196 SENSORIAL FUNCTIONS. 



others the sharp cry of a bat ; and he refers to one who 

 was insensible to the note of the sparrow. 



ORGANS OF SMELL. 



609. From nearly all bodies there escape certain parti- 

 cles, 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 grat 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. 



610. We cannot describe an odor, except to persons 

 who have themselves smelled that which we intend to 

 describe, 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 com- 

 pare odors, so far as to specify what is agreeable and 

 what not. 



611. It is exceedingly difficult for us to conceive how 

 matter, so rare and minute as must be the particles of 

 some odoriferous bodies, can excite any sensation on the 

 animal organs. Thus a single grain of musk will scent 

 an apartment for years, and still not loose the least ap- 

 preciable 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. Wol- 

 laston observe with respect to the sense of hearing? What excites the 

 sense of smell? What bodies are inodorous? What is said of the de- 

 scription of odors ? 



