010 PLURALITY OF THE 



insensible, but the other end (next the ganglion,) 

 preserves an extreme sensibility." (Medico Chi- 

 rurgical Review, No. 62, p. 577.) Nor is it easy 

 to comprehend how impressions conveyed to the 

 brain through the external senses could be trans- 

 mitted to the voluntary muscles so as to direct 

 their movements, if wholly desitute of sensibility. 

 And although it is highly probable, that one set 

 of nerves may perform the office of conveying 

 information to the sensorium, and another set 

 that of transmitting it to the locomotive organs, 

 it is manifest that without sensation, there could 

 be no consciousness, memory, and volition, all of 

 which must therefore be modifications of one and 

 the same power, differing, however, according to 

 the various parts of the nervous system in which 

 it is exerted. 



For example, there is a striking difference be- 

 tween the sensations of feeling, hearing, seeing, 

 smelling, and tasting. Yet they are all excito mo- 

 tory, and may be resolved into the tactual agency 

 of material particles. The auditory nerves are 

 excited by the tactual influence of the atmos- 

 phere in a state of vibration, exerted on the tym- 

 panum, by which an endless diversity of words 

 of definite meaning are conveyed to the sensorium 

 commune, and the voluntary organs directed how 

 and when to move. Seeing is produced by the 

 tactual agency of light on the optic nerve, and 

 the visual impressions are transmitted to the lo- 



