ELECTRICITY AND LIFE. 161 



mals down, and it is necessary to avoid rivers frequented 

 by the gymnotus, because, in attempting to ford them, 

 horses or mules might be killed by the discharges. To 

 capture these fish the Indians drive wild-horses into the 

 water, stirring the eels up out of the mud by their tram- 

 pling. The yellowish livid creatures press against the 

 horses under their bellies, throw down the greater part, and 

 kill some of them, but, exhausted in their turn, they are 

 then easily taken with the aid of small harpoons. The sav- 

 ages employ them to cure paralysis. Faraday compares 

 the shock of a gymnotus, which he had the opportunity to 

 study, to that of a strong battery of fifteen jars. A live 

 eel out of water, when touched by the hand, communicates 

 a shock strong in proportion to the extent of surface in 

 contact, and the stroke is felt up to the shoulder, and fol- 

 lowed by a very unpleasant numbness. It may be trans- 

 mitted through twenty persons in a chain, the first one 

 touching the back, and the last the belly of the eel. The 

 fishermen discover the presence of an eel in their nets by 

 experiencing a shock in throwing pailfuls of water on, to 

 wash them. Water is a good conductor, and this fish kills 

 or benumbs the animals it feeds on by delivering a dis- 

 charge through the water. 



Other sources of electricity are known to exist, besides 

 thunder-storms and fishes. Friction-machines, batteries, 

 and induction instruments, yield three kinds of currents 

 that act on vital functions, sometimes in a similar way, 

 but oftener with marked differences, which have only re- 

 cently been clearly distinguished. The action of static 

 electricity, and that of electricity of induction, more sudden 

 and violent, is particularly marked by mechanical effects so 

 striking that they have long distracted experimenters from 

 examining with due attention those effects of another sort, 

 produced by the galvanic current. Yet the latter in reali- 

 ty affects the animal tissues in a deeper way, and its re- 

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