474 STUDIES IN ADVANCED PHYSIOLOGY. 



all that they are mere mental inferences, but he seems ac- 

 tually to feel the sensation in his foot. 



What is true of the sensation of touch might be equally 

 applicable to all the other senses. That the reference of 

 our sensations is a mere matter of inference may be proved 

 by the fact that the "seeing of stars" (which results from 

 a blow on the head) is projected through the eyes into the 

 external world. A blow on the ulnar nerve at the elbow 

 (the crazy-bone) results in a sensation which is referred not 

 to the elbow where it arose, but to the fingers and hand. 

 This mistake occurs from the fact that the brain has been 

 accustomed to believing that all sensations carried by the 

 ulnar nerve come from the hand. The truth of this belief 

 has been established to the brain over and over again, and 

 so when this impulse reaches the brain along the ulnar 

 nerve it is without question referred to the same place, and 

 this reference by the brain is so distinct and real that it is 

 really hard to believe that the pain is not actually in the 

 fingers. 



That the reference of our sensations to the external 

 world is a matter of acquirement is proved further by the 

 possibility of educating the brain in this matter. Blind 

 people who rely much more upon their sense of touch be- 

 come remarkably proficient in localizing touches, even to 

 the extent of being able to read raised print rapidly and ac- 

 curately with their finger tips. It is also stated that per- 

 sons who had been blind and whose eyesight was suddenly 

 restored, by some kind of operation probably, did not at 

 first see objects at a distance, but referred all of their 

 visual sensations to the eye itself. Such persons felt a 

 distant tree, not as an object of the external world, but as 

 a peculiar and new sensation in the eyeball. 



THE RELATION BETWEEN NEUROSIS AND PSYCHOSIS. 



It was just pointed out that there is the relation of cause 

 and effect between the nervous excitation in the end organ 

 and the mental change in the brain. There is a relation of 



