THE SYMPATHETIC SYSTEM OF NERVES. 543 



of the Rabbit and of the Guinea-Pig possess a double nucleus, 

 an observation, of the correctness of which we may satisfy our- 

 selves by the simplest preparation of a sympathetic ganglion 

 from a Rabbit. I have myself on many occasions observed the 

 presence of two nuclei in the sympathetic nerve cells of the Cat 

 and Dog, and of Man. Bidder admits the presence of a com- 

 munication between the two nuclei of the double nucleated 

 cells, which is established by a fine thread or filament, and I 

 can thoroughly corroborate his statement from my own obser- 

 vation. In nuclei that had been isolated from the cell substance 

 I have likewise found these " nucleus connecting fibres," so 

 that it was impossible to mistake them for any folding of the 

 sheath, coagulation in the substance of the nerve corpuscle, or 

 the like. 



The position of the nucleus is very variable, both in regard 

 to the situation which it takes up in the matrix, and also in the 

 relations of one nucleus to another when two are present. In 

 some instances the nucleus is displaced towards the surface of 

 the cell, so that it even causes it to project, whilst in other cases 

 it occupies the centre. When the nuclei are two in number, 

 they vary still more in their position, lying sometimes nearly 

 in the same plane, and at others being situated in various 

 planes beside or subjacent to one another, separated sharply 

 from each other by cell substance. Those cases in which the 

 nuclei lie in nearly the same plane are exceedingly well adapted 

 to show the above-mentioned fibres of communication between 

 the nuclei. 



Like the cells themselves, the nuclei also exhibit no incon- 

 siderable differences in regard to their size. In researches 

 made upon the nerve corpuscles from the ganglia of various 

 animals, this relation is not to be overlooked. Thus we find, in 

 scrutinizing the everywhere abundant nerve cells in the nerve 

 plexuses accompanying the large vessels of the abdomen in the 

 Frog, sometimes large cells with only one big nucleus ; some- 

 times large cells with a single big and many small nuclei (polar 

 nuclei, Courvoisier) ; thirdly, large cells filled with a number of 

 small nuclei ; fourthly, small cells, the interior of which is 

 almost entirely occupied by the nucleus, the investing zone of 

 cell substance being very thin; and, lastly, cells in which a 



