130 HEAT CHAP. X. §• HI. 



Sect. III. On the Manifestation of Heat during 

 Muscular Contrarian. 



Becqdebel and Bbeschet', in their ingenious 

 experiments upon the relative temperature of the 

 different tissues in the living animsd, also found 

 that, during muscular contraction, the temperature 

 of the muscular tissue was increased. The amoiuit of 

 deflection was equivalent to about 1° of Fahrenheit. 



Matteucci'' took two flasks, in each of which he 

 suspended the limbs of five frogs, and in the middle 

 of these limbs a delicate thermometer. Having waited 

 until the temperature of the limbs had become 

 stationary, he then caused the muscles in one of the 

 flasks to contract violently. In the first experiment, 

 the temperature of the air was + 12°60, the ther- 

 mometer in the middle of the frogs indicated -}- 1 3°10 ; 

 upon making the muscles contract for five or six 

 minutes, the latter indicated + 13°50. At this point 

 it continued stationary during eight or ten minutes. 

 In another experiment, the temperature of the air 

 was + 12°80, in the middle of the frogs + 13°50, 

 during the contractions it ascended to -|- 13°95. 

 An hour afterwards, the temperatm-e being lowered 

 to -\- ] 3°40, he then excited tlie muscles to contract, 

 which they did although feebly, and the temperature 

 only indicated -\- 13°60. In a thu'd experiment, the 

 temperature of the air being -|- 12°70, in the middle 



» Beoquerel, torn. iv. p. 21. 



' Annales de Chimie et de Physique, Juin, 1856. 



