298 APPLIED PHYSIOLOGY 



others. Knowledge gained only by long and patient 

 research of wise men is imparted to children in a few 

 moments, while an animal can impart knowledge only in 

 a limited degree. 



539. Speech in animals. All animals have a variety of natural 

 cries. Monkeys have a dozen separate cries which are similar in all 

 species. A hen has at least five different cries to express as many 

 different ideas. Parrots and crows have been taught to speak a few 

 words, but they do it just as the mocking bird or brown thrush imitates 

 any sound which it hears. Speech belongs to man alone. 



540. Of what speech consists. Speech is one of the 

 highest and most complicated of mental processes. It is 

 not a natural gift, but must always be learned at first. 

 A child first hears a word spoken. He records it in the 

 temporal regions of the brain, and learns to recall certain 

 sensory and motor memories when he hears the word. 

 By the time he is a year and a half old his motor region 

 begins to form the word when he thinks of the memory. 

 At the age of six or eight he begins to recognize the printed 

 word with his sight region, and finally he learns to write 

 the word with his motor region. Thus nearly every region 

 in the brain takes part in some form of speech. 



541. Center for spoken words. The muscles of the 

 mouth can be moved by the cells of the face center in the 

 motor region, but their movements in speech are so precise 

 and complicated that a center is especially provided to pro- 

 duce their movements in talking. It is situated just below 

 and in front of the motor area, but is usually upon only 

 one side. When this center is disturbed, a person cannot 

 talk, although he understands spoken and written speech, 

 and has control of his lips and tongue in doing other things. 



542. Disturbance of the speech centers. There are cases 

 in which the word-seeing center is disturbed so that a person can 



