Movements of the Heart of the Coppcr-liend Snake. 29 



and finally the snake was removed from tlie vessel with its 

 month now gaping. The heart was first observed with the 

 pericardium intact, and had an average of 39 beats per 

 miiuite for the first 3 minutes. The pericardium was next 

 slit u|), and the heart exposed, and the average for 3 minutes 

 was 23 beats per minute. The heart was now excised, 

 14 minutes after the i-emoval of the snake from the 

 cidoroform. At first it beat very sh)wly, only about 8 |)er 

 minute, then it increased after 20 minutes to an average of 

 31 beats per minute, and at the end of an hour it was 

 beating at tlie average rate of 33 per minute. Throughout 

 this period the beating was regular, that of the ventricle and 

 two auricles alternating in regular succession. 



When ob.served two hours after excision, the rate of beat 

 of ventricle and auricles was very disproportionate. While 

 the auricles beat in unison at an average rate of 27 per 

 minute, the ventricle only averaged 9 beats per minute, or 

 one-third that of auricles. Three hours after excision, the 

 auricles averaged 22 beats per minute, and the ventricles 

 only G, or for 3 minutes in succession, 5, 6, and 7 beats 

 respectively. Shortly afterwards the ventricle ceased to 

 beat, a little over 8 hours after excision. In this instance 

 there was no response to stimulation, at least 30 ininutes 

 after cessation of spontaneous beating. 



The times of the jirincipal events may now be given. 

 Chloroform was administered at 1J.27 a.m., snake taken out 

 at 11.42 a.m., heart excised at 11.56 a.m., ventricle was seen 

 beating feebly but fairly regular at 3 o'clock, p.m. ; observed 

 20 minutes afterwards, and there was no sign of beating, 

 even after watching for some time, so that the excised 

 heart in this instance beat for at least 3 hours 4 minutes. 

 Both auricles continued beating in unison, and 4 hours after 

 excision the average number of beats per minute was 28, 

 the left, however, feeble as compared with the right auricle. 

 Five hours after excision, the average in both was 24 per 

 minute; and 6 hours after excision, the average was 18 per 

 minute, that of the left being now exceedingly feeble. 

 Bu.siness here called me away, so that the final beating was 

 not observed, but probably the left auricle ceased first, as in 

 the preceding case. The temperature here varied from 

 18° to 23° C, slowly and steadily increasing from the former 

 to the latter towards the end of the observation. 



A third copper-head snake was obtained on the 1 4th May 

 at Oakleigh. It was a very young one, only measuring 



