TASTE. 875 



cous glands and follicles beneath it, some of which open into the bot- 

 tom of the foramen caecum. 



The corium, or vascular part, of the circumvallate papillae (Fig. 

 70, c), and of the elevated rim, by which each is surrounded, is pro- 

 longed into numerous secondary papillae, which are buried in the thin 

 and smooth epithelial covering. The fungiform papillae likewise pre- 

 sent numerous little conical secondary papillae (6), covered by the 

 epithelium. The filiform papillae also have, at their points, numerous 

 secondary papillae (a), concealed in the thick brush of filamentous 

 epithelium. Besides these secondary papillae, found on the larger and 

 so-called compound papillae, numerous minute and simple papillae, re- 

 sembling the secondary papillae, exist everywhere, between the com- 

 pound papillae. 



Many of the muscular fibres of the tongue pass into the mucous 

 membrane and its papillae, presenting the peculiarity of dividing and 

 subdividing before they enter these parts. Both the compound and 

 simple papillae receive vessels and nerves. Each papilla contains one 

 or many vascular capillary loops, according to its size. In the fungi- 

 form and circumvallate papillae, especially, the nerves are very numer- 

 ous, arid, in the latter, very large; they are usually said to terminate 

 in loops ; but it is possible that many at least end by fine free ex- 

 tremities, a mode of termination seen in the tongues of some animals. 



Each half of the tongue is supplied by three nerves. Of these, two 

 are sensory, viz., the lingual or gustatory branch of the inferior max- 

 illary division of the fifth cranial nerve, and the lingual branch of the 

 glosso-pharyngeal. The former is distributed to the mucous mem- 

 brane and papillae at the forepart and sides of the tongue, the latter 

 to the mucous membrane at the base and side of the tongue, and, it is 

 said, especially to the circumvallate papillae. The remaining nerve, 

 the hypoglossal, or ninth cranial nerve, supplies the muscular sub- 

 stance of the tongue, and is the motor nerve of this organ. 



The soft palate, its central depending uvula, and its lateral arches, 

 or pillars, will be hereafter described with the other parts concerned 

 in deglutition. Its mucous membrane, which is smooth and delicate, 

 and provided with short soft papillae, and numerous glands, is sup- 

 plied by branches derived from the superior maxillary division of the 

 fifth cranial nerves, and also by branches from the glosso-pharyngeal 

 nerves. 



Taste. 



The true sense of taste in the tongue is confined to the posterior 

 third of the dorsum of that organ, the under surface of its apex, arid a 

 line along its edge, about a quarter of an inch wide. It is most 

 marked on the hinder part of the organ. It also resides in the ante- 

 rior pillars of the fauces, the soft palate near its attachment to the hard 

 palate, and the hinder portion of the latter. (Stich and Klaatsch.) 



The experiments of Reid show that the glosso-pharyngeal is a nerve 

 of special sense, as well as of common sensation, and also an afferent 

 reflex nerve; for not only are unmistakable signs of pain produced 

 by irritation of the nerve in the living animal, but division of this 



