The laws of health / by W.H. Corfield.

  • William Henry Corfield
Date:
1896
Catalogue details

Licence: Public Domain Mark

Credit: The laws of health / by W.H. Corfield. Source: Wellcome Collection.

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    tissues and setting the oxygen free into the air. It is the green parts of the plants that do this, and only in the daytime. The flowers of plants and ripening fruits, on the contrary, absorb oxygen and give out carbonic acid. It is, therefore, not advisable to keep plants, and especially flowering plants, in sleeping rooms. Air which has been once breathed is not fit to breathe again. It contains too much carbonic acid, far too little oxygen, is too moist and also con- tains a small quantity of foul organic matter. But carbonic acid gas, although a poisonous gas in itself, is not present in the air that is breathed out in sufficient quantity to produce any marked effect. It is the diminution of oxygen and the presence of foul matter in the air which has been breathed which makes it unfit to breathe again. In fact the amount of car- bonic acid is taken as the measure of the impurity of air that has been breathed because the other defects are proportional to it. Now expired air contains nearly 120 times as much carbonic acid as inspired air. On the average a man inspires and expires be- tween sixteen and seventeen cubic feet of air in an hour. Since then the air he expires contains about 120 times too much carbonic acid it will require about 120 times its volume of air to dilute it so that it shall be fit to breathe again—that is to say about 2,000 cubic feet: so that each person requires as much as 2,000 cubic feet of fresh air every hour. It is, how- ever, found practically that this amount is not suffi- cient to prevent the air of a room in which persons are breathing from becoming stuffy—the stuffiness being caused by the presence of the foul organic
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