NO. 23 INFLUENCE OF ATMOSPHERE ON HEALTH \~ 



oxygen by 1 per cent at sea-level has not the slightest effect on 

 health and comfort, and that none of the effects of ill-ventilated 

 rooms can be ascribed to want of oxygen. 



By breathing over 70 per cent of oxygen the frequency of the 

 heart is diminished four or five beats per minute in the normal rest- 

 ing individual. (J. Parkinson, Journ. Physiol., 1912; also Benedict 

 and Higgins, Amer. Journ. Physiol., Vol. 28, 191 1.) In cases of pneu- 

 monia with failing heart, the regularity, strength and fulness of the 

 pulse are notably restored by oxygen-inhalation. G. N. Stewart has 

 found that the rate of blood-flow in the arm of one particular cyanosed 

 patient was increased four or five times by oxygen-inhalation — not so 

 in the other cases tested or in the resting, normal man. Cases of 

 pneumonia and heart disease are sent down to the sea-level from 

 high altitudes such as Mexico City, for this is recognized as giving 

 the best chance of recovery. Chloroform, too, is a more dangerous 

 anaesthetic at high altitudes (Johannesburg) and is made safe when 

 given with oxygen. 



THE CARBON DIOXIDE 



Owing to the fact that the percentage of C0 2 is the usual test of 

 ventilation and that only a very few parts per 10,000 in excess of 

 fresh air are permitted by the English Factory Acts, it is gener- 

 ally supposed that C0 2 is a poison and that any considerable excess 

 has a deleterious effect on the human body. Xo supposition could 

 be further from the truth. 



Reiset ' gave the percentage of O > 2 as 0.0294 four miles from 

 Dieppe, 0.02898 in a trefoil field, 0.03178 near a flock of sheep. In 

 London a summer average is o.037<j, and a winter average 0.0422. 

 In fog it was 0.072 and once as high as o. 141. In a Court of Chan- 

 cery, 0.20; in a workshop. 0.30; in the pit of a theater, 0.32; in a 

 crowded meeting, 0.365; in badly ventilated barracks. 0.1242 to 

 0.195 ! m tne general hospital, Madrid, 0.32 to 0.43 ; in a girls' school 

 (70 girls and 10,400 cubic feet). 0.73. We see, then, that the per- 

 centage of CO a in the worst-ventilated room assuredly does not rise 

 above 0.5 per cent or, at the outside. 1 per cent. It is impossible 

 that any excess of CO z should enter into our bodies when we breathe 

 such air, for whatever the percentage of C0 2 in the atmosphere may 

 be, that in the pulmonary air is kept constant at about 5 per cent of 

 an atmosphere by the action of the respiratory center. It is the con- 



1 Cited after Russell. Vide supra. 



