lU ESSAYS AND OBSERVATIONS 



quater before twelve. At two o'clock 

 afternoon, the auricle, which, having ex- 

 pelled all its blood, was now only filled with 

 air, continued its motions j but the heart lay 

 at reft. Ten minutes paft four, V. e. fhe 

 hours and forty four minutes after the frog 

 was taken out of the folution, the auricle 

 of its heart beat 9 times in fixty four fe- 

 conds. 



8. I laid bare the abdominal mufcles and 

 thorax of another frog, and at fourteen mi- 

 nutes paft eight in the morning, immerfed 

 it as above in a turbid folution of opium. 

 Fourteen minutes paft nine, I took it out of 

 the folution, and laid open its thorax and 

 pericardium ; after which the heart began to 

 beat at the rate of nine times in a minute : 

 but the auricle, which was greatly diftended 

 with blood, made no motion, except in fo 

 far as it was agitated a little by the pulfation 

 of the heart : nor were the mufcles of the 

 legs or thighs brought into contradlion by 

 cutting or tearing their fibres. At half an 

 hour paft nine the heart beat only 7 times 

 in a minute j and the auricle, which was 

 now pretty empty of blood, and, in place 

 of it, filled with air, had a pulfation as well 



as 



i 



