No. I.] SYMPATHETIC GANGLIA OF VERTEBRATES. 55 



Dogiel is inclined to think that the cells described by him do 

 not belong to neuroglia tissue. He likens them to the branched 

 connective tissue elements, which are found on the membrana 

 propria of gland alveoli, which, as he states, are also occasion- 

 ally stained in methylene blue. The cells in question have 

 never been stained by me in methylene blue. This may be 

 due to the fact that in all my work the methylene blue solu- 

 tion was injected into the living animal, in which case, as is 

 well known, many elements do not stain as readily as when the 

 methylene blue solution is added directly to the freshly removed 

 tissues. My only reason for suggesting that the nuclei found 

 within the capsule of many of the sympathetic cells of Reptilia 

 are nuclei of neuroglia cells is based on some observations 

 made on ganglia hardened in Miiller's fluid, imbedded in par- 

 affin and sectioned, the sections being then stained in haema- 

 toxylin and double-stained in the acid fuchsin — picric acid 

 solution suggested by Van Gieson. In such sections are seen 

 a large number of fine fibrillae, which seem to be more or less 

 intimately connected with the nuclei above mentioned. These 

 fibrillae are not, I believe, nerve fibrillae, belonging to the 

 pericellular plexus presently to be described ; their smooth and 

 regular contour and their apparent connection with the nuclei 

 would exclude such a supposition. Time has not been at my 

 disposal to consider these nuclei more fully. I mention the 

 above hypothesis in the hope that it may stimulate further 

 inquiry into their structure. 



In the sympathetic ganglia of Reptilia, stained in methylene 

 blue, medullated nerve fibers, which enter the ganglia through 

 their rami, are abundantly found. Many of these medullated 

 fibers have been traced into intra-capsular, pericellular plex- 

 uses. Such pericellular plexuses may be described under two 

 heads: 



a) Simple pericellular plexuses, without spiral fibers, sur- 

 rounding, as a rule, the cell body of multipolar or bipolar 

 ganglion cells. 



b) Complex pericellular plexuses, with spiral fibers, more 

 often found surrounding the cell body of the large unipolar 

 cells above mentioned. 



