No. I.] SYMPATHETIC GANGLIA OF VERTEBRATES. 49 



were traced in every instance into a white ramus of the 

 ganglion. 



Fiber E may be explained somewhat more fully, as it ex- 

 plains, I believe, some observations made by Retzius (21) and 

 Smirnow (24). This fiber entered the eighth sympathetic gan- 

 glion through a white ramus, and could be traced through a 

 number of nodes of Ranvier, only two of which are shown. At 

 the second node shown in the figure there was given off a non- 

 medullated collateral branch, which terminated in a spiral and 

 pericellular plexus ; two nodes further on the fiber became non- 

 medullated, ultimately branching into two branches, each of 

 which terminated in a spiral and plexus. In a teased prepara- 

 tion, showing only the upper portion of the fiber, it may easily 

 be seen how one might be led to say that the spiral fiber 

 branched ^^ en 7"," as Retzius (21) has done, and diagrammed in 

 Fig. 3 of his article. Arnstein (20) and Smirnow (24) have 

 also described a branching of the spiral fibers ; they, it will be 

 remembered, assume that the spiral fiber has a peripheral course. 

 Such observations were made, I believe, on only partially stained 

 fibers. Whenever I was able to trace a spiral fiber to a medul- 

 lated fiber which had a peripheral course, such medullated fiber 

 always terminated in a spiral in some more distal portion of the 

 ganglion. 



The anastomosis between pericellular baskets of adjacent 

 ganglion cells, described by Smirnow (24) and long ago men- 

 tioned by Courvoisier (13) and others, I have never seen in 

 sections. In methylene blue preparations of whole ganglia, 

 cleared in glycerine, I have now and then seen what might 

 be regarded as an anastomosis between two baskets. It would 

 not, it seems to me, deserve the importance given it by 

 Smirnow (24). 



The observations above mentioned seem to me to present 

 very strong evidence in favor of the hypothesis long ago 

 expressed by Ehrlich (18) and Retzius (21), namely, that the 

 spiral fiber was the ending of a cerebro-spihal fiber. They seem 

 to me to show also that the course of the spiral fiber, after it 

 leaves the straight process, is centralward. I have attempted 

 by the degeneration method to determine this more clearly by 



