Action of Temperature and Humidity. ii 



group of animals the temperature averaged approximately 21° C. 

 and the humidity approximately 54 per cent.; with the other a 

 temperature of 33 0 C. and a humidity of 89 per cent, were em- 

 ployed; that is, the animals of the first group were kept under 

 comfortable atmospheric conditions, those of the second group 

 were given air approximating that of a hot, humid summer day. 

 In some of the animals the rectal temperature was observed at 

 the beginning and the end of the period of confinement. At the 

 end of this period the cats were taken from the chamber and 

 killed by instantaneous decapitation. The blood was collected 

 for the estimation of sugar, and certain of the muscles were 

 removed and stimulated until they were exhausted, each con- 

 traction being recorded graphically and the total duration of the 

 working period and the total amount of work performed being 

 determined. The average results of the observations on the 

 muscles are presented herewith. 





Tempera- 

 ture in 

 Degrees C. 



Humidity 

 in Per Cent. 



Duration of 

 Work in 

 Minutes. 



Work Done 

 in Gm. Mm. 



Percentage 

 of Work 

 Done. 



Sternal strip of diaphragm . . . 



21-3 



SS 



196 



157.66s 



100 





33 



89 



212 



136.123 



86 



Extensor longus digitorum . . . 



21 



59 



101 



3L305 



100 





32.6 



89 



80 



25.714 



82 





21.7 



49 



138 



46,598 



100 





33 



89 



109 



29.785 



63-9 



Under the influence of the high temperature and the high humidity, 

 therefore, the total amount of work which the muscles are capable 

 of doing before exhaustion sets in is markedly diminished; and 

 the total period of working power is shortened, except in the case 

 of the diaphragm. 



The observations show that the bodily temperature of the 

 animals rises in the atmosphere of high temperature and high 

 humidity. This is seen from the following average temperatures. 



Temperature of Air 



Humidity of Air in 



Bodily Temperature 



Bodily Temperature 



in Degrees C. 



Per Cent. 



before Confinement. 



after Confinement. 



21.4 



50 



39-13 



39-03 



33-1 



89 



39-33 



39-81 



