THE TONGUE. 



17 



nective tissue, and a very considerable number of elastic fibrils, 

 which as 10—20 wavy threads of 0004 — 0*0008'", penetrate 

 even to the points of the simple papillae, and give to the whole 

 cone and its processes a certain solidity and firmness which are 

 not possessed by the simple papillae of the mucous membrane. 

 A minute artery ramifies in each filiform papilla, in such a 

 manner, that every simple papilla contains a capillary loop of 

 0*004 — 0-005"', from whose reunion a small vein arises. It is 

 difficult to discover the nerves, on account of the abundant elastic 

 tissue; and in many papillae they may be sought in vain. In 

 the majority, however, at least at the base of the papillae, they 

 are quite distinct, in the form of one or two delicate trunks, 

 with 5—10, dark edged primitive fibrils of 0-002 — 0-003'", 

 which gradually become finer as they run towards the point. I 

 have been unable to make out with certainty how the nerves 



Fig. 174. 



terminate, yet everything appeared 

 to indicate the existence of loops, 

 not, however, in the simple papillae, 

 but at their base. In animals these 

 loops are more distinct, as for ex- 

 ample, in the Calf, where every fili- 

 form papilla receives 10 — 12 primi- 

 tive fibrils, of 0-002— 0-003'", which 

 diminish to O'OOl'", and do not 

 enter the simple papillae. 



The papilla fungiformes consist 

 of a clavate primary papilla, whose 

 entire surface is beset with closely 

 placed, conical, secondary papillae, t 

 0'1— -0'12'" in length, and invested 

 with a simple epithelium, such as 

 is met with elsewhere in the 

 oral cavity, without filiform pro- 

 cesses, or any very horny cells, and which, measured from 

 their points, has a thickness of 004 — 0*05'". The primary 



Fig. 174. A, papilla fungiformis, with its secondary or simple papillae,/?, on one 

 side still covered with epithelium, e, x 35. B, the same, with only the outlines of the 

 epithelium, e, and the vessels; a, artery; v, vein; d, capillary loops of the simple 

 papillae ; e, capillaries in the simple papillae of the mucous membrane at the base of 

 the p. fungiformis; x 18 diam. After Todd and Bowman. 



ir. 2 



