SMELLING, LIE A LING, ETC. 
97 
The tactile sensibility is called into play where 
nerves exist, and tactile hairs are found on different 
parts of the body, but it is only by the special senses, 
namely, by taste, smell, hearing, and sight, that this in- 
termediate organ between the nerve and the external 
■^orld is necessary. The first three have had attention 
in this chapter ; there still remains, therefore, the 
organ of sight, which we shall describe in the next 
chapter. 
H 
