48 M. K. CHASE AND S. W. R ANSON 



containing the bulbar fibers remain for the most part outside of 

 the nodose gangUon and mingle with the vagus fibers below it. 

 In some rabbits he found the vagus and bulbar accessory fibers 

 intermingled above the level of the nodose ganglion. 



From what has been said in this and preceding paragraphs it 

 will be apparent that no such thing as the internal branch of the 

 spinal accessory exists in the dog. According to Van Gehuchten 

 and Molhant, it is also absent in man and in the rabbit. The 

 old description of the accessory dividing into an internal and 

 external branch, the former of which joins the vagus, is based on 

 artificial conditions produced by the dissector's knife. The vagus 

 and accessory nerves fuse into a common trunk at the level of 

 the jugular foramen. The so-called spinal part maintains its 

 individuality throughout this common trunk, beginning as the 

 spinal root and ending as the external branch. Composed as it 

 is almost entirely of large medullated fibers it differs markedly 

 from the rest of the common trunk. The bulbar portion, com- 

 posed chiefly of fine medullated fibers, maintains its individuality 

 for a varying distance in the common trunk and then mingles 

 with the fibers from the vagus rootlets. Since the bulbar fibers 

 of the accessory have an origin from the medulla similar to that 

 of the vagus fibers, since they form rootlets exactly like the vagus 

 rootlets of Type T, and since they become fused with the vagus 

 trunk and distributed in its branches, it would be more proper 

 to speak of the bulbar portion of the accessory as a part of the 

 vagus which for a short distance runs in company with the 

 accessory nerve. 



In serial sections through the upper part of the ganglion a 

 large bundle of good-sized medullated fibers can be seen collect- 

 ing at one side. At about the middle of the ganglion this bundle 

 leaves the vagus as the superior laryngeal nerve. The structure 

 of this and the pharyngeal branch will be taken up in another 

 place. 



In' the nodose ganglion the number of non-medullated fibers 

 appears to be much greater than at higher levels. This may be 

 due to an increased intensity of staining bringing out fibers that 

 were unstained at a higher level. It is, no doubt, in part due 



