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processes employed. The prolongations springing from these 

 cells, Avhich are generally multipolar, are nothing more than 

 bundles of primitive fibrils. Do certain of these bundles (or 

 fascicles) unite directly with the nucleus of the ganglion-cell 

 or not ? Histologists are now much occupied by this ques- 

 tion. Harless has answered it in the affirmative. More 

 than twenty years have passed since his researches on the 

 electric organ of the Torpedo were made. Then came MM. 

 Axraann, Lieberkuhn, Guido, Wagner, and Owsjannikow, 

 who also maintained, in the most positive manner, the union 

 of nervous fibres with the nuclei of ganglion-cells. They found, 

 it is true, ardent contradictors in Rud. Wagner and MM. 

 Valentin and Stilling, who have made the majority of histo- 

 logists accept the absence of all direct relation between the 

 nuclei of cells and the fibres or prolongations springing from 

 the bodies of these cells. Nevertheless, in 1864, M. From- 

 mann revived the discussion by his researches on the motor 

 cells of the lumbar region of the spinal cord. He described a 

 complete system of fibres, some finer and others coarser, which 

 not only envelope the nucleus, but actually penetrate into it 

 to the nucleolus. According to this author the very fine fila- 

 ments that he calls nucleolar filaments (Kern Korperchen- 

 f aden) cross the nucleus to spread out in the body of the cell ; 

 a part of them are enveloped with a sort of sheath furnished 

 by a prolongation of the nucleus ; in consequence he calls this 

 sheath the nuclear tube (Kernrohre). A short time after, 

 Arnold published some very similar observations relative to 

 the sympathetic ganglion-cells in frogs. MM. Hensen, Koll- 

 mann, Arnstein, Courvoisier, Guy, and Bidder have likewise 

 observed these filaments in the sympathetic cells. On the 

 other side, M. Arndt, who has also seen a sort of thread in 

 communication with the nucleus, maintains that it does not 

 arise from the nucleus itself, but from a clearer zone which 

 envelops this structure. The union of this filament with the 

 nucleolus would then be a simple appearance, resulting from 

 an optical illusion. It is this, it appears, which Harless un- 

 derstood so far back as the year 184G. " The nervous fibre,^' 

 says he, " never penetrates into the ganglion-cell in the plane 

 of its largest circle, but it always describes a little arc, so as to 

 arrive at the nucleus ; also, when you bring this latter struc- 

 ture in focus, you see the section of the fibre projecting itself 

 like a nucleolus on the nucleus. ^^ Whatever may be said 

 about these observations, the penetration of fibres into the 

 interior of nerve-cells seems less inexplicable now that the 

 body itself of these cells is ascertained to be entirely formed 

 by extremely thin fibrils blended and interwoven in different 



