THE SENSES. 



561 



siform cells (encasing cells]. The gustatory cells terminate in fine spikes 

 not unlike cilia, which project on the free surface (Fig. a, 373). 



These bodies also occur side by side in considerable numbers in the 

 epithelium of the papilla foliata, which is situated near the root of the 

 tongue in the rabbit, and also in man. Similar taste*goblets have been 

 observed on the posterior (laryngeal) surface of the epiglottis. It seems 

 probable, from their distribution, that these taste-goblets are gustatory 

 in function, though no nerves have been distinctly traced into them. 



Other Functions. Besides the sense of taste, the tongue, by means 

 also of its papillae, is endued (2) especially at its side and tip, with a 

 very delicate and accurate sense of touch which renders it sensible of the 

 impressions of heat and cold, pain and mechanical pressure, and conse- 

 quently of the form of surfaces. The tongue may lose its common sen- 

 sibility, and still retain the sense of taste, and vice versa. This fact 

 renders it probable that, although the senses of taste and of touch may 



FIG. 373. Taste-goblet from dog's epiglottis Oaryngeal surface near the base), precisely similar 

 in structure to those found in the tongue, a, depression in epithelium over goblet; below the letter 

 are seen the fine hair-like processes in which the cells terminate ; c, two nuclei of the axial (gusta- 

 tory) cells. The more superficial nuclei belong to the superficial (encasing) cells; the converging 

 lines indicate the fusiform shape of the encasing cells. X 400. (Schofield.) 



be exercised by the same papillae supplied by the same nerves, yet the 

 nervous conductors for these two different sensations are distinct, just 

 as the nerves for smell and common sensibility in the nostrils are distinct; 

 and it is quite conceivable that the same nervous trunk may contain 

 fibres differing essentially in their specific properties. Facts already 

 detailed seem to prove that the lingual branch of the fifth nerve is the 

 conductor of sensations of taste in the anterior part of the tongue; and 

 it is also certain, from the marked manifestations of pain to which its 

 division in animals gives rise, that it is likewise a nerve of common sen- 

 sibility. The glosso-pharyngeal also seems to contain fibres both of 

 common sensation and of the special sense of taste. 



The functions of the tongue in connection with (3) speech, (4) mas- 

 tication, (5) deglutition, (6) suction, have been referred to in other 



chapters. 



36 



