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 



505 



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 



