46 HUBER. [Vol. XVI. 



rectly answered by Retzius (21), who states that, as a rule, the 

 fibrillae form a closed network, but that now and then free- 

 ending fibrillae may be observed. In PI. Ill, Fig. 8, which 

 represents a portion of a section of the sympathetic ganglion 

 on the second spinal nerve of a frog, in which the structures 

 were very well stained in methylene blue, I have indicated by 

 the letter e a number of instances where fibrillae seem to end 

 free, usually in a small nodular enlargement. That the net- 

 work is continuous with the spiral fiber seems evident to all 

 investigators, with the exception of Feist (23), who have studied 

 the sympathetic ganglia of Amphibia with the methylene blue 

 stain. Most often the network and spiral are alone stained, 

 and in sections of 20 /u, to 40 yu- thickness the spiral fiber may 

 often be traced with the utmost clearness through the " gran- 

 ular mass" into the fibrillae of the network ; the granular mass, 

 g^ of PI. Ill, Figs. 8-10, forming a more densely woven portion 

 of the network, as has been pointed out by Retzius (21). 



My own observations on the course of the spiral fiber after 

 it leaves the straight process lead me to conclude that its course 

 is centralward; or, to express it in another form, the pericellular 

 plexus and spiral fiber are parts of a neuron, the cell body of 

 which is situated more centrally than the respective sympathetic 

 ganglia, in which the structures are found. These conclusions 

 are based on observations made on ganglia prepared in the 

 following way: a small quantity (| to i c.cm.) of a i^ solu- 

 tion of methylene blue was injected into the circulation of a 

 small frog. At the expiration of about an hour the entire sym- 

 pathetic system was exposed. The entire sympathetic chain 

 on one side, with the rami communicantes and segments of the 

 spinal nerves from which they had their origin, was then 

 removed and placed on a slide moistened with normal salt. 

 As soon as the stain seemed developed as much as it would, 

 the preparation was fixed in ammonium picrate and cleared in 

 glycerine. When properly fixed and cleared, the entire chain 

 was placed on a slide, where all the surrounding tissues were 

 removed with teasing needles, care being taken not to tear any 

 of the rami from the ganglia. The entire chain, thus freed 

 from all connective tissue, was then mounted in ammonium 



