370 OBSERVATIONS AND EXPERIMENTS 



fishes, one of them had remained as good as unknown to ns. 

 The electrical ray of European coasts 1 had been many times in- 

 vestigated since the revival of science in the seventeenth century, 

 in all its relations, and each time with more perfect resources. 

 The electrical eel had been investigated in its own home by 

 Alexander von Humboldt, and this fish had already been brought 

 often to Europe, and had been observed by the first experimenter 

 of all times, by Faraday himself. On the other hand, the elec- 

 trical sheath fish, or Malapterurus electricug 2 , which inhabits the 

 rivers of Africa, which was known to the ancients, and which is 

 still no rare appearance in Bulak, the fish-market of Cairo, and 

 which thus, next to the electrical ray, seemed the most accessible to 

 science, was notwithstanding very little known. Until the year 

 1857 we possessed only isolated anatomical details which left even 

 the coarse anatomy of its organ unexplained. As to its electrical 

 action, there existed indeed already a valuable experiment on it, as 

 will be shown hereafter, but this was so concealed in literature, that 

 it might escape even the most earnest student of the subject. 

 (See note to p. 388.) 



A fortunate chain of circumstances has in so far supplied this 

 want, that now the Malapterurus ranks with the Torpedo as one of 

 the two electrical fishes of which the anatomy is best known ; and 

 that not only the most pressing physiological questions relating to 

 it are answered, bull light has been thrown on entirely new aspects 

 of the phenomenon. 



Theodor Bilharz, professor of anatomy in the medical school in 

 Cairo, who has since unfortunately been snatched away from science 

 by death, published in 1857 an anatomical description of the 

 Malapterurus, worked out with the aid of modern appliances 3 . In this 

 investigation he first obtained an insight into the structure of an 

 electrical organ. Setting aside the parts intended for support and 

 nourishment, such an organ, according to Bilharz, is to be re- 

 garded as a direct continuation of the nervous system. In an 

 electrical organ a great number of small plates are arranged above 



1 For the sake of brevity, I speak of the family of the Torpediniae, so rich in 

 genera and species, and which was increased by Linnaes' species Raja Torpedo, by 

 the name of one of the three electrical fishes, i. e. Torpedo. 



2 Herr W. Peters has brought into use the name Malopterurus, which is at least 

 somewhat more correct than the name framed by Lacepede, Malapterurus (instead 

 of Malakopterwrus). [Considering that Malapterurus is familiar to zoological stu- 

 dents, it has been thought best to adopt that mode of spelling. Ed.] 



3 Das elektrische Organ des Zitterwelses anatomisch beschrieben, etc. Leipzig, 

 1857, Fol. 



