147 



a I A c 



Papillae of the Tongue. 



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. 

 Magnified 2 diameters. 



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

 6. Line of basement membrane, d. Secondary papilla?, deprived of e, e, the epithelium, f. Hair-like 



illos. Magnified 25 diameters, g. Separated nucleated 



processes of epithelium capping 



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, show- 



'- -., but in all a coalescence of the particles 

 iiameters. 



ing varieties in the imbricated arrangement of the particles, 

 towards the point. 5. Incloses a soft hair. Magnified 160 di 



2. SAVOURS. 



Before proceeding to explain the physiology of gustation, it may be ne- 

 cessary to inquire briefly into the nature of bodies as connected with their 

 sapidity ; or, in other words, into savours, which are the cause of sapidity. 



The ancients were of opinion, that the cause of sapidity is a peculiar 

 principle, which, according to its combination with the constituents of 

 bodies, gives rise to various savours. This notion has been long aban- 

 doned ; and chiefly, because we observe no general or common charac- 

 ters amongst sapid bodies, which ought to be were they pervaded by the 

 same principle; and because bodies may be deprived of their sapidity 

 by subjecting them to appropriate processes. Many of our culinary 

 processes have been instituted for this purpose : the infusion of tea is 

 indebted for all its attractions to the power we possess of separating, by 

 boiling water, the savoury from the insipid portions of the plant. A 

 sapid principle must, therefore, be esteemed an integrant molecule of 

 a body ; not the same in all cases, but as heterogeneous in its nature 

 as the impressions made upon the organ of taste. 



