NO. 23 INFLUENCE OF ATMOSPHERE ON HEALTH 8l 



be entirely removed by moving and cooling the air. When work is 

 done without over-fatigue, the frequency of the pulse, which is 

 accelerated by work, quickly returns to normal. Our results show 

 that increased percentages of C0 2 and diminished oxygen per- 

 centages of 2 to 3 per cent, and even 4 to 5 per cent, have little 

 effect in modifying the frequency of the pulse, while the temperature 

 and humidity of the air have a profound effect. The feelings of dis- 

 comfort depend on the excessive heat and humidity, and are relieved 

 by cooling and whirling the air in the chamber. If we suddenly 

 raised the percentage of C0 2 in the chamber up to 2 per cent, we 

 found the subjects inside were quite unaware of this. If we sat 

 outside and breathed the air in the chamber through a tube, we felt 

 none of the discomfort which was being experienced by those shut 

 up inside. Similarly, if one of those in the chamber breathed the 

 pure air outside through a tube, he was not relieved. 



The pulmonary ventilation mainly depends on the percentage of 

 CO L , but may also be used as part of the heat-regulating mechanism. 



The observations made by Pembrey and Collis ' on the weaving 

 mill operatives at Darwen show that the skin of the face may be 

 4° to 13 F. higher in the mill when the wet bulb is 71 ° F. than at 

 home when the wet-bulb temperature is about 55 ° F. The tendency 

 of the warm, humid atmosphere of the mill is to establish a more 

 uniform temperature of the body as a whole (surface and deep 

 temperatures) and to throw a tax upon the power of accommoda- 

 tion, as indicated by the rapid pulse and low blood-pressure. 



The mill workers are w r et with the steam blown into the sheds, 

 their clothes and bodies are moist, and the long hours of exposure 

 to such uncomfortable conditions are most deleterious to physical 

 vigor and happiness. The operatives asked that they might be 

 allowed to work without steam-injectors and with diminished venti- 

 lation, so that the mill rooms became saturated with moisture 

 evaporated from the bodies of the operatives. The old regulations, 

 while forbidding more than 6 parts in 10,000 C( ) 2 , put no limit to 

 the wet-bulb temperature, and this often became excessive on hot 

 summer days. The operatives were quite right ; less ventilation and 

 a lower wet bulb is far better than ample ventilation and a high wet 

 bulb. The permissible limit of CO a has now been raised to 11 parts 

 in 10,000 and the wet-bulb temperature has been controlled within 

 reasonable limits. (Home Office Departmental Committee Reports 

 on Humidity and Ventilation in Cotton Weaving Sheds, 191 1 . ) 



1 Proc. Physiol. Soc. Oct. 21. tqti; Journ. Physiol., Vol. 43. 

 6 



