ON LIVING MALAPTERURUS. 389 



and finally send l numerous ramifications backwards into the surfaces 

 originally turned away from their direction of distribution. Max 

 Schultze (then in Halle) recognised in Bilharz' drawings of the 

 electrical plates of the Malapterurus, traces of a similar arrangement, 

 and the thought struck him, that this might be the explanation of 

 the discrepancy between Bilharz' result and that observed by me. 

 After I had sent to Schultze pieces of the organ of the Malapterurus 

 some as fresh as possible, some preserved in suitable liquids he 

 succeeded, as he believed, in confirming with certainty his previous 

 conjecture. 



According to him, the nerve-tubes enter the posterior positive 

 surface of the electrical plates indeed, but do not sink into them. 

 They go through a hole in the middle of the plate to its anterior 

 negative side, and there spread out backwards in the shape of 

 a bell. The edge of the bell, as corresponding with the true nerve- 

 ending, blends with the negative surface of the plate at the 

 circumference of the hole 2 . Thus Pacini's rule might still hold 

 good, according to which, that surface of an electrical plate into 

 which the nerves bury themselves is always negative at the 

 moment of the shock ; but in the case of Malapterurus and of 

 those species of Mormyrus, in virtue of the peculiar arrangement 

 described, the surface which, according to this rule, ought to be 

 negative, becomes positive, and conversely. 



Schultze's successors reject this explanation. The character of 

 the membrane scarcely admits of its being considered as an expan- 

 sion of the nerve, itself flat, which spreads into it, and it must 

 be admitted that it is as often seen to continue into the plate in 

 a transverse plane, as to originate in the form of a bell 3 with its 

 edge to the anterior circumference of the hole. 



Another reason, hitherto disregarded, in opposition to Pacini's rule, 

 has its weight. Robin succeeded apparently, where Joh. Miiller and 

 Matteucci failed, in eliciting a shock from the pseudo-electrical organ 

 of the common skate 4 . In this organ the nerves terminate at the 



1 Unlersuchungen zur Ichthyologie, etc. Freiburg, vol. i. 1857, 4. p. 29. 



2 Zur Kenntniss der elektrischen Organe, etc., loc. cit. pp. 14, 15. 



3 Comp. K. Hartmann in the Archiv fur Anatomie, etc., 1861, p. 661. F. Boll in 

 Schultze's Archiv fur mikroscopische Anatomie, 1873, vol. x. p. 242. Babuchin in 

 Centralblatt fur die medicinischen Wissenschaften, 1875, pp. 131, 132. 



4 See my Berichte in den Fortschritten der Physik im Jahre, 1846, etc. 

 II. Jahrgang. Berlin, 1848, p. 469; in the year 1847, III. Jahrgang. 1850, p. 440; 

 comp. Untersuchungen, etc., vol. ii. part i. p. 207 ; Peters never obtained a shock 

 from the Mormyri. The natives were also unaware of any striking property of 

 these fish. But he only came across emaciated fish, the electrical organs of which 



