460 MEJIBRANE LINING THE HARD OR BONY PALATE. 



In the disease called scurvy, they tumefy and lose the firm- 

 ness of their texture : they acquire a livid color, and are much 

 disposed to hemorrhage. 



From the alveoli of the upper jaw, the lining membrane is 

 continued upon the palatine processes of the upper maxillary 

 and palate bones, or the roof of the mouth. 



The membrane of the palate is not quite so firm as that of 

 the gums, and is also less florid : it adheres firmly to the peri- 

 osteum, and thus is closely fixed to the bones. There is gene- 

 rally a ridge on its surface, immediately under the suture be- 

 tween the two upper maxillary bones ; and some transverse 

 ridges are also to be seen upon it. On the internal surface of 

 this membrane, are small glandular bodies, whose ducts open on 

 the surface of the palate. 



It is asserted, that this membrane has a limited degree of that 

 sensibility which is essential to the functions of tasting ; and 

 that if certain sapid substances are carefully applied to it, their 

 respective tastes will be perceived, although they have not been 

 in contact with the tongue. 



The membrane is continued from the bones above mentioned 

 to the soft palate, or velum pendulum palati, which is situated 

 immediately behind them. This soft palate may be considered 

 as a continuation of the partition between the nose and mouth ; 

 it is attached to the posterior edge of the palatine processes of 

 the ossa palati, and to the pterygoid processes of the sphenoidal 

 bone. Its interior structure is muscular. The upper surface is 

 covered by the membrane of the nose, the lower surface by the 

 membrane which lines the mouth. 



The muscles, which contribute to the composition of this 

 structure, are the circumflexi and the levatores palatii above, 

 and the constrictores isthmi faucium and palato-pharyngei below. 

 (See pages 318, 319.) Thus composed, the soft palate con- 

 stitutes the back part of the partition between the nose and 

 mouth. When viewed from before, with the mouth open, it 

 presents towards the tongue an arched surface, which continues 

 downwards on each side, until it comes nearly in contact with 

 the edges of that organ. On each of the lateral parts of this 



