yS HUBER. [Vol. XVI. 



which I have corroborated, the conclusion may be drawn that 

 neuraxes of sympathetic neurons (especially those surrounded 

 by a thin layer of myelin) end in the intercellular plexuses of 

 sympathetic ganglia, probably on the dendrites of sympathetic 

 cells ; and, finally, Ramon y Cajal's (36) and Dogiel's (49) 

 observations on the ending of sympathetic nerve fibers in the 

 spinal ganglia of Mammalia support the view that the neuraxes 

 of sympathetic neurons end in the spinal ganglia. 



4) The cell bodies of sympathetic neurons are surrounded by 

 a nucleated capsule, which apparently has the same structure 

 in all vertebrates. 



5) In the sympathetic ganglia of all vertebrates studied by 

 others and myself {speaking here of results obtained with either 

 the Golgi or the methylene blue method), medullated fibers 

 ending in pericellular intra-capsular plexuses have been found. 

 These are, in all instances described, of essentially the same 

 structure. I am well aware, as the accompanying plates may 

 show, that the relation of the pericellular plexuses to the cell 

 bodies of the enclosed sympathetic neurons varies somewhat in 

 the different vertebrates, as do also the course, structure, and 

 relation to other processes of the nerve fibers ending in such 

 pericellular plexuses ; yet these differences are not essential 

 and important. The question now arises, What is the origin 

 of the medullated fibers thus ending in the pericellular plexuses.? 

 " Bei der Ermittelung der schwierigen, hier zur Sprache kom- 

 menden Verhaltnisse haben sich " (as Kolliker aptly states) "die 

 Physiologic und die feine Anatomic bruderlich die Hand ge- 

 reicht." The anatomical side of the question has been repeat- 

 edly touched in the preceding pages, where it may have been 

 seen that abundant observations have been made, both with the 

 Golgi and methylene blue method, to show that such medullated 

 fibers enter the ganglion either through the white rami (chain 

 ganglia) or through some nerve root of the ganglion. Once in 

 the ganglion, the medullated fibers have been shown to branch 

 and even rebranch before ending in the pericellular plexus. 



Physiologists have long known that all sympathetic effects, 

 which may be produced by stimulating a sympathetic nerve in 

 any region, may also be produced by stimulating some spinal 



