This is one of the vexed subjects of the age; though it must be understood that the great differences of opinion only take place as to the means and methods by which it is attempted to get rid of evils, which, one and all agree, exist in a greater or less degree, in connection with the dwellings which belong to the present decade.

Rapid strides have of late years been made in the various details of sanitation, which have required great and wholesale improvement; and still there is ample room for further advancement in all its branches.

Many defects have 'been got rid of by sure and proved remedies, but there remain many more, which have not been dealt with in such a manner that the world can say we have reached a point of success more or less short of perfection; and it is on these varied and contradictory theories that there is this great amount of disagreement among authorities on sanitation; for the patents and so-called remedies put forth are too numerous to mention. Therefore it is only the wish of the writer to put before the students those things which, we all know, require alteration for the better, so that any suggested methods hereinafter given must not be taken "as recommended"; they are only advanced to give the student an idea how such results might be attained.

The various circumstances, and his own well-considered practical opinion, ought to decide him as to whose patent and what remedy are to be used for particular difficulties. It would be invidious of the author to advertise any one or another person's special patented ideas.

The Model Dwelling

A "model dwelling," to be up to the requirements of the age and of a healthy life, should be one containing sufficient cubic contents, area, and light for the purposes required; with a plentiful supply and constant circulation of pure air, cooled in summer and warmed in winter, without any approach to draughts of any kind, which would affect prejudicially the health and comfort of the inmates.

It should also be provided with a plentiful supply of good pure water; and the sanitary conveniences, of whatever kind, should be so arranged that no bad smells or offensive odours can possibly be emitted, except, as it were, out of the reach of humanity. All drains should be air-tight and water-tight, well and securely trapped, laid with proper gradients, and provided with adequate ventilation, so that a body of pure air, Fig.uratively speaking, may prevail within the appliances, and so that all foul air may be driven out, from point to point, at such places that it is harmless to life.

It must be understood that foul air is lighter than pure air, and for that reason invariably floats, as it were, on the top of the pure air, so that we know where it collects, and therefore have to remove it from the upper part of any apartment, where it accumulates. Pure air is fouled or polluted by carbonic acid, which either comes, by the breath, from the lungs, or is emitted from the skin of human beings or animals.

Pure air is also vitiated by sewer gas and bad smells, and by combustion, whether caused by fires, gas, or other means of lighting and warming.

On the other hand, leaves of trees and other forms of vegetation absorb the carbonic acid out of the foul air, and generally act as a sort of purifier and filter to the atmosphere.

For the sake of convenience it will be as well to subdivide the subject of sanitation under two heads, as follows: a. Drainage and its Connections.

1 Air and Ventilation.