ELECTRIC POWER OF GYMNOTUS. 205 



than an apparatus for accumulating that power, as 

 electricity is accumulated in Leyden jars. The 

 power exists only during life, and while the brain 

 is active ; and is voluntary and dependent on the 

 integrity [perfect conductibility] of the nerves. 

 Direct irritation of the brain will effect a shock." 



Humboldt narrates a conflict he saw in South 

 America between electric eels and horses driven 

 into the water among them, purposely to exhaust 

 their muscular power. " Gradually the impetuosity 

 of the unequal conflict diminished, arid the ex- 

 hausted eels dispersed." He adds, "they require 

 long repose and abundance of food to repair the 

 loss of galvanic force expended." This illustrates 

 admirably the parallel between fatigue and en- 

 feebled power of developing electric action. 



In the waning power of muscular action result- 

 ing from continuous labors of the day, and in the 

 nightly restoration of this power, accumulated 

 during the repose of the muscles, we have the ren- 

 ovation of the exhausted electric excitation that 

 develops vitality. 



Some of the lower classes of aquatic animals 

 appear capable of exciting electrical luminosity in 

 a greater or less degree, producing the phospho- 

 rescence of the sea, seen most remarkably between 

 the tropics. The excitation from .the wheels of an 

 ocean steamer causes a wake so brilliant that it 

 lights up the darkness. 



A less intense light is sometimes produced in 



