200 SENSORIAL FUNCTIONS. 



the chirp of a grass-hopper ; others the sharp cry of a 

 bat ; and he refers to one who was insensible to the note 

 of the sparrow. 



ORGANS OF SMELL. 



From nearly all bodies there escapes certain particles, 

 which being carried along by the air, are taken into the 

 nostrils where they excite the sensation which we call 

 odor, or smell. 



All bodies, the particles of which are fixed, are called 

 inodorous, that is, they do not excite the sensation of 

 smell. 



Some bodies, it is well known, fill the air to great dis- 

 tances with their odoriferous particles, while in others, 

 under ordinary circumstances there is no appreciable 

 smell. 



Every odoriferous body excites a sensation peculiar 

 to itself, and hence has a peculiar odor. 



We cannot describe an odor, except to persons who 

 have themselves smelled that which we intend to de- 

 scribe ; or something with which we can compare it. 

 Thus, no one could have the least idea of the smell of 

 camphor, or musk, who had not experienced it. The 

 terms aromatic, or sweet, and rancid, or fetid, are gene- 

 ral terms intended to include odors which are pleasant 

 or disagreeable, and in these respects we are able to 

 compare odors, so far as to specify what is agreeable 

 and what not. 



It is exceedingly difficult for us to conceive how mat- 

 ter, so rare, and minute, as must be the particles of some 

 odoriferous bodies, can excite any sensation on the ani- 

 mal organs. Thus a single grain of musk will scent an 

 apartment for years, and still not loose the least appre- 

 ciable part of its weight, though tried by the nicest 

 scales , and it is said, if a little of this drug be put into a 



How is it proved that the appreciation of harmony is owing to effect 

 on the brain, and not merely on the ear? What peculiarities did Dr. 

 Wollaston observe with respect to the sense of hearing 7 What excites 

 the sense of smell 1 What bodies are inodorous'? "What is said of the 

 description of odors 1 



