Popular Science Monthly 



504 



which appears as heat and some of which 

 appears as motion. The body can be 

 thought of as an engine with steam up, 

 with the fires constantly burning while 

 life lasts. 



This fire keeps the body very close to a 

 temperature around 98 or 99 degrees 

 Fahrenheit, which is much above the 

 average outdoor temperature. 



Now with the fire con- 

 stantly burning, it is evi- 

 dent that heat is con- 

 tinually being given off. 

 Through the lungs the 

 gaseous products of 

 combustion, carbon di- 

 oxide (and along with 

 this a good deal of oxy- 

 gen also, for the body 

 uses only a part of the 

 oxygen that is breathed 

 in), are also constantly 

 thrown off. But the body 

 keeps its temperature con 

 stant by means of a wonder- 

 fully complicated temperature 

 control system. 



The Commission set about 

 studying the effect of • the 

 various factors of the air on 

 this heat eliminating, gas 

 producing, human engine by 

 placing people, as shown in 

 one of the accompanying pic- 

 tures, in a specially built ex- 

 periment chamber, a room 

 connected with steam coils, a 

 refrigerating plant, moisture 

 producing apparatus, ventil- 

 ating fans and various other 

 devices for altering the condi- 

 tion of the air. The great advantage of 

 this experiment chamber over the ordinary 

 room is that each of the various air 

 factors — temperature, moisture, etc. — can 

 be controlled and varied at will. . In a 

 crowded theater, for instance, .as the air 

 gets warmer it also gets more moist and 

 begins to have a "crowd" odor. In the 

 experiment chamber the temperature can 

 be hotter while the moisture remains the 

 same, or the moisture can be increased while 

 keeping the temperature the same. In this 

 way each of these various factors can be 

 separated and studied independently. 



The Commission paid people regular 

 salaries to stay irt this experiment chamber. 

 First these people, or subjects, would be 

 exposed to one condition for a day or a 



Measuring the size of the 

 breathing spaces in the 

 nostrils by breathing gently 

 on a cold metal plate 



The overheated air in the 

 room has caused the bone 

 in one nostril to swell 



week and then to another. They wrote 

 down on paper just how they felt. But 

 their opinions on personal comfort were not 

 sufficient. It is also desirable to know 

 whether people can do better work under 

 one condition than they can under another, 

 not merely physical work, but mental 

 work. And are they as healthy in 

 one condition as they are in 

 another? Is it variations in 

 temperature that have the 

 greatest influence on 

 health and efficiency? 

 Is it variations in mois- 

 ture? 



Nearly four years 

 have been spent in 

 getting the answers to 

 these most important 

 questions. Over two 

 hundred different peo- 

 ple — men and women, col- 

 lege students, clerks, typists, 

 truck drivers, boiler makers, 

 firemen, the robust and the 

 weak, the large and the small, 

 the clean and the unclean, 

 have spent some portion of 

 their time — from one day to 

 six weeks — within the experi- 

 ment chamber. To observe 

 and study the effects of the 

 various air factors on these 

 subjects the Commission has 

 employed a corp of trained 

 observers, — psychologists, 

 physicians, physiologists, 

 chemists, sanitarians, bacteri- 

 ologists, and engineers who 

 have recorded with scientific 

 exactness each shade of differ- 

 ence observed in the separate individuals. 



The Findings of the Jury of Specialists 



In the first place, they have found that 

 so long as the room was kept cool, that 

 so long as the temperature was not allowed 

 to rise, it did not make much difference 

 whether or not a plentiful supply of fresh 

 air was supplied to the chamber. 



Even when the subjects spent a whole 

 day and six days in succession in the 

 unaired chamber, breathing air that con- 

 tained the accumulated products of the 

 breath, they did as good mental work, felt 

 just as happy, and did as much physical 

 work as they did when the ventilating fans 

 were constantly changing the air. Further- 

 more, the most careful observations of the 



