156 PHYSIOLOGY OF MUSCLES AJsD NERVES. 



by various observers, and the electric character of their 

 innate force was incontrovertibly shown. Faraday's 

 study of the electric eel, and du Bois-Eeymond's of 

 another electric fish, are especially important. 



There are three fishes, especially, wdiich have been 

 proved to possessthis capacity for giving electric shocks. 

 These are, the electric ray of the Adriatic and Medi- 

 terranean {Torpedo electrica and T. marmorata) ; the 

 electric eel (Gymnotus electricus), which occurs in the 

 fresh waters of South America ; and lastly, another elec- 

 tric fish (^Malapterurus electricus or M. benioiensis), 

 which has but recently been carefully studied, and 

 which occurs in the rivers of the Bay of Benin on the 

 east coast of Africa. We cannot omit this opportunity 

 of inserting Alexander von Humboldt's description of 

 the electric eel and its action ' : — • 



' The crocodile and the jaguar are not, however, the 

 only enemies that threaten the South American horse ; 

 for even among the fishes it has a dangerous foe." The 

 marshy waters of Bera and Eastro are filled with innu- 

 merable electric eels, which at pleasure are able to 

 discharge a deadening shock from every part of their 

 slimy, yellow-speckled bodies. This species of gymnotus 

 is about five or six feet in length. It is powerful enough 

 to kill the largest animals when it discharges its ner- 

 vous organs at one shock in a favourable direction. It 

 was once found necessary to change the line of road 

 from Uritucu across the savannah owing to the number 

 of horses which, in fording a certain rivulet, annually 

 fell a sacrifice to these electric eels, which had accu- 

 mulated there in great numbers. All other species of 

 fish shim the vicinity of these formidable creatures. 



' Vietvs of Nattire. 



