1911] on Biology and the Cinematograph. 179 



well as a frog's heart recording its beats on a lilackened revolving 

 drum. 



Excised Heart of Tortoise Beating. Effect of Heat. 



The excised heart of a' dead tortoise, suspended and still living 

 and beating, exhibited the changes of form of the empty heart during 

 the contraction and relaxation of its several chambers ; while another 

 similar excised heart was shown beating on a glass plate. The effect 

 of heat on the heart-beat was clearly demonstrated. 



Effect of Chloroform on the Excised Heart of a Rahhit. 



Lastly, the excised heart of a dead rabbit, placed in connexion 

 with a perfusion apparatus supplied by Locke's fluid, so arranged as 

 to record its movements on a long strip of blackened paper moving 

 at a definite rate in front of the recording lever attached to the 

 heart, was shown. The same heart was then perfused with fluid 

 containing chloroform, and the audience could see how gradually but 

 steadily the heart ceased to beat, as if it were dead. But, no, on 

 washing out the chloroform with fresh Locke's fluid, the audience 

 could see how the apparently dead heart gradually resumed and 

 recorded its beats until its full vigour was estabHshed. The heart 

 was prepared and the apparatus arranged by Dr. Locke. 



\\\ contrast to the action of chloroform, the same heart was 

 shown subjected to the action of adrenalin, which threw the heart- 

 muscle into an extraordinary state of excitement, visible alike in the 

 heart itself and in the record on the smoked surface of the recording 

 apparatus. 



[W. S.J 



N 2 



