THE NERVOUS SYSTEM 237 



The fact that these involuntary reflex acts are performed with 

 great precision, will explain why it is that accidents seldom 

 befall the somnambulist, or sleep-walker, although he often 

 ventures in the most perilous places. 



61. Walking, sitting, and other acts of daily life, become 

 automatic, or reflex, from habit; the mind is seldom directed 

 to them, but delegates their control to the medulla and spinal 

 cord. Thus a person in walking may traverse several miles 

 while absorbed in thought, or in argument with a companion, 

 and yet be conscious of scarcely one in a thousand of the acts 

 that have been necessary to carry his body from one point to 

 another. By this admirable and beautiful provision the mind 

 is released from the charge of the ordinary mechanical acts of 

 life, and may devote itself to the exercise of its nobler facul- 

 ties. And it is worthy of notice, that the more these faculties 

 are used, the more work does the. reflex function assume and 

 perform; and thus the employment of the one insures the 

 improvement of the other. (Read Notes 11 and 12.) 



11. Automatic Action of the Brain. "A large part of our mental 

 activity consists of this unconscious work of the brain. There are many 

 cases in which the mind has obviously worked more clearly and more 

 successfully in this automatic condition, when left entirely to itself, than 

 when we have been cudgeling our brains, so to speak, to get the solution. 

 An instance, well authenticated, is related of a college student ; he had 

 been attending a class in mathematics, and the professor said to his 

 students one day : ' A question, of great difficulty has been referred to me 

 by a banker a very complicated question of accounts, which they have 

 not themselves been able to bring to a satisfactory issue, and they have 

 asked my assistance. I have been trying, and I cannot resolve it. I 

 have covered whole sheets of paper with calculations, and have not been 

 able to make it out. Will you try ? ' He gave it to them as a sort of 

 problem, and said he would be extremely obliged to any one who would 

 bring him the solution by a certain day. This gentleman tried it over and 

 over again ; he covered many slates with figures, but did not succeed. 

 He was ' put on his mettle,' and determined to achieve the result. But 

 he went to bed on the night before the solution was to be given in with- 

 out having succeeded. In the morning, when he went to his desk, he 

 found the whole problem worked out and in his own hand. He had 

 risen in the night and unconsciously worked it out correctly, as the 



61. What is said of walking and other acts in connection with the office performed by 

 the ined ulla and spinal cord ? 



