HuBER, Sympathetic Nemous System. 89 



that the capsule and the neurilemma of the neuraxis are con- 

 tinuous ; my own observations do not allow me to formulate 

 any definite opinion on this point. 



Dendrites. — The number and the arrangement of the den- 

 drites of sympathetic neurons vary greatly, even in the same 

 ganglion. As already stated, some few cells are unipolar ; this 

 is especially so in the larger ganglia. The single process pres- 

 ent, is of course the neuraxis. In amphibia cells of this char- 

 acter are the general rule for all ganglia, excepting those found 

 in the coats of the intestine. 



In sympathetic cells possessing dendrites, their number may 

 vary from one — bipolar cells — to ten or perhaps even more. 

 These dendrites may have their origin from any portion of the 

 cell body, as is the general rule, or several dendrites may arise 

 from one large process, from which springs also the neuraxis. 

 Cells of this character are prevalent in the larger ganglia of the 

 sympathetic system of the reptilia. 



The dendrites usually break up near the cell body into 

 secondary and tertiary branches, and undergo further and re- 

 peated divisions until exceedingly fine terminal branches are 

 reached. In well stained sections the dendrites form a very 

 complicated network, which is found between the ganglion cells. 

 This dendritic plexus is especially dense toward the periphery 

 of the ganglion, as has been shown by Dogiel (25) and described 

 by him as the "general peripheral plexus." The plexus formed 

 by the branching dendrite is always extra-capsular, as may 

 easily be seen in methylen-blue preparations double stained in 

 alum carmine. In preparations well stained the cell bodies of 

 the neurons are surrounded by a densely woven, basket-like 

 plexus, in which the dendrites of several neurons may take 

 part. 



Ramon y Cajal (20) has described such basket-like plexuses 

 as pericellular nests, and supposed this arrangement to be of 

 physiological importance, believing that the sympathetic neu- 

 rons were by means of it associated in their function. Dogiel 

 (25) has, however, and I think very justly, discredited this con- 

 clusion, and, while he describes and pictures such pericellular 



