HIGHER LIFE IN WATERS. 



99 



number of nervous filaments. This apparatus is some- 

 thing like the galvanic pile. John Hunter counted twelve 

 hundred columns in a very large fish, and about one hun- 

 dred and fifty plates to the inch. In one specimen, Pro- 

 fessor Wyman estimated the number of plates in an Ameri- 

 can torpedo, a species which sometimes reaches a length 

 of four and one half feet, and a width of three feet, at the 

 enormous number of three hundred thousand, the prisms 

 being about two inches in height and containing one hun- 

 dred plates to the inch. The intervals between the plates 



The Torpedo. 



were filled with an albuminous fluid, mostly water, but 

 containing salt in solution. 



5. In the torpedo the shock is most powerful when con- 

 nection is made between the back and the abdomen. Act- 

 ual contact with the fish, however, is not necessary, as it 

 is well known by the Neapolitan fishermen that the shock 

 is felt when the water is dashed on it, the electric current 

 passing up along the stream, the circuit being completed 

 through the earth to the stomach of the fish. The tor- 

 pedo never uses its power for aggressive uses, as it is ratber 

 a timid fish ; but it makes itself dreaded by other fish, 

 which soon learn to let this living electric battery alone- 



