374 



ELECTRO-PHYSIOLOGY 



CHAP. 



seen from the surface) first described in detail by Boll for 

 Torpedo. The nerve-ending itself presents, according to Sachs, 

 a varying aspect "resembling now Kiihne's end-plate, and now 

 Schultze's net." According to Fritsch, the thorn-like papillae are 

 to be viewed as the real bearers of the nerve -endings in the 



Gymnotus plates. " Upon these 

 there are comparatively coarse 

 prolongations of the axis-cylinder," 

 so that they are "allied to the 

 stalk of the Malapterurus plate." 

 As regards the indisputable genetic 

 relation between the electrical 

 organs and striated muscle, it may 

 be conjectured that the mode of 

 ending of the nerve in the sub- 

 stance of the plate is analogous 

 to that of Torpedo, although the 

 observations made up to this time 

 afford no positive evidence of it. 

 The plates in the wide compart- 

 ments of Sachs' columns are dis- 

 tinguished from the others mainly 



FIG. 243. One wide and two narrow compart- by the greater length of the 

 ments of Gymnotus, seen in cross-section .-i-i /T7 ,. o A Ox 



(as in Fig. 241) under a high power, with an tenor papillse (.big. 24:6), in 

 enclosed plates (p). (DU Bois-Reymond.) which, moreover, in the fresh state, 

 Sachs observed a broad, dim cross-striation and traces of double 

 refraction, in the axis or at the margin. 



If the final distribution of the nerve in the peripheral organ 

 (electrical plates) is thus uncertain, no such doubt exists as to 

 the central origin and coarser anatomical structure of the electrical 

 nerves. 



Valentin, reasoning from a likeness (afterwards proved to be 

 inadequate) between the brain of Gymnotus and that of the eel, 

 assumed a certain section of it (by analogy with Torpedo) to 

 be the electrical lobe, and centre whence spring the electrical 

 nerves. Later investigations, however, showed the part of the 

 brain in question to be identical with the cerebellum so markedly 

 developed in the allied cat-fish (Silurus glanis), the spinal cord 

 being the immediate seat of origin for the electrical nerves. Max 

 Schultze first pointed out the very numerous and large ganglion- 



