THE TASTE-BUDS. 



385 



Jacobson that is present, in varying degrees of perfection, in all amniotic 

 vertebrates (Peter). In many animals possessing in high degree the sense 

 of smell, the organ is well developed and functions, serving possibly as an 

 accessory and outlying surface by which the first olfactory impressions are 

 received (Seydel). 



In man the organ is represented by a laterally compressed tubular 

 diverticulum, from 1.5-6 mm. in length, that passes backwards to end 

 blindly beneath the mucous membrane on each side of the nasal septum. 

 The median wall of the diverticulum is clothed with tall columnar cells 

 resembling those of the olfactory region, the characteristic olfactory cells, 

 however, being wanting. The epithelium covering of the lateral wall cor- 

 responds to that of the respiratory organ. In many animals possessing 

 acute olfactory sense, branches of the olfactory nerve are traceable to 

 Jacobson' s organ in which are found olfactory cells. 



THE TASTE-BUDS. 



In the description of the tongue and its papillae (page 144), reference is 

 made to the presence of specialized epithelial structures, the taste-buds, 

 that serve for the reception of gustatory stimuli. These bodies collectively 

 constitute the peripheral sense-organ of taste and as such will be here con- 

 sidered. 



As implied by their name, the taste-buds or calyciili gustatorii are irreg- 

 ular ellipsoidal or conical bodies, sometimes broadly oval but more often 



Lymphoid area 



Posterior limit of 

 papillary area 



Circumvallate 

 papillae 



Palatine arch 

 Foliate papillae 



Fungiform, 

 surrounded by 

 filiform papillae 



FIG. 434. Part of dorsum of the tongue, showing varieties of the papillae ; natural size. 



slender in outline, and in the adult measure from 70-80 it in length and 

 about half as much in breadth. Since they lie entirely within the epithelium 

 clothing the mucous membrane, the necessary access to the interior of the 

 buds is afforded by minute pore-canals, each of which, beginning on the free 

 surface at the outer taste-pore, leads through the intervening layer of epithe- 

 lium to the inner pore that caps the subjacent pole of the bud. By means 

 oi these canals the sapid substances dissolved in the fluids of the mouth 

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