284 ESSAYS AKD OBSERVATIONS 



auricle was not near fo much diftended with 

 blood, nor the heart fo niuch fwelled as in 

 thofe frogs which had a folution of opium 

 injeded into their flomach and guts *. At 

 one o'clock {viz, an hour and fifty one mi- 

 nutes after decollation), the heart of this 

 frog made 20 piilfations in a minute. At half 

 an hour paft two, when the room was be- 

 come warmer by the fhining of the fun, it 

 beat 25 times in a minute ^ and when placed 

 IB the fun beams, it performed 31 contra- 

 ctions in that time. After this, I removed 

 the frog to an eaft window, where it was 

 expofed to a cool breeze \ upon which the 

 motion of its heart became flower, fo that 

 in a fhort time it only made 25 pulfes in a 

 minute. I then expofed it anew to the fun- 

 beams, by which its motion was foon 

 quickened, fo that it beat 30 times in a 

 minute. 



At twenty five minutes paft five in the 

 evening, [viz. Jix hours and fixteen minutes 

 after decollation and the deftrudtion of its 

 fpinal marrcvv) the auricle of this frog's heart, 

 which was ftill filled with blood, contrad:- 



ed 



■* Spe No. 3. above, and Eflay on the Vital and other 

 Involuntary Morions of Animals, p. 371 & 372. 



