130 



PHYSIOLOGY 



CHAP. 



The hairlets of a taste-bud unite within the pore into a small 

 brush that projects on to the surface of the mucous membrane. 



In the depth of the taste-bud there are a certain number of non- 

 medullated nerve-fibres, which are distributed as an arborescence 

 between its cells (intragemmal or intrabulbar ramifications) and 

 also between the cells of the papilla round the bud (intergemmal 



I n . 56. 4 alia I'l'iui taste-buds of rabbit ","'. (En^linanii.) t>, four gustatory cells ; 

 h, two gustatory cells and one sustentaculai cell ; c, three siistrntarnlar cells. 



or peribulbar ramifications). Some authors (Fusari and Panaschi) 

 stated that the gustatory cells are in direct communication with 

 nerve-fibres and thus form the cells of origin of the peripheral nerve- 

 fibres (as occurs for the olfactory mucous 

 membrane, infra). But the latest researches 

 of Retzius and Lenhosse'k confirm the con- 

 clusions of Sertoli (1673) and Krohn (1875), 

 that the nerve-fibres are merely in simple 

 contiguity with the epithelial cells of the 

 taste-bud, and penetrate between and branch 

 round them (Fig. 56). 



The nerve bundle that penetrates the bud, 

 and the fibres that run to the flat epithelium 

 FIG. 56. TWO isolated gus- of the papilla, come from a very fine sub- 



tatory cells and one sus- -.i T i i i_ i j_ 



tentacular c.-ii from a epithelial nerve-plexus which contains numer- 



to^ffiuSalii 6 "^ ous sma11 cells of a neural character, although 

 them in ciub-shaped bulbs! this has been contested by some authors (Figs. 



(Arnstein ) / \ o 



52, 53). This plexus receives nerve-fibres from 

 a second plexus at the base of the papillae, which is formed from the 

 fibres of the glossopharyngeal and chorda tympani nerves. This 

 second plexus contains ganglion cells of different forms, some of 

 which are in relation with the cervical nerves, others with the 

 sympathetic system. The work of Kiesow and Nadoleczny and 

 of Schlichting has recently confirmed the fact that the chorda 

 tympani contains gustatory fibres. 



That the taste-buds really represent the. peripheral organs of 

 taste is proved by the fact that they lie in the oral cavity, and in 

 those papillae alone from which taste sensations can be excited, 



