viii Journal of Comparative Neurology. 



the internal cluster, thus showing that it is these cells from which the 

 nerves given off in the Fallopian canal arise, viz., the petrous nerve 

 and the nerve for the stapedius muscle. Section of the rami auricu- 

 lares anterior and posterior causes the degeneration of the remaining 

 cells of this internal cluster. Section of the main branches of the fa- 

 cial nerve, which run out over the masseter muscle and supply the fa- 

 cial muscles (except those supplied by the r. superior and by the auric- 

 ular rami) caused chromatolysis of all of the cells of the middle and 

 external groups, while section of the r. superior caused the degenera- 

 tion of the cells of the dorsal cluster. None of these experiments 

 caused any modification in the nuclei of either the III, the VI or the 

 XII nerves. 



The geniculate ganglion, it is now well established, is a cerebro- 

 spinal ganglion pertaining to the sensory root of the facial nerve (the 

 portio intermedia of Wrisberg). This ganglion, it is known, sends 

 fibers into the chorda tympani. Does it contribute fibers to any other 

 nerve ? This problem was attacked experimentally. In rabbits whose 

 facial nerve was sectioned immediately after its emergence from the 

 Fallopian canal the geniculate ganglion was stained and sectioned. 

 The ganglion cells are clearly of the cerebro-spinal type and most of 

 them were normal, yet a few were clearly degenerate. This last point 

 contradicts the similar experiments of Amabilino on the dog, which 

 were reviewed in the last issue of this Journal. It will be remem- 

 bered that the latter author found no degenerate cells after section of 

 the facial, but that only four-fifths of the cells degenerate after section 

 of the chorda tympani. Van Gehuchten thinks that the small number 

 of cells which degenerate after section of the facial were overlooked 

 by Amabilino. 



III. The third article is devoted to the IX and X nerves. It is 

 preceded by a long historical review which brings out sharply the great 

 diversity of opinion regarding the nuclei of these nerves. Section of 

 the vagus roots results in chromatolysis of cells throughout the dorsal 

 nucleus and thus permits an accurate determination of its limits. It 

 and the fasiculus solitarius run down into the ** intermediate zone" of 

 Onuf and Collins, rather than into the dorsal hornfregions, a point of 

 some morphological importance as the latter authors and the present 

 writer have both suggested. 



The ventral nucleus (n. ambiguus) is also degenerated throughout 

 its entire length, though there is a small column of normal cells running 

 along its inner side at the cephalic end (the ventral nucleus of the IX 

 root). The ventral nucleus of the vagus, like the dorsal nucleus, is 



