58 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 60 





The pulse frequency was diminished in each case by putting on 

 the fans and the discomfort relieved. No headache followed the 

 experiment. 



After making these preliminary experiments two of us (R. A. 

 Rowlands and H. B. Walker) carried out a series of observations, 

 each acting as subject in turn. 



The subject breathed through a Zuntz meter fitted with a mouth- 

 piece, an inlet and an outlet valve. A soda-lime tin, to absorb C0 2 , 

 was at times interposed between the inlet and the mouth. The effect 

 on the respiratory ventilation and on the pulse rate was recorded both 

 when resting and when working. The work consisted in pulling up 

 a 20-kilogram weight about I meter high by means of a pulley and 

 rope. 



In many of the experiments C0 2 was put into the chamber from 

 a bag full of the gas. The subjects inside could not tell when the 

 gas was introduced, not even if the percentage was suddenly raised 

 to 2. 



The introduction of this amount of the gas made no sensible 

 difference to them. The subjects wore only a vest, pants and shoes 

 in most of these experiments. When they wore their ordinary 

 clothing the effect on the frequency of the pulse was more marked 

 and the discomfort from heat and moisture much greater. 



In every one of the experiments the putting on of the fans gave 

 great relief. The refreshing effect of the moving air acting on the 

 skin is very great, but this cannot be measured and recorded in 

 figures. 



