is admitted through a tap, carried down by means of a pipe into a circular space which is outside the filtering material, but yet separated from the water in the cistern, and passes out at another place, so that it continually washes the surface of the filter, while a certain portion of it passes through the filtering material, and so into the compartment from which filtered water is drawn by the tap.

There is another thing worth bearing in mind, and that is, that a filter in a cistern requires air, because, when you are drawing off water from the tap, you are drawing it off faster than water can come into the filtering material, so air is allowed to come in through an air-pipe into the filtering material Another advantage that that air-pipe has, is that the top of it can be connected with the water-tap, and so water can be driven by means of it through the filtering material, so as to cleanse it.

Among refuse matters that have to be removed from habitations there is first what is called dust. You know, in most of our large towns, it is collected in receptacles of some kind or another.

Two or three things to be said with regard to the place where these should be. In the first place, they ought not to be built against the walls of dwelling-rooms, as the rooms may be rendered unhealthy without being rendered damp, and I have known many dwelling-rooms rendered very unhealthy by the dustbins being built against their walls. The next thing is that nothing except ashes should be thrown into the dust-bin. All organic kitchen refuse ought to be burnt, and not allowed to accumulate If put into the dust-bin it certainly becomes a nuisance. It can be burnt if it be thrown on the kitchen fire the last thing at night, when the kitchen fire has just been allowed to go out and it will dry gradually during the night, and can then easily be burnt in the morning, and no kind of unpleasantness is caused if this is done regularly every day. It is as necessary also to remove refuse matters generally from the neighbourhood of habitations, as it is to get rid of refuse matters from our bodies.

We, as you know, are continually, separating out from our blood impurities, and we ought to as regularly get rid of all refuse matters from the neighbourhood of our dwellings.