FEELING AND WILLING. 1 99 



heart, and the drawing of every breath, and the secre- 

 tion of digestive fluids in the proper amount at the 

 proper moment, and the blood-flow through each organ 

 according to its needs at that time, and so forth, our 

 minds would have time for nothing else. All this daily 

 routine is looked after by nerve-centres which act in- 

 voluntarily, and leave the mind free for other duties. 



10. Feeling and Willing. The spinal cord, the medulla 

 oblongata, and the cerebellum direct unconscious and 

 involuntary movements. The cerebrum guides some 

 such movements, but it does more: it is connected in 

 some way with feeling and willing. No part of the body 

 which is not joined by at least one nerve-fibre to the 

 cerebrum, has feeling ; and no muscle not joined to it in 

 like way, can be controlled by the will. 



For example, the nerve-fibres coming from the leg all 

 unite, above the hip, into three or four large cords, which 

 enter the spinal cord near its lower end. If all the 

 nerves be cut at the ankle, the foot loses feeling, and all 

 the muscles in it are paralyzed; that is to say, cannot be 

 made to contract by their owner when he wishes. If 

 only some of the nerve-fibres going to the foot be cut, 

 then only that part of it to which the divided fibres went, 

 loses feeling and has its muscles paralyzed. If all the 

 nerves be cut at the knee, instead of the ankle, then both 

 the foot and the lower part of the leg become insensible 

 and paralyzed. If they be divided or crushed at the hip- 

 joint, then the thigh also is put in the same condition. 



10. What centres direct most involuntary movements? What part 

 of the body is especially concerned in feeling and willing? What is 

 said of muscles and other parts not joined to the cerebrum by a nerve- 

 fibre ? Illustrate from the results of injuries to the nerves of the leg 

 at the ankle. The knee. The hip. What results when the spinal 



