184 



SCIENCE 



[N. S. Vol. XLIV. No. 1128 



cent. For a period of two and one quarter 

 hours the door of the chamber was kept 

 closed, although it was not wholly air-tight, 

 and the unusual atmospheric conditions 

 were maintained, although not continually 

 at their maximum. Afterward the door of 

 the chamber was opened and the air within 

 was allowed to acquire the more comfort- 

 able conditions of the room air outside, 

 which possessed a temperature of 18° C. 

 (64.5° F.) and a relative humidity of 51 

 per cent. During the whole time of the 

 experiment a continuous record was made 

 of the subject's bodily temperature; at 

 intervals of fifteen minutes measurements 

 were made of the temperature and the 

 humidity of the air of the chamber, of 

 the temperature of the subject's mouth and 

 of the skin of his forehead, and of the 

 rate of his pulse and his respiration; at 

 intervals of every hour his systolic and dias- 

 tolic blood pressures and the carbon diox- 

 ide content of his alveolar air were deter- 

 mined; while occasional records were made 

 of the carbon dioxide content of the air of 

 the chamber and of the subject's sensa- 

 tions. The results of the experiment will 

 be discussed later. It is typical of many 

 experiments, similar in object although 

 differing in details, which have been per- 

 formed in recent years inside and outside 

 many laboratories in an endeavor to dis- 

 cover the relations of the individual to the 

 air that surrounds him. 



As one result of these experiments there 

 has been a great change in our ideas con- 

 cerning the physiological action of atmos- 

 pheric conditions. It had long been the 

 custom to ascribe to chemical components 

 of the atmosphere the bad effects of living 

 in air that had already been breathed by 

 human beings. The discovery of oxygen 

 and of carbon dioxide early in the last 

 century gave a great stimulus to this no- 

 tion, and it became firmly fixed in the minds 



of chemists, physiologists and physicians, 

 as well as the educated masses, that air that 

 had been breathed was vitiated chemically 

 and rendered unfit for human use by the 

 lack of oxygen, the accumulation of carbon 

 dioxide, and the presence of an organic 

 poison of unknown nature. No sooner had 

 this notion become widely accepted than 

 the laboratories began to demonstrate the 

 inadequacy of the supposed proof of the 

 notion, and — to cut a long story short — 

 we now know that, except under very un- 

 usual circumstances, the harmfulness of 

 respired air is not due to its chemical com- 

 ponents. By respiration oxygen can not 

 be reduced to a deleterious proportion nor 

 can carbon dioxide be produced in deleteri- 

 ous quantity, except under very unusual 

 conditions of living ; and the organic poison 

 of respiration has no real existence. The 

 harmfulness of living in confined air is 

 found in certain physical rather than chem- 

 ical features — the air is too warm, too 

 moist, and too still; and if it has not these 

 physical features it is not harmful. 



"We all have sat in crowded assemblies; 

 we all have experienced the hot, humid, 

 still days of an American summer. "We all 

 know the effects of such air on our sensa- 

 tions — the general bodily discomfort, the 

 sleepiness, the flushed face, the headache, 

 the disinclination to think or to act, the 

 general debility, the longing for relief. 

 But sensations are an inadequate measure 

 of bodily conditions. In what respects is 

 hot, humid, still air harmful? To answer 

 this question we must consult the records 

 of many researches, chiefly on human 

 beings, but partly on animals, that have 

 been undertaken since Hermans, 2 more than 

 thirty years ago, observed that in crowded 

 theaters and churches his own bodily tem- 

 perature rose. The most recent of these re- 

 searches is that of the New York State 



2 Hermans, Arch. f. Syg., I., 1, 1883. 



