412 



ELECTRO-PHYSIOLOGY 



CHAP. 



Schonlein found that the discharges were sufficiently vigorous to 

 fill the entire basin, measuring 1 x 0'4 x 0'3, with lines of 

 current audible in the telephone. He thus detected that the 

 animals sometimes give spontaneous discharges without apparently 

 any direct stimulus, e.g. on the approach of other animals, or of the 

 collecting plate. But as a rule a true discharge follows only from 



FIG. 268. Schema for leading off the shock of Torpedo.] FW= frog -alarum. (Du Bois-Reymond.) 



contact, or some other excitation. In Gymnotus, and according 

 to du Bois-Keymond in Malapterurus also, the seat of stimulation 

 is by no means immaterial. The barbels of the last fish seem 

 to be peculiarly insensitive, since their stimulation never pro- 

 duces a discharge. As regards requisite strength of stimulus, 

 again, great differences are apparent. Gkjmnotus at times reacts 

 to the faintest impression, at others a discharge can only be 

 provoked by determined " picking " with a pointed body. In 



