500 THE SOLIDS. 



the mucous membrane of the tongue ; and it is but natural 

 to suppose that the principal portion of this is destined 

 to the discharge of the function for which it has so evidently 

 been designed. 



The filamentary papillae fcave generally been considered 

 to be ill adapted to the reception of gustatory impressions in 

 consequence of the character of the epithelial processes in 

 connection with them ; and it has been supposed that they 

 are to be regarded as tactile rather than gustatory organs. 

 This opinion has, however, been entertained in the absence 

 of a full knowledge of the real form and structure of these 

 papillae, as already shown. 



It has occurred to me that these filamentary processes act 

 as absorbents of the nutrient juices, and that collectively they 

 constitute an absorbent surface of considerable power, con- 

 veying directly to the papilla those fluids, and keeping them 

 in contact with the papillae for a time, thus prolonging the 

 duration of the gustatory impression. This idea would appear 

 to gather confirmation from the fact that it is in these fila- 

 mentary epithelial prolongations that the variable coating 

 known as the fur of the tongue has its seat. 



SMELL. 

 Structure of the Mucous Membrane of the Nose. 



The anatomical characters of the mucous membrane of the 

 nose differ in different regions ; for a short distance within 

 the anterior nares, the mucous membrane presents many of 

 the characters of the skin, it being divisible into chorion, 

 papillary structure, and epidermis ; the papillae resemble in 

 every respect those of the sense of touch, and the epidermis 

 consists of flattened epithelial scales analogous to those of the 

 same structure in the skin. This, the commencement of the 

 nasal mucous membrane, may be called the tactile region of 

 the nose, and it is abundantly furnished with hairs, which 

 guard the entrances of the nares, and the roots of which are 



