280 STUDIES IN PHYSIOLOGY 



chest. I then sneeze, and thus get rid of the pepper. 

 Coughing, winking, blushing, the flow of saliva at the sight 

 of savory food these are but a few of the reflex activities 

 carried on by the brain. 



Conscious Activities. As long as we keep awake, countless 

 nerve impulses keep pouring into our brains. When the 

 cells of the gray matter receive these impressions, we usu- 

 ally become conscious that we are seeing, smelling, hearing, 

 tasting, or feeling. These sensations are more or less last- 

 ing, too, for we can recall distinctly the appearance of ob- 

 jects that we saw yesterday, or even years ago, and we can 

 hear again, as it were, the sounds we have heard in the 

 past. In some unknown way these impressions are stored 

 away in the protoplasm of our brain, and constitute our 

 memory. 



Another power of which we are conscious is the ability 

 to direct the movements of the body. I can rise from my 

 seat, walk about, talk, or change the expression of my face 

 as I will. Or, to return to the experience of burning my 

 finger, I might by the exercise of my will power prevent 

 the withdrawal of my hand from the hot stove, and if I 

 had enough will power I might keep it there until it was 

 scorched. 



Localization of Functions in the Brain. The facts just 

 stated have long been known, but only in recent years 

 have we discovered that certain functions are located in 

 definite parts of the brain. The nerves that come from 

 the eyes, after crossing on the ventral surface of the brain, 

 pass through the midbrain, and finally end in the cells 

 of the occipital convolutions of the forebrain. Thus, odd 

 as it may seem, we all see crosswise and in the back 

 part of our heads ! The sense of hearing is located 

 in the temporal convolutions below the fissure of Sylvius. 

 Smell, taste, and touch have not as yet been satisfactorily 

 localized. 



In the convolutions on both sides of the -fissure of 



