LECTURE I. 25 



frog severed from the body, by voltaic 

 electricity, the muscular actions are at first 

 vivid and forcible, but they grow fainter 

 and feebler on repeated excitement. Yet 

 if we wait a little till they seem to regain 

 their power, they become vivid and forci- 

 ble as at first from the same degree of ex- 

 citement. Such actions may be excited at 

 intervals for twenty-four hours, though with 

 a gradual diminution in their power, after 

 which, in general, they can be no longer 

 excited, and then the muscles become per- 

 manently and rigidly contracted. The 

 foregoing facts appear to me to show the 

 impropriety of the phrase, exhausted irri- 

 tability, which is in common use to express 

 our inability by the eifort of our will to 

 continue the actions of our voluntary mus- 

 cles : it seems manifest that the irritability 

 is not exhausted but fatigued. 



The rigid contraction of the muscles 

 after death, is the effect of irritability : it is 

 its last act. A considerable force is re- 

 quired to overcome this contraction, or to 

 bend the rigid limbs of the dead body. 



