448 



SPECIAL HISTOLOGY. 



substance by means of a dense layer of connective tissue (see above 

 181) ; it has itself a dense and solid appearance, though in conse- 

 quence of the presence of a considerable quantity of elastic tissue, of 

 common fat cells of 0'016-0'024 of a line, and of its abundant vascular 

 supply, it is tolerably elastic. 



The papillce filiformes or conicce (Fig. 173), are conical processes of 

 mucous membrane beset either at their extremities only, or over their 

 whole surface, with a certain number (5-20) of smaller secondary 

 papillce of 0-1-0-14 of a line in length. The whole is invested with a 



Fig. 173. 



Fig. 174. 



thick epithelial coat drawn out at its extremity into a number of long, 

 thin (0-01-0-02 of a line), fine and often subdivided, processes (Fig. 173,/), 



FIG. 173. Two papilla filiformes of man, one with its epithelium magnified 35 diameters. 

 After Todd and Bowman: p, the papilla themselves; a, v, arterial and venous vessels of 

 papilla, together with the capillary loops, which, however, ought to enter the secondary 

 papilla. 



FiG. 174. Jl, papilla fungiformis, with its secondary or simple papillae, p, on one side still 

 covered with epithelium, e ; magnified 30 diameters. JB, the same, with only the outlines 

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

 papilla? ; , capillaries in the simple papillae of the mucous membrane at the base of the p. 

 fungiformis ; magnified 18 diameters. After Todd and Bowman. 



