MH page 274

The lungs are constantly throwing off impurities, and they need to be constantly supplied with fresh air. Impure air does not afford the necessary supply of oxygen, and the blood passes to the brain and other organs without being vitalized. Hence the necessity of thorough ventilation. To live in close, ill-ventilated rooms, where the air is dead and vitiated, weakens the entire system. It becomes peculiarly sensitive to the influence of cold, and a slight exposure induces disease. It is close confinement indoors that makes many women pale and feeble. They breathe the same air over and over until it becomes laden with poisonous matter thrown off through the lungs and pores, and impurities are thus conveyed back to the blood.

Thorough ventilation is necessary because close, ill-ventilated indoor spaces weaken the system and induce disease. The paragraph asserts a causal relationship between indoor confinement in vitiated air and increased disease susceptibility.

In the construction of buildings, whether for public purposes or as dwellings, care should be taken to provide for good ventilation and plenty of sunlight. Churches and schoolrooms are often faulty in this respect. Neglect of proper ventilation is responsible for much of the drowsiness and dullness that destroy the effect of many a sermon and make the teacher's work toilsome and ineffective.

Buildings must be constructed with good ventilation and sunlight to prevent drowsiness and dullness. The text links inadequate building ventilation directly to human fatigue and reduced cognitive effectiveness.

So far as possible, all buildings intended for human habitation should be placed on high, well-drained ground. This will ensure a dry site and prevent the danger of disease from dampness and miasma. This matter is often too lightly regarded. Continuous ill-health, serious diseases, and many deaths result from the dampness and malaria of low-lying, ill-drained situations.

Habitations should be built on high, well-drained ground to avoid dampness, miasma, and subsequent disease. The text asserts a direct empirical link between low, damp building sites and chronic illness or death.

In the building of houses it is especially important to secure thorough ventilation and plenty of sunlight. Let there be a current of air and an abundance of light in every room in the house. Sleeping rooms should be so arranged as to have a free circulation of air day and night. No room is fit to be occupied as a sleeping room unless it can be thrown open daily to the air and sunshine. In most countries bedrooms need to be supplied with conveniences for heating, that they may be thoroughly warmed and dried in cold or wet weather.

Houses require thorough ventilation and sunlight in every room, particularly sleeping areas. The text makes specific empirical claims regarding the necessity of air circulation and sunshine in rooms for health.