THE ORGAN OF TASTE. 



1435 



Fig. I 196. 



Outer taste-pore 



supporting cells, somewhat blunted and flattened and beset with a narrow cuticular 

 zone, are closely grouped to bound the annular opening of the inner taste-pore, 

 through which project the stiff hair-processes of the gustatory cells-. Their deeper 

 or central ends are prolonged into one or more protoplasmic processes which unite 

 with similar extensions of the basal cells, as the peculiar supporting cells at the base 

 of the bud are called. 



The basal cells are modified sustentacular elements, probably epithelial in nature, 

 which occupy the lower fourth of the buds, resting upon the subjacent epithelium 

 and, in turn, affording support for the elongated cells. Although differing in size 

 and details of form, the basal cells are provided with oval nuclei and are generally 

 more or less branched. By means of their protoplasmic processes they are united 

 with the central ends of the longitudinally disposed supporting and gustatory cells, 

 with one another and with the surrounding epithelial cells. The number of basal 

 cells in each bud is small, often only two or three and seldom more than half a 

 dozen being present (Graberg\ Kallius'^). 



The percipient elements, the gustatory cells, are irregularly arranged between 

 the more deeply placed supporting cells and enclosed within a shell formed by the 

 more superficial ones. They are long and fusiform, reaching from the base of the 

 bud to the inner taste-pore, through which 

 the stiff hair-like processes that cap their 

 outer ends project. Their slender nuclei, 

 rich in chromatin and deeply staining, 

 occupy the thickest parts of the cells, 

 which beyond the nucleus are continued 

 in either direction as thin processes. The 

 peripheral ones, as noted, extend not only 

 as far as the inner taste-pore, but through 

 the latter and into the canal by means of 

 the gustatory hairs into which the taste 

 cells are prolonged. The centrally directed 

 ends are usually much the shorter and 

 join the processes of the basal cells. The 

 number of gustatory cells within a single 

 taste-bud varies, in exceptional cases only 

 two or three being present, but more 

 often they are almost as numerous as the 

 supporting cells (Graberg). 



The capillary clefts observed within 

 and around the taste-buds — the inti^a- siib- and peri-bulbar juice-spaces described 

 by Graberg — are regarded by some as existing during life and, therefore, not as 

 artefacts. To these intercellular clefts the last-named authority attributes the func- 

 tion of insuring and facilitating an active lymph-circulation within and around 

 the taste-buds, whereby is effected the prompt removal of foreign substances that 

 might prove deleterious if too long retained in close relation with the delicate 

 sensory elements. 



Hermann has shown that the taste-buds are the seat of continual degeneration 

 and repair, sometimes, indeed, entire buds undergoing regression. Whether such 

 destructive processes are to be ascribed directly to the invasion of leucocytes, al- 

 though the latter are normally found in insignificant numbers within the buds, is still 

 a subject of discussion. 



The nerves distributed to the gustatory bodies are the fibres of the glosso- 

 pharyngeal, the nerve of taste. From the rich subepithelial plexus numerous twigs 

 ascend into the epithelium, one set going directly into the taste-buds and the other 

 ending within the surrounding tracts of epithelium. Since the last set — the inter- 

 bulbar fibres — probably have no concern with the impressions of taste and serve to 

 convey sensory stimuli of other value, it suffices to note that after repeated division 





Peripheral 

 supporting cell 



Gustatory cell 

 Central 

 supporting cell 



Lymph-space 



Basal cell 



Diagrammatic section illustrating architecture of 

 taste-bud. {Graberg.) 



^ Anatomische Hefte, Bd. xii., Hf. 2, 1899. 



* Bardeleben's Handbuch d. Anatomie des Menschen, Lief. 13, 1905. 



