NOTE EEGAEDING THE EFFECT OF ELEC- 

 TRICAL STIMULATION OF THE FEOG'S 

 HEAET, ETC. 



This research was the outcome of the observations made by 

 Eomanes in 187G and 1877 upon Medusse. He found in these 

 animals tliat the rhythmical movements of the bell are kept up 

 by a ring of ganglia round its margin. When a strip of con- 

 tractile tissue containing the ganglia is cut away from the bell 

 for a certain distance but left attached at one end, stimuli can 

 pass along the strip in two ways, either as contraction in the 

 contractile tissue of the strip or along the nerves. The nervous 



Fig. 164. 



conduction may either pass along in front of the contraction 

 when this is present, or may pass along without any contraction 

 at all occurring in the strip, and only become manifest by 

 movements in the tentacles which fringe the strip and are more 

 sensitive than the strip itself. 



It was in order to find out whether the cardiac contraction 



