758 REPORT— 1892. 



belonging to the cutaneous system, most likely transformed gland-cells of tlie skin, 

 which are found in Malopterurus. 



In the nervous apparatus, to make these organs act according to the impulse 

 given by the will of the fish, there are found in every instance wonderfully developed 

 ganglion-cells, from which the impulse passes directly to the electrical organs. In 

 all the cases where the electrical organs are of a true muscuhxr character the 

 ganglion-cells send out well-defined, not branched, axis cylinders, one from each 

 cell, which may easily be traced into the anterior roots of the spinal cord or 

 medidla oblongata. These cells are more or less plentiful just as the nerve fibres 

 arising from them are. 



In the cutaneous organs of Malopterurus there are only two ganglion-cells for 

 innervation, one on each side, and only one nerve fibre belonging to each cell. 

 That fibre does not rise from the cell-protoplasm as a true axis cylinder, but is 

 formed by a combination of protoplas'mic processes at a certain distance from the 

 giant ganglion-cell. The electric current in the latter case has the opposite direc- 

 tion from that in the former. 



It should also be kept in mind that in many other cases, not concerned with 

 the electric fishes, peculiar ganglion-cells are found where peculiar functions of the 

 nervous system occur. For instance, large ganglion-cells are found in the motor 

 region of tlie brain, first seen by Betz, who looked for them on purpose to state 

 anatomically the laws of localisation i'ound by I'rofessor Ilitzig and myself — a 

 branch of science which has been followed up iu a glorious way by Professor 

 Horsley, of London. 



Inflammation and decav' of motor ganglion-cells might cause spasms in the 

 muscles belonging to them, as was stated lately by Professor Ilitzig in a case of 

 tetanus of the head, where the motor cells of the fifth nerve were found to exhibit 

 marked vacuolation. 



All these facts prove evidently that the ganglion-cells must be essential for 

 .sending on the nerve impulse to peripheral organs, and that the view recently put 

 forward by Nansen, that the ganglion-celis are necessary only for the nutrition of 

 the nervous tissue, is not tlie true one. 



In Mormyrus there is another very important fact to be stated, which touches 

 also the nature of functions iu ganglion-cells. Besides the axis cylinders, the 

 electric cells in the spinal cord send out broad proces,ses, which communicate quite 

 regularly on such a large scale that there cannot be any doubt that these cells form 

 a complete system, being united for common work. 



The axis cylinder being a well-defined, not branched, process, the other uniting 

 processes must be considered protoplasmatic (in the sense of Deiters). Their 

 freqnent communications cannot have any other meaning than to warrant the 

 equality of action in the electric shock. Tliat statement being admitted, the proto- 

 plasmic processes of the cells must be conducting stnictures. If that is true in the 

 Mormyrus, there is no reason whatever why it should be otherwise in the rest of 

 vertebrate animals, although Golgi states that the protoplasmic processes are not 

 nervous. 



There is another proof in the organisation of Mormyrus regarding the same 

 object of combined action in the electric organs on both sides. The upper as well 

 as the lower electric nerves form a decussation outside the vertebral column, 

 like a chiasraa. As there is no other instance recorded that motor nerves cross 

 over from one side to the other through the median plane of the body, this shows 

 the immense power of adaptation to function (in the sense of Cha'ries Darwin) 

 "which nature is apt to work out. 



3. On the Leaf of Victoria Eegia. By Professor L. C. Miai-l. F.B.S. 



4. The Blood-vessels and Lymphatics of the Retina. 

 By James Musgrove, M.D., Demonstrator of Anatomy, Edinburgh University. 



AVhen we remember that the retina is to the eye what the sensitive plate is to 

 the photographic camera, it need hardly be wondered at that nature has provided a 



