Journal of comparative neurology . of such fibers into the their course in the neck, although the two ner\-esare contained in a conunon sheath, no interchange of fiberscould be traced. At the level of tlic inferior cervical ()ganglion of the sympathetic, however, the association of thevagus and sympathetic is veiy close, and numerous large bun-dles of sympathetic unmyelinated fibers can be seen in serialsections entering and leaving the vagus tiimk. If, then, anyconsiderable proportion of the unmyelinated fibers in the thoracic\agus of the dog have their origin in the s^
Journal of comparative neurology . of such fibers into the their course in the neck, although the two ner\-esare contained in a conunon sheath, no interchange of fiberscould be traced. At the level of tlic inferior cervical ()ganglion of the sympathetic, however, the association of thevagus and sympathetic is veiy close, and numerous large bun-dles of sympathetic unmyelinated fibers can be seen in serialsections entering and leaving the vagus tiimk. If, then, anyconsiderable proportion of the unmyelinated fibers in the thoracic\agus of the dog have their origin in the s^^upathetic trunk,they nuist arise from cells in the inferior cervical ganglion ,or ganglion stellatum, METHODS The right vagus ner\e was se\-ered in a number of dogs. Insome cases it was separated from the sympathetic tnmk highin the neck and about an inch of the vagus nerve was removed(fig. 1, A). There would then be no interference with fibers THE JOLKXAL OF COMTAR-VTIVE XEUROLOGV, VOL. 26, XO. 4 424 MARTIN 11. CHASE. 4 b. THE VAGUS XERVE 425 from the superior cervical ganglion, the sympathetic trunk orinferior cervical ganghon. In other cases about an inch of combined vagus and sym-pathetic trunk was removed in the midcervical region (fig. I, B).Such a procedure would cut off any fibers to the vagus from thesuperior cervical ganglion, but would in no way interfere withfibers from the inferior ganglion. The dogs were autopsied after 2 to 8 weeks and jiortions ofthe nerves studied after pre])aration by the pyridine silvermethod fRanson 11. 12) and the osmic acid method. CHANGES AKTEIl .SIXJTIOX OF THE VACUS ALONE HKUI INTHE NEfK Sections fi-oiii llie right \agus of a dog autoi)sietl five weeksafter removal of a ])oition of \]\o upper cervical vagus, the .sym-pathetic l)eing left intact, show definite degenerative cross section stained l)y the pyridine silver method, taken Via. 1 Diagram of tlic ri<ili( iiorvo in the (I<ir Jin. L From a .soctio
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Keywords: ., bookauthorw, bookcentury1900, bookdecade1910, booksubjectmedicine
