Who that has ever felt the refreshing effects of the morning air, can wonder at the lassitude and disease that follow the continued breathing of the impure air of crowded or ill-ventilated rooms?

To prove how soon, and by what trifling means, impure air may be generated, we have only to go into a bedroom in the morning, soon after the occupant has left his bed, and immediately we shall find our sense of smelling offended by the odour of animal effluvia, with which the room is filled; and these are the effects, notwithstanding that the occupant may be perfectly healthy, and scrupulously cleanly, in his person. If, under such circumstances, the air is rendered impure, how much more injurious it must be when several persons are confined in one room; where, perhaps, domestic affairs are carried on, such as cooking and washing, and where the windows are made not to open, and the door is never opened but while some one is passing through it!

To be sensible of the bad effects of shutting out the pure air, it is only necessary to observe the countenances of those who inhabit close rooms and houses, the pallid hues of their skins, their sunken eyes, and their slow, languid

movements.

Besides the contamination of the air through breathing it over and over again, there are other matters which render the air impure;

these are the elements constantly passing off from the surface of animal bodies, the combustion of candles, and other lighted substances. There can be no general excuse for inattention to ventilation on the ground that fresh air cannot be obtained. By the incessant movement of the wind, and by the influence of vegetation, nature provides an ample supply; but it is very doubtful whether the largest portion of the community avail themselves of this blessing; whether they attend to the proper ventilation of their houses, or even attend to ventilation at all. If fresh air were composed of arsenic, a large portion of the people could not have more dread of introducing it into their houses, especially into their sleeping rooms. They have an idea that cold. air produces colds; nothing, however, can be more unfounded. Colds are improperly named, for they are fevers, and nothing else. Now, fevers are produced, not by cold air, not by fresh air, but by want of due exercise, a clean skin, and proper ventilation. ventilation. If fresh air be destructive, as those people imagine, who have not been taught its importance, God would not have provided the means for such an enormous supply. Whatever nature provides in large quantities, she intends for very general use. Among these, water, sunshine, and pure air are pre-eminent.

Persons are generally very particular about

drinking dirty water, but not at all about breathing dirty, impure air. Why is this? Simply because water is a fluid which they can see, and air is a fluid which they cannot see. This is, indeed, an exemplification of the old saying, that 'What the eye don't see, the heart don't grieve.' Yet, in reality, impure air is as injurious as impure water. Such persons, however, must be taught to understand distinctly, that there can be no health or vigour while such silly and blamable conduct be pursued, and that it is only by attending to the proper ventilation of their houses that these inestimable blessings can be secured.

A clever physician writing on this subject, remarks that, A necessary consequence of bad ventilation in the home is bad morality. In other words, fresh air is not only conducive to health and vigour, but to virtue and religion. For without pure air the richest food cannot nourish, the carbon of the blood cannot burn; consequently impure air induces thinness and coldness of the blood. Coldness of blood creates shivering and discomfort, and then again a craving for something that will light up throughout the body a feeling of warmth. The intoxicating cup readily presents itself, and for the sake of its short-lived, genial glow, many, alas! yield themselves to its fatal spell. So true is it that all efforts to improve the working classes must comprehend improvement

in the construction of their dwellings, that cleanliness is the handmaid of temperance and religion, and that sanitary reform, conducing alike to elevate the tone of public health and public morality, is not more a philanthropic act than a Christian duty.'

The Atmosphere-Ventilation, &c.

In order that the necessity of this important element of health, pure air, should be fully recognised, it will be necessary to explain the nature of the atmosphere which it is the object of ventilation to admit into the house, while that which is impure should be banished from it.

The word 'ventilation' is derived from the Latin word for 'wind.' Our earth is surrounded by an atmosphere of air, and though we can neither see, nor taste, nor grasp it, yet it is in reality a heavy substance. The atmosphere. is considered to be forty-five or fifty miles high, but the heavier part is close to the earth, and it rapidly becomes thinner and lighter in ascending, so much so that people experience great difficulty in breathing on the top of high

mountains.

The most important substances of which the atmosphere is composed are these:

1. Oxygen, a kind of air or gas without colour, taste, or smell. It is so important that, were it withdrawn, we could no longer exist;

without it, we could have neither light nor heat from coal, wood, or substances of the same kind.

2. Nitrogen; a kind of air resembling oxygen in its freedom from taste, colour, and smell, but a lighted candle is instantly extinguished in it, and animals cease to breathe when it alone is inhaled.

3. Carbonic acid, which is colourless, but has a slight smell and a sour taste. There is but a small proportion of carbon in the atmosphere, for this wise reason that it is poisonous to animals. It is, however, as necessary to vegetable as oxygen is to animal life; if there were no carbonic acid at all, vegetable life would cease.

4. Watery vapour, or the steam, sometimes visible, sometimes invisible, which ascends from all surfaces of water, becomes part of the atmosphere, and is necessary to the life of plants and animals.

Although three of the principal substances of which the atmosphere is composed cannot be breathed alone, without destroying or endangering life, yet so beautifully combined and arranged are they, that the air which is thus formed is one of the most blessed gifts of the Creator. Animal life is so constituted, however, that it is for ever rendering impure and poisonous this fresh and healthy substance.

There is an apparatus within the living man