NO. I AIR AND TUBERCULOSIS — HINSDALE IQ 



the London health authorities insist that in factories the percentage 

 of carbon dioxide must not rise above the usual amount allowed, 

 say ten parts in ten thousand, he remarks that the regulations do not 

 prescribe any limitations of the wet-bulb temperature adding that 

 while carbon dioxide does not do any harm whatever a wet-bulb 

 temperature of 75° F. is very bad and ought not to be tolerated in 

 any factory. All the current teaching of the hygiene of ventilation 

 runs on the subject of chemical purity of the air; but according 

 to Prof. Hill the essential thing in ventilation is heat, not chemical 

 purity. It does not matter if there is i per cent more carbon dioxide 

 and I per cent less of oxygen. In the worst ventilated rooms there 

 is not I per cent less oxygen. The only effect of an excess of car- 

 bon dioxide is to make one breathe a little more deeply. A much 

 higher amount has to be attained to have any toxic effect. As to 

 organic impurities derived from respiration there is no physiologic 

 evidence of their toxicity or that they are of any importance ex- 

 cept as an indicator of the number of bacteria in air. The way to 

 keep air best from the physiologic point of view is shown by the 

 following experiment performed by Hill at the London Hospital: 

 Into a small chamber which holds about three cubic meters he put 

 eight students and sealed them up air tight. They entered joking 

 and lively and at the end of 44 minutes the wet bulb temperature 

 had risen to 83° F. They had ceased to laugh and joke and the dry 

 bulb stood at 87° F. They were wet with sweat and their faces 

 were congested. The carbon dioxide had risen to 5.26 per cent and 

 the oxygen had fallen to 15.1 per cent. Hill then put on three elec- 

 tric fans and merely whirled the air about just as it was. The 

 effect was like magic ; the students at once felt perfectly comfortable, 

 but as soon as the fans stopped they felt as bad as ever and they 

 cried out for the fans. These and other experiments related, accord- 

 ing to Hill, show that all the discomfort from breathing air in a con- 

 fined space is due to heat and moisture and not to carbon dioxide. 

 Even after five repetitions of the experiment there were no after- 

 eft'ects, such as headache. The obvious inference is that the air 

 must be kept in motion to avoid bad effects. The open air treat- 

 ment of disease is not altogether a matter of fresh air, but the 

 constant cooling of the body by the circulation of air which makes 

 us eat more and promotes activity. This leads to the general 

 strengthening of the body because the blood is not only circulated 

 by the heart but by every muscle in the body. 



There cannot be efficient circulation without constant movement 



