CRANIAL SYMPATHETIC GANGLIA IN THE RAT 167 



The portion of Hoffmann's explanation most deserving of 

 attention is the part concerned with the possible double nature 

 of those cranial ganglia which have generally been considered 

 similar in structure to the posterior root ganglia of the trunk 

 region. Histological evidence would seem to rest on the recog- 

 nition of multipolar cells, possibly bipolar cells in the ganglia 

 concerned. Such evidence is apparently scanty (Cajal and 

 Oloriz. '98; Cajal, '06) in the case of the cranial sensory ganglia, 

 but there exists considerable evidence for the presence of multi- 

 polar cells in the posterior root ganglia of the spinal nerves. 

 Such, for example, is the contention of Kolliker ('96) (quoting 

 Disse, '93), Lenhossek ('94), Spirlas ('96), Dogiel ('97), Hardesty 

 ('05), and Ranson ('12). Dogiel ('97) examined hundreds of 

 ganglia, finding only occasionally those containing multipolar 

 elements, and then but one, two, or three cells per series. Of 

 the numerous minutely described cell-types indicated in Dogiel 

 ('08), his type XI most nearly approaches our ordinary notion 

 of a sympathetic ganglion cell, but in the absence of any knowl- 

 edge as to the termination of the so-called 'Hauptfortsatz' and 

 considering the doubtful nature of the 'Dendritenahnliche 

 Fortsatze,' an assignment of these cells to the sympathetic would 

 be premature. Cajal ('06) did not consider bipolar cells found 

 in the vagus ganglion as sympathetic. 



Despite the lack of adequate histological evidence, certain 

 morphologists still prefer to interpret the geniculate, petrosal, 

 and nodosal ganglia as in part sympathetic. Such is the con- 

 clusion of Hardesty ('14). F. T. Lewis ('13) states that since 

 upon the glossopharyngeal and vagus nerves two ganglia exist — 

 a ganglion of the root and a ganglion petrosum (IX) or nodosum 

 (X), the latter ganglia occupying a position somewhat comparable 

 in relation to the root ganglia as do ganglia of the sympathetic 

 chain to dorsal root ganglia in the spinal region — his tentative 

 attitude is to regard these inferior ganglia (petrosal and nodose) 

 as sympathetic ganglia. Professor Hardesty has been so kind 

 as to furnish me with certain physiological references bearing 

 particularly on the vagus ganglia (Garrey, '12), possibly indicat- 

 ing a vagus influence on the heart independent of cardiac ganglia, 



