174 THE NERVOUS SYSTEM. 



56. All these mental acts, and many others, are devel- 

 oped through the action of the brain ; not that the brain 

 and the mind are the same, or that the brain secretes 

 memory, imagination, or the ideas of truth and justice, as 

 the stomach secretes the gastric juice. But rather, as the 

 nerve of the eye, stimulated by the subtile waves of light, 

 occasions the notion of color, so the brain, called into 

 action by the mysterious influences of the immaterial soul, 

 gives rise to all the intellectual, emotional, and voluntary 

 activities of mankind. 



57. The cerebrum, according to our present knowledge 

 of it, must be regarded as a single organ, which produces 

 different results, according as it is acted upon by the im- 

 material mind in different ways. Recent investigations, 

 however, seem to prove that the faculty of language is de- 

 pendent upon a small part of the left hemisphere of the 

 cerebrum, near the temple. At least, in almost every 

 instance where this part is diseased, the patient can no 

 longer express himself in speech and writing. 



58. The Reflex Action of the Brain. The reflex 

 function of the organs within the skull is very active and 

 important. Like that of the cord, it protects the body by 

 involuntary movements, it regulates the so-called vegeta- 

 tive acts, and it takes the place of the will in controlling 

 the voluntary muscles, when the attention is turned in 

 other directions. The reflex power of the medulla governs 

 the acts of respiration, which are absolutely and continu- 

 ously essential to life. Respiration is, as we have seen, 

 partly under the influence of the will; but this is due in 

 part to the fact that respiration is indirectly concerned in 

 one of the animal functions, that of speech. 



59. Reflex action also occasions coughing and sneezing, 



56. Are the brain and the mina identical? 



57. What do we know of the cerebrum and its powers ? 



58. The reflex function of the organs within the skull? The reflex power oi 

 the medulla ? Respiration ? 



59. What else does reflex action occasion ? Winking? Other examples ? 



