SENSE OF TASTE. 



737 



organs, termed gustatory bulbs, or taste-buds. These are flask-shaped bodies 

 (Fig. 254), which are disposed 



in a zone encircling the sides FlG 2 r>4. 



of the papilla? circumvallatse 

 (Fig. 255), a few being also 

 found on the outer wall of the 

 vallecula, or that which looks 

 towards the papilla?. Schwalbe 

 estimated the number present 

 in one circumvallate papilla of 

 the Sheep at 480, and in one 

 such papilla from the Ox at 

 1760. They are also found, 

 but more irregularly distrib- 

 uted, upon the fungiform papil- 

 lae. The bulbs are composed 

 of groups of cells (Fig. 254), 

 which occupy flask-shaped cavi- 

 ties in the mucous membrane. The bottom of the cavity is formed by the 

 fibrous layer of the mucous membrane, its sides are composed of cells, and 

 the slender short neck perforates the corneal lamina, opening on the surface 

 by a small circular mouth, which maybe called the gustatory pore. The 

 length of the bulb is about 0.080 of a millimetre. The gustatory bulbs, 

 which completely fill these spaces, are composed of two kinds of cells. 

 Of these the outer, or investing cells (Fig. 254), from 15 to 30 in number, 

 are fusiform, have a well-defined nucleus, and are arranged concentrically 



Gustatory bulbs from the lateral gustatory organ of the 

 Rabbit. Mag. 450 diam. 



FIG. 255. 



FIG. 256. 



FIG. 255. Transverse section through a circum- 

 vallate papilla of a Calf, showing the arrangement 

 of the gustatory bulbs. 



FIG. 256. Termination of the gustatory nerves 

 of the Frog. Ramification of a nerve-fibre in the 

 nerve-cushion. Two goblet cells are seen, one 

 columnar, and ten forked cells. (Chromic acid 

 and glycerin. Mag. 600 diam.) 



to the surface in closely compressed rows. They inclose a group of cells 

 which are believed to be the true gustatory cells. These are long and thin 

 bodies, with a large vesicular nucleus, from which a peripheric process runs, 

 that either ends by an abruptly truncated extremity (rod or staff-cell), or in 

 a very fine point (needle-cells), the apices projecting for some distance 

 through the gustatory pore. The relations of these organs to the gustatory 

 nerves has not been quite satisfactorily made out ; but the finely medullated 

 branches of the glosso-pharyngeal nerve, containing small groups of gan- 

 glion-cells, have been observed to form plexuses beneath the papillae, from 



