Popular Science Monthly
��heart and circulation and the general condition of the body failed to show any harmful effects. The only indication of any depressing effect of breathing this confined and several times used air was that about five per cent less food was eaten.
The decreased appetite was not due to any accumulation of the gas carbon di- oxide; for, when large quantities of carbon dioxide from a tank were added to the fresh air being blown into the room, the appetite was not reduced at all. It is im- probable that any poison from the breath affected the appetite, for many elaborate experiments on this point have failed to show the existence of any such poison in the human breath. It is possible that what affected the appetite adversely was a slight odor of sweaty clothes or decaying teeth, which odors are the natural out- come of the continued oc- cupancy of an u nventilated room.
The above statement should be care- fully scruti- nized and re- read. This finding does not mean that fresh air is of no value. Fresh air is of the utmost value, as can be shown by a wealth of examples. Whut this does imply is that the good ef- fects of fresh air are due more to one of its components — cool temperature — than to another com- ponent, chemical purity. Conversely, this finding indicates that the unrefreshened air of an occupied room whose temperature is not allowed to get too high, does not produce unfavorable effects on the mind, the comfort, or the various organs of the body.
On the other hand, that this re-breathed air, even though cool, is not entirely with- out some effect, is indicated by the fact that the subjects unconsciously ate slightly
���Testing the pulse and blood pressure of workers and of reclining subjects under the same air conditions
less. In this connection it should be borne in mind that in producing even this slight effect on the appetite the accumulation of re-breathed air in this experiment chamber was from three to twelve times as great as that found in an ordinary badly ventilated schoolroom.
Compare this experience as to re- breathed air with the effects produced by over-heating, even slight over-heating; that is, an increase of temperature from 68 to 75 degrees. At these temperatures, and with the subjects dressed for fall or winter weather, the heart beats faster; the body cannot get rid of its heat as readily and the heat accumulates thereby, causing the body temperature to rise sometimes a degree or more. The subjects feel uncom- fortably warm; they do less physical work. One experi- ment showed 15 percent less work done at 75 than at 68 degrees. The appetite, how- ever, remained about the same and the mental work was un- affected even by air hot enough to cause profuse perspiration and very evi- dent discom- fort.
As compared with the chem- ical purity of the air, then, the variations in temperature have been found to pro- duce a very much more pronounced effect.
The Nose Is a Pretty Good Judge
Now, in addition to these effects, over- heated air, or air which is warm enough to cause people, as they are dressed, to feej uncomfortably warm, also produces a very evident effect on the nose. There is a most peculiar spongy bone in each nostril, called the turbinate bone. This bone has the power of expanding or contracting. When it contracts so as to occupy very little space there is a wide clear passage to