118 PHYSIOLOGY. 



organ. Thus it is not unusual to see persons who have lost 

 a limb complaining of pain, or some other sensation in the 

 part which has been cut off, and thus they often imagine 

 that the limb is entire. Here the sensation existed only in 

 the mind ; in the same manner ghosts, hobgoblins, and other 

 strange sights are seen ; but the sensation is only in the 

 brain. 



23. That the brain is the real seat of all our sensations 

 may be proved from other facts. If a person receives a 

 blow upon the head so as to stun him, or deprive him of 

 consciousness, though the organs of sensation and the senses 

 are wholly uninjured, he takes no notice of any thing ; he 

 receives no sensations from any of his senses ; in fact, he is 

 said to be insensible. The same thing happens if he become 

 stupid by the use of alcohol, opium, or any narcotic. If the 

 quantity is not enough to produce entire torpor of the brain, 

 his senses are impaired, his reason is gone ; he is in short a 

 voluntary mad-man. 



24. (During sleep, the senses are said to be locked up. 

 But though the eye is closed, the ear is open ; the nerves in 

 which the sense of touch resides, are still spread out upon 

 the skin, but yet no impressions are felt ; no sensations are 

 excited ; no notice is taken. The reason is, the brain is in 

 a state of repose ; the ship does not obey the rudder, be- 

 cause the man at the helm is asleep ; the steamboat is not in 

 motion, for although she has furnace, boilors, condensers, 

 paddle-wheels, and all, yet the steam is not up ; so in sleep, 

 the organs of sense are all sound, yet the brain, the rudder 

 of the mind, the moving agent of the animal machine, is 

 dormant ; the messages of its servants, the organs of sense, 

 are neither received, noticed, nor acted upon. 



25. There is another curious circumstance connected 

 with the brain ; /it may be so much employed in thought, 

 or deep meditation, as not to notice the impressions made 

 on the senses^ In this case, a person is said to be absent- 

 minded. Though the eyes and ears are open, the brain is 



