THE SANITATION OF AIR 21 



adapt itself to any condition tolerable at all in the long run. This is 

 true to an extent, as to the products of breathing as well as to tempera- 

 ture, but it is more than likely that any immunity from the habit of 

 living in badly used air is gained at the expense of vitality. 



Contaminated Air. — As distinguished from ' exhaustion ' of air, or 

 shortage of oxygen, with the corresponding increase of carbonic acid 

 and other waste products, the term ' contamination ' may be applied to 

 impurities of gaseous and solid nature, aside from the normally un- 

 avoidable. Tins includes, for instance, gases and vapor from industrial 

 sources, also smoke, soot and dust with its attendant bacteria. 



The amount of carbonic acid found in air is commonly regarded as 

 a measure of the degree of vitiation, but wherever pollution of the air 

 is likely to occur independent of an increase of combustion or respira- 

 tion that method of testing the purity naturally is deceptive. Indeed, 

 contamination quite often predominates exhaustion, and should always 

 be considered by itself, as a separate factor, according to the nature of 

 the case. While the effect of exhausted air may have been over- 

 estimated, the bearing of contamination on health does not seem to be 

 sufficiently realized. Its claims on vitality are of a different nature. 

 Any admixture of foreign gases may react directly upon the blood. 

 Such poisoning, however, is mostly due to local sources, readily de- 

 tected and prevented. By far the greater mischief is done by the 

 solid impurities afloat in the air. Although these are normally arrested 

 by the moist, mucous surfaces of nose and throat, they will, under 

 certain conditions, enter the lungs, fill the minute air chambers and 

 lodge there indefinitely. Through life in smoky or dusty surroundings 

 large portions of the lungs become useless in this manner, invite decay 

 and the fatal attacks of bacteria. Dr. Louis Ascher, in publishing the 

 results of his exhaustive investigations on the subject, has shown con- 

 clusively that smoky atmosphere encourages diseases of the respiratory 

 organs, materially shortens the life of consumptives and bears dis- 

 tinctly on the mortality of afflicted districts. The charts of distribu- 

 tion of pulmonary tuberculosis in Chicago show indeed the cases to be 

 most frequent near the cluster of railway stations. The appalling con- 

 tingent of lung patients sent to the Eocky Mountains from our smoky 

 cities of the middle west gives a sad testimony to these facts. 



Still greater mischief is done by solid impurities, especially dust, 

 as the carriers of disease germs. True, the best authorities now agree 

 that the presence of microbes in the respiratory organs does not neces- 

 sarily produce disease, and that the germs must first make their way 

 into the system in order to develop, and find it in poor condition before 

 they can do serious harm. Predisposition, in the form of inflammation 

 combined with lowered vitality, seems therefore necessary to develop the 

 more serious pulmonary diseases. Unfortunately these predisposing 



vol. lxxx. — 2. 



