’Tis an old proverb that “prevention is better than cure;” yet how few there are who practically believe it. The principle embodied in this proverb received the approval and sanction of past ages, but which it is most difficult to enforce at the present time; it may be explained by the fact, that men not being forewarned cannot be forearmed, and further, because another principle which is expressed in the words, “men think all men mortal but themselves,” lies deep in the human mind. The blessing of health is not valued till it is lost. Let the mysterious hand of disease touch us, and we throb with painful anguish. Then do we long most earnestly for our valued health and strength; we resolve that once well again we will adopt such regulations and precautions as shall ensure a continuance of the invaluable blessings of health: such is the reasoning of the sick and afflicted. To the invalid the quantity and quality of the air he breathes is of vital importance, but to the man in comparative health, it is a matter of indifference. The laws which regulate the diffusion of gases on which ventilation depends, or the action of pure or impure air on the animal economy, is to him a subject of indifference; it does not yet affect him, and he has enough to do without it. The subject of ventilation bears such an important relation to health, and health is one of the greatest blessings of life, that I conceive it to be the duty of all to be fully alive to its value. In these days when the schoolmaster is abroad, and the march of intellect so rapid, it is not a little remarkable that the knowledge of the laws of health, based upon scientific data, are so little known.