CRANIAL SYMPATHETIC GANGLIA IN THE RAT 191 



In connection with some previous observations of the writer on 

 changes occurring in the foliate papilla of the rabbit after section 

 of the glossopharyngeal nerve, opportunity has existed to observe 

 any changes in ganglion cells of this region (undoubtedly IXth 

 territory) following section. No change and no decrease in 

 ganglion cells has been noted after complete disappearance of 

 taste buds. Circumstantial evidence then would seem to indicate 

 that the general arrangement of these ganglia followed somewhat 

 the scheme of those of the intestinal plexuses, and that they are 

 not entirely dependent on external (cerebrospinal) stimuli. This 

 observation accords with that of Prentiss ('04). The latter 

 noted no changes in cells or fibers (aside from large medullated 

 fibers) in the perivascular and subepithelial networks in the oral 

 epithelium of the frog after section of the palatine branches of 

 the facialis. Prentiss' observation as to the existence of such 

 networks is interesting in connection with the reported absence 

 of cranial sympathetic ganglia — save perhaps a ciliary ganglion— 

 in anura. 



The ramus pharyngeus IX, as previously stated, is much larger 

 than the corresponding vagus branch. Although anastomoses 

 with the ramus pharyngeus vagi occur at early stages, I have 

 been able to trace the respective branches quite clearly up to 

 and including sixteen-day stages. At this time certain elongate 

 elements are found in a ganglion-like cluster; a rounding out of 

 the nucleus is to be noted together with the development of a 

 scanty but characteristic cytoplasm, and in seventeen-day 

 embryos large numbers of ganglion cells are to be found in the 

 nerve trunk and among its peripheral terminations (fig. 12); 

 these cells are evident throughout the entire trunk from the 

 ganglion petrosum peripheralward, and one is consequently 

 forced to assume that they originate from migrating cells of the 

 glossopharyngeus. A sympathetic anastomosis is, to be sure, 

 present at this time, but the position of the developing nerve 

 cells of the ramus pharyngeus IX forces one to exclude this 

 anastomosis as a factor in their production. 



The adult nervus tympanicus or nervus palatinus IX is quite 

 closely associated with fibers from the internal carotid nerve; 



