92 Journal of Comparative Neurology. 



which opinions differ. Without attempting to discuss this point 

 here, I may say that I have regarded them simply as accumula- 

 tions of the neuroplasma, and the fine thread uniting the glob- 

 ules, as the ultimate fibrillae of the respective fiber. The obser- 

 vations which have suggested this hypothesis are briefly these : 

 In fresh methylen-blue preparations in which the sympathetic 

 nerves were well stained, examined as soon as the tissue was 

 removed from the body, I have often noticed that the varicose 

 enlargements, both on sympathetic fibers and ultimate branches 

 of the cerebro-spinal nerves, are far less numerous than when the 

 preparations are exposed to the air sometime before they are 

 studied or when such examination is deferred until the tissues are 

 fixed. The method of their development I have explained to 

 myself to be the following, — when the nerve fiber begins to 

 break down, the semi-fluid neuroplasma collects in small glob- 

 ules, which usually stain quite deeply; the more resistant ulti- 

 mate fibrillae unite the small globules, and give us the appear- 

 ance commonly described as a varicosity of the fibers. 



Very characteristic for non-medullated sympathetic fibers, 

 that is neuraxes of sympathetic neurons not invested with mye- 

 lin, is the presence of a large number of sheath-nuclei; nuclei of 

 the sheath of Schwann. 



These are much more numerous than in a medullated 

 nerve fiber, where, as is well known, usually only one nucleus 

 is found in an inter-nodal segment. These nuclei are often rel- 

 atively large and when stained with methylen-blue, as they 

 sometimes are, they may simulate a ganglion cell. In thin sec- 

 tions, however, and by double staining, their true nature may 

 be revealed. The neuraxes of the neurons of a given sympa- 

 thetic ganglion wind their way between the ganglion cells, to- 

 ward the periphery of the ganglion, and enter one of the 

 nerve trunks leaving the ganglion. 



Lenhossek (24) and Dogiel (25) have observed that now 

 and then such neuraxes give off one or several collateral 

 branches, while yet within the ganglion, which, as Dogiel 

 states, may branch between the ganglion cells into further 

 branches ; their mode of ending is however not known. 



