BRAIN 



BRAKE 



contains many folds or convolutions, which 

 greatly increase the surface of the gray matter. 

 It is estimated that the surface of the cerebrum 

 is equal to that of the human trunk, but by 

 means of these folds it is compacted into a 

 small space. 



The cerebrum is the controlling organ of the 

 body, the seat of mental activities and volun- 

 tary action. It also contains centers of sight, 

 hearing, taste, touch and smell. It is divided 

 into numerous centers, each of which controls 

 certain movements, or functions. Injury to one 

 of these centers results in the loss of the func- 

 tion over which it presides. If the visual cen- 

 ters are injured blindness follows; if the audi- 

 tory centers are affected one becomes deaf. 

 Paralysis of any part of the body is usually 

 caused by the formation of a blood clot over 

 the brain center controlling the motor, or 

 motion, nerves that extend to that part of 

 the body. While many centers have been 

 located, there are many more whose locations 

 are not yet known. In this respect the brain 

 is like an unknown country, of which no com- 

 plete maps have been made. 



The Cerebellum. The cerebellum is situated 

 in the back of the head, below the cerebrum. 

 It is partially divided into hemispheres, and 

 each hemisphere is connected with the cere- 

 brum by three sets of nerve fibers. The gray 

 and white matter intermingle in the cerebellum 

 more fully than in the cerebrum. The white 

 matter consists of nerve fibers which unite into 

 a system of nerves that extend through the 

 spinal cord to all parts of the body. The chief 

 function of the cerebellum seems to be to har- 

 monize those muscular movements necessary 

 to maintain the body in an upright position 

 when standing, walking and running. If this 

 part of the brain is injured one staggers like 

 a drunken man when one attempts to walk. 



The Pons. The pons is a passage way for 

 nerves from various parts of the nervous sys- 

 tem. It seems to be used chiefly as a means 

 of communication, but it is supposed to be the 

 seat of other functions not yet understood. 



The Medulla Oblongata. We have already 

 remarked that the medulla, at the base of the 

 brain, is really a part of the spinal cord. The 

 nerve fibers passing from the brain to the spinal 

 cord cross in the medulla to the other side, 

 so that the nerve centers in the brain control 

 the movements on the opposite side of the 

 body; paralysis of the motor nerves in the 

 right side of 'the brain results in paralysis of 

 the left side of the body. The motor centers 



of the right hemisphere of the cerebrum con- 

 trol the movements of the left hand and leg, 

 and those of the left hemisphere control the 

 right arm and leg. 



The first function of the medulla is to trans- 

 mit the nerve impulse to and from the brain. 

 Its second function is reflex action, that is, send- 

 ing a motor impulse to any part of the body, 

 before the sensation resulting in that impulse 

 reaches the brain. The third function of the 

 medulla is to preside over those movements 

 necessary to the maintenance of life which 

 are carried on without the action of the will, 

 such as respiration, circulation and digestion. 

 Because of this function the medulla is some- 

 times called the "vital knot." 



Health of the Brain. The brain, like the 

 muscles, is strengthened by use and fatigued 

 by over-exertion. Sleep* is merely a resting 

 time of the brain and nerves, and plenty of 

 sleep is essential to a healthful nervous system. 

 Fresh air, nourishing food and bodily exercise 

 are also necessary to clear thinking and vigor- 

 ous mental action, which can come only from a 

 healthy brain. Narcotics, alcoholic beverages 

 and drugs all work more or less injury to the 

 brain and should be avoided. WJV.E. 



Related Subjects. In connection with the 

 above article, the following topics will be found 

 interesting and helpful : 

 Aphasia Nerves 



Apoplexy Nervous System 



Epilepsy Reflex Action 



Meningitis Spinal Cord 



BRAINERD, MINN., the county seat of 

 Crow Wing County. It is on the east bank of 

 the Mississippi River, which is dammed and 

 provides water power for the city's mills and 

 factories. It is on the Northern Pacific and 

 the Minnesota & International Falls railways, 

 138 miles northwest of Saint Paul and 118 miles 

 southwest of Duluth. Brainerd is a shipping 

 center for grain, iron ore and lumber, and has 

 large railway shops. It was chartered as a 

 city in 1883. Population in 1910, 8,526. 



BRAKE, or BRACKEN, a species of fern 

 very common in North America, Europe and 

 Asia, often covering large areas of hillside and 

 untilled ground. It has a black, creeping root- 

 stock, from which fronds grow often to the 

 height of several feet and divide into three 

 branches. As the plants do not fall when the 

 frost kills the tops, "they form a good cover 

 for small game throughout the year. The 

 rootstbck is bitter, but has been eaten in times 

 of famine. It has also been used in place of 



