THE NERVOUS SYSTEM 243 



In these movements the mind shares no part. And it is well 

 that this is so ; for, since the mind is largely occupied with 

 affairs external to the body, it acts irregularly, becomes 

 fatigued, and needs frequent rest. The spinal cord, on. the 

 contrary, is well fitted for the form of work on which depends 

 the growth and support of the body, as it acts uniformly, and 

 with a machine-like regularity. 



48. These operations are not accompanied by consciousness ; 

 for, as a general rule, the attention is only called to them when 

 they become disordered. Many a person does not know where 

 his stomach, is situated until he discovers its position by reason 

 of a feeling of distress within it, produced by giving that 

 organ improper work to perform. In this manner the higher 

 and nobler faculties of the mind are liberated from the simple 

 routine duties of the body, and we are thus left to direct the 

 attention, the reason, and the will to the accomplishment of 

 the great ends of our existence. If it were otherwise, we 

 could only find time to attend to our ordinary physical wants. 



49. The objects of the reflex activity of the cord are three- 

 fold. In the first place, it acts as the protector of man in his 

 unconscious moments. It is his unseen guardian, always ready 

 to act, never growing weary, and never requiring sleep. Nor 

 does its faithful action wholly cease with the cessation of life 

 in other parts. In the second place, it is the regulator of 

 numerous involuntary motions that are necessary to the nutri- 

 tion of the body. Here its actions are entirely independent 

 of the brain, and are performed in a secret and automatic 

 manner. And, thirdly, it acts as a substitute, and regulates 

 involuntary movements in the muscles usually under the influ- 

 ence of the will. It thus takes the place of the higher facul- 

 ties in performing habitual acts, and permits them to extend 

 their operations more and more beyond the body and its 

 material wants.^ 



50. The Functions of the Medulla Oblongata. The prolonga- 



48. Consciousness in these operations ? Physical wants ? 



49. How many objects may the reflex activity be said to have ? State the first. The 

 second. The third. 



60. How does the medulla oblongata resemble the cord ? 



