NO. I AIR AND TUBERCULOSIS — HINSDALE ly 



were confined on the night of June, 1756, and only twenty-three 

 survived, he shows that numberless observations have all led to the 

 one conclusion that prolonged confinement in close air tends to lower 

 vitality and increase the incidence of certain infections, especially pul- 

 monary tuberculosis. However, it was found many years ago that 

 animals and men can tolerate without distress an increase of car- 

 bon dioxide in the air far beyond any concentration which it is likely 

 to acquire under the worst conditions of crowding, provided the 

 oxygen tension is maintained at a high level. Zuntz and Haldane 

 and his associates show that the normal excitement of the respiratory 

 nerve-center depends on the accumulation within it of carbon diox- 

 ide, a waste product, which it is a prime object of respiration to 

 remove. Sewall refers to Brown-Sequard and D'Arsonval's work 

 and, as bearing on it, the very recent work of Rosenau and Amoss.' 

 These workers condensed the vapor of human expiration and in- 

 jected the liquid into guinea-pigs. No symptoms followed this pro- 

 cedure. But after an appropriate interval of some weeks a little 

 of the blood-serum from the person supplying the moisture was 

 injected into the same animals. The outcome was an unmistakable 

 anaphylactic reaction. According to current beliefs the result showed 

 that the expired air must have contained proteid matter which sensi- 

 tized the pigs toward proteids in the blood of persons from whom 

 the first proteid was derived. The authors offer, as yet, no opinion 

 as to whether the proteid in the expired air possesses hygienic 

 significance. 



Prof. Sewall finds a suggestive analogy in the physiologic rela- 

 tions of carbon dioxide which it is one of the chief objects of 

 respiration to remove. Added to air in sufficient percentage it is 

 deadly to animals, yet so far from its being useless in the body, Hal- 

 dane and Priestley found that it must form four to five per cent of 

 the alveolar air for the maintenance of normal respiratory move- 

 ment, and a considerable lowering of its tension in the body would 

 be followed by speedy death. Boycott and Haldane note that the 

 subjective sense of invigoration and well-being excited by cold 

 weather is associated with a high tension of carbon dioxide in the 

 alveolar air.^ After summarizing the experiments of Heyman, Paul, 



' Organic Matter in the Expired Breath (Journal of Medical Research, 1911, 

 Vol. 25, 35). 



' Haldane and Priestley : The Regulation of the Lung Ventilation (Journal 

 of Physiology, 1905, Vol. 27, p. 225). 



Boycott and Haldane : The Effects of Low Atmospheric Pressure on Respi- 



