THE TONGUE. 447 



when they are well developed, of a central round papilla, flattened 

 at the end, having a diameter of J-l line, and -J or even f of a 

 line high ; and of a lower uniform wall J-J of a line broad, which 

 closely surrounds the papilla, particularly at its base. These impillce, 

 however, vary much in number, size, and position, and occasionally pass 

 into the fungiform kind ; which is especially true of the posterior ones 

 lying in the foramen ccecum, or Morgagnii. The papillae anterior to 

 the circumvalldlce, are arranged in more or less regular rows, which in 

 general run parallel to the latter, and pass, upon the border of the 

 tongue, into laminated, sometimes not even notched folds, which can no 

 longer be considered as papillce. The papillce fungiformes or clavatce 

 are 0-3-0-8 of a line in length, 0-2-0-5 of a line in breadth ; they have 

 smooth surfaces and, during life, are readily recognised by their red 

 color ; they abound particularly upon the anterior half of the tongue, 

 scattered over its surface at tolerably regular intervals of -| 1 line and 

 more ; and at the point, indeed, they are often so thickly crowded as to 

 be in contact ; they are not absent, however, upon the posterior half, as 

 far back as the papillce circumvallatce. The papillce filiform es or conicce 

 are J-l J lines in length, and 0-1-0-2 of a line in breadth, and rendered 

 very obvious by their number and whitish color ; they occupy, in close 

 contact with one another, the intervals between the fungiform kind, and 

 invariably appear most densely crowded and best developed, with brush- 

 like ends, in the concave side of the Y of the circumvallate papillce, and 

 in the middle line of the centre of the tongue. Towards the edges and 

 the point, the papillce themselves, as well as their processes, become 

 shorter, and to some extent more scanty, so that they gradually pass 

 into the laminct to which we have referred, and also in many respects 

 approximate the fungiform papillce ; from which, in fact, so far as the 

 structure of their surface is concerned, they become hardly distinguish- 

 able. 



Besides these papillce which project freely, there may also be observed 

 over the whole gustatory region of the tongue, smaller ones completely 

 buried in the epithelium, which are perfectly similar to those of the non- 

 gustatory parts of the organ. 



With respect to the minuter structure of the mucous membrane of the 

 tongue, that part of it which presents no projecting papillce, differs in 

 no respect from the mucous membrane of the oral cavity, and possesses, 

 in fact, a laminated pavement epithelium of 0-045 of a line in thickness at 

 the root of the tongue, of 0-06-0-1 of a line on the lower surface of its 

 apex, with simple small imbedded. papillae of 0-024-0-05 of a line in length, 

 0-004-0-02 of a line in breadth, which are not absent even upon the ante- 

 rior surface of the epiglottis, and between it and the papillce circumvallatce. 

 In the proper gustatory region of the tongue the submucous tissue is 

 wholly absent, the mucous membrane being united with the muscular 



