CHAPTER V. 



Motion. Effort. Locomotion; standing, walking, running, jumping, 

 swimming. 



Motion. Physiologists remark several varieties of motion 

 which may be grouped in two voluntary and involuntary 

 movements. Among the involuntary movements, which ars 

 also called automatic, some result from the impression pro- 

 duced by an idea, a passion, or a scene, gay or sad, or by a 

 movement identical with that which is produced. Such art, 

 laughing, and the motions of the face expressing sadness, 

 anger, fear, and other moral or physical impressions; trem> 

 bling of the limbs in consequence of deep emotion, yawning, 

 and so forth. Others proceed from the excitement of ths, 

 sensitive nerves, such as sneezing, coughing, winking, chat- 

 tering of the teeth, or shivering after a cold bath. 



In certain cases, in fact, impressions transmitted from th& 

 organs to the brain, either directly by the nerves of sensa- 

 tion or indirectly by the spinal cord, without any sensation 

 taking place, or what amounts to the same thing, without 

 our being conscious of any, occasion an excitement which is 

 transmitted to the motor-nerves, and causes movements in 

 which the will has no part. These movements are generally 

 executed by the muscles of organic life, which are not 

 under the control of the will ; but they can also be made by 

 those which are under its control. These are called reflex 

 movements. Some of them are undoubtedly automatic; as 

 for the others, it has not been demonstrated that a sensation 

 and an act of the will do not precede the muscular contrac- 

 tion. Thus sneezing and coughing are independent of the 



