ANATOMY OF THE GUSTATORY ORGAN 127 



suspected of including gustatory fibers, is really devoid 

 of them. These fibers at most occur in the facial, glos- 

 sopharyngeal and vagus nerves, but none of these nerves 

 is exclusively gustatory. 



8. Relation of Gustatory Nerve-fibers to Taste-buds. 

 It is an interesting and significant fact that on the de- 

 generation of the gustatory nerve-fibers the taste-buds 

 associated with them should disappear. This state of 

 affairs, long ago demonstrated for mammals, has recently 

 been shown by Olmsted (1920a, 1920b) to occur also in 

 fishes. Meyer (1897) showed that thirty hours after cut- 

 ting the glossopharyngeal nerve in the rabbit the taste- 

 buds began to show a change and that by the end of seven 

 days most of them had disappeared. In the catfish Ami- 

 urus, according to Olmsted, the taste^buds on the oral 

 barbels begin to degenerate in a little over ten days after 

 the nerve to these organs has been cut and they com- 

 pletely disappear by the end of the thirteenth day. 

 Ranvier (1888) believed that in mammals the taste-buds 

 were destroyed by wandering cells, but Sandmeyer (1895) 

 and Meyer (1897) held the view that the gustatory cells 

 suffered dedifferentiation and changed into ordinary epi- 

 thelial cells. In Amiurus Olmsted has found strong 

 evidence in favor of the destruction of the cells of the 

 taste-buds by phagocytes thus supporting Ranvier 's 

 original opinion. 



Olmsted has shown, further, that on the regeneration 

 of a nerve in a denervated Amiurus barbel from which 

 all the taste-buds had disappeared, new buds reappear 

 coincident with the arrival of the nerve. With the de- 

 generation of the nerve and the loss of the taste-buds the 

 barbels lose their receptivity for sapid materials, nor 



