SENSATIONS OF TASTE AND SMELL. 



295 



the same ganglion through the tympanic nerve, the small super- 

 ficial petrosal, and the otic ganglion. A report by Gushing* 

 of the results of removal of the Gasserian ganglion in thirteen 

 cases throws much doubt upon these views. This author made 

 careful examinations of the sense of taste, not only immediately 

 after the operation, but for a long period subsequently. He 

 states that in no case was there any effect upon the sense of taste 

 in the posterior third of the tongue. We may believe, therefore, 

 that the taste fibers of this part arise immediately from the ganglion- 

 cells in the petrosal ganglion and enter the brain with the roots of 

 the nerve to terminate in its sensory nucleus in the medulla. 



Fig. 120. Schema to show the course of the taste fibers from tongue to brain. 

 (Gushing.') The dotted lines represent the course as indicated by Cushing's observations. 

 The full black lines indicate the paths by which some authors have supposed that these 

 fibers enter the brain in the trigeminal nerve. 



Regarding the anterior two-thirds of the tongue, the lingual region, 

 it was found that in some cases there was at first a loss of acuity of 

 taste or even an entire disappearance of the sense, but subsequently 

 it returned. It would seem, therefore, that the loss of taste de- 

 scribed after removal of the Gasserian ganglion is an incidental 

 result the cause of which is not entirely clear. Gushing attributes 

 it to a postoperative degeneration and swelling in the fibers of the 

 lingual nerve, which affect the conductivity of the intermingled 

 fibers of the chorda tympani. Since, however, there is no perma- 



* Gushing, " Bulletin of the Johns Hopkins Hospital," 14, 71, 1903. Gives 

 also the surgical literature. 



