SYMPOSIUM ON SANITATION 63 



Taking- now the more limited view of housing, i. e., the 

 house and its mechanical equipment, we find that there is 

 much difference of opinion as to the steps to be taken to se- 

 cure healthful housing. The reason is that sanitary science is 

 undergoing radical and most interesting changes, owing to 

 the development of the sciences on which it largely depends, 

 viz.. bacteriology and physiology. Many opinions and prac- 

 tices based on outgrown theories are still deeply rooted and 

 find expression in views concerning housing. 



In the interest of efHciency and progress, it behooves 

 those who work for the well-being of social groups to take 

 measures to correct popular misapprehensions and urge the 

 development of engineering and building methods which shall 

 conform to our new knowledge, ^^"e need, moreover, not to- 

 cumber further our statutes and ordinances with measures 

 which are not only incapable of enforcement but futile and 

 costly if put in practice. In illustration, some of these new 

 views may be enumerated and some conclusions drawn from 

 them, although within the limits of this paper hardly more 

 than a sketch is possible. 



In the first place , 



(a) The quantity of carbon dioxide is not a measure 

 of unhealthfulness of air. 



(b) Ordinary variations in the normal gaseous consti- 

 tuents of air produce no apparent ill effects on people. 



(f) The discomfort ordinarily attributed to so-called 

 "bad-air" is due to high humidity combined Avith high tem- 

 perature and these conditions derange the health. 



Long after the toxicity of carbon dioxide had been dis- 

 proved, its presence in air was taken as a measure of the 

 defilement of air in other ways, but it is manifestly absurd to 

 assume any constant relation between carbon dioxide and 

 carbon monoxide, which is the only really harmful gas which 

 is likely to be found in houses, or between carbon 

 dioxide and pathogenic organisms, which may be in 

 the air of houses occupied by diseased persons. It 

 is clear, therefore, that any attempt to keep the carbon di- 

 oxide down to a fixed limit by renewal of the air supply or 

 in any other w^ay may be ineflfective in securing healthful 

 conditions. Consequently, laws requiring the supply of a 

 given amount of air per person or a given cubic space 

 per person fall wide of the mark. The real aim should be 

 toward securing movement of air, since thereby the warm 

 moist blanket of air which gradually accumulates about the 

 bodies of people in inhabited rooms may be removed. In 

 other words, it has been adequately proved that people do not 

 need a large supply of air providing what they have is kept 



