402 



ON SENSATION, AND THE ORGANS OF THE SENSES. 



c. The Simple papillae which occur in an isolated manner, with those which are aggre- 

 gated in the Circum valla te and Fungiform bodies, doubtless minister to the sense of Taste; 

 but there seems much reason to coincide in the opinion of Messrs. Todd and Bowman, with 

 regard to the different office of the Filiform papillse. " The comparative thickness of their 



[Fig. 170. 



A. Vertical section near the middle of the dorsal surface of the tongue : a, a. Fungiform papillae. 6. 

 Filiform papillae, with their hair-like processes, c. Similar ones deprived of their epithelium. Magni- 

 fied 2 diameters. 



B. Filiform compound papillae : a. Artery, v. Vein. c. Capillary loops of the secondary papilla 1 . 

 b. Line of basement membrane, d. Secondary papillae, deprived of e, e, the epithelium. /. Hair-like 

 processes of epithelium capping the simple papilla?. Magnified 25 diameters, g. Separated nucleated 

 particles of epithelium, magnified 300 diameters. 



1, 2. Hairs found on the surface of the tongue. 3, 4, 5. Ends of hair-like epithelial processes, showing 

 varieties in the imbricated arrangement of the particles, but inall a coalescence of the particles towards 

 the point. 5> encloses a soft hair. Magnified 160 diameters.] 



protective covering, the stiffness and brush-like arrangement of their filamentary productions, 

 their greater development in that portion of the dorsum of the tongue which is chiefly em- 

 ployed in the movements of mastication, all evince the subservience of these papilla? to the 

 latter function, rather than to that of taste; and it is evident that their isolation and partial 

 mobility on one another, must render the delicate touch with which they are endowed, more 

 available in directing the muscular actions of the organ. The almost manual dexterity of the 

 organ, in dealing with minute particles of food, is probably provided for, as far as sensibility 

 conduces to it, in the structure and arrangement of these papillre." It may be added, that 

 the filiform papillre of Man seem to be the rudimentary forms of those homy epithelial pro- 

 cesses, which acquire so great a development in the tongues of the Carnivora, and which are 

 of such importance in the abrasion of their food. 



