THE CEREBRUM AND HUMAN DEVELOPMENT 149 



guage would have been opened in the right hemisphere also. 

 When the left hemisphere was forced to provide the 

 nervous government for the skilled hand the mechanisms 

 related to language had likewise to be furnished by that 

 side of the cerebrum. Time was lost when the original 

 foundations in the right hemisphere were abandoned in 

 favor of new ones which had to be constructed in the left. 



When the command of spoken language suffers it is 

 commonly observed that the subject shows some loss of 

 general intelligence and of the power to read and write. 

 But there have been many cases in which one or another 

 of these specific accomplishments has been more or less 

 completely abolished without much impairment of the 

 remaining functions. So we read of the loss of the ability 

 to write consequent on damage to a region just above the 

 speech center as usually indicated. The writing center, if 

 it has as definite an existence in space as has been claimed 

 for it, is near the motor area for the trained hand and may 

 be thought of as a special extension of that area. 



Sometimes the power to read is lost, though the victim 

 is not blind. The letters are seen clearly enough, but do 

 not rouse the associations which they had previously 

 acquired. It is a set-back in education a return to the 

 condition of the child whose eyes are keen, but who has 

 not learned to read. Since reading is a specially devel- 

 oped function of -vision, it is not strange that a state like 

 this has often attended injury to the hinder part of the 

 cerebrum on the left side and outside the general visual 

 region. Destructive processes near but not covering the 

 supposed auditory area of the left temporal lobe have 

 sometimes led to a condition described as "word deafness," 

 sounds being distinctly heard, but words no longer serving 

 to convey their old meanings. The experience is probably 

 just that of listening to an unfamiliar foreign language. 



The integral existence of four centers for language, 

 that is, for vocal speech, writing, reading, and the transla- 

 tion of words spoken by others, is not so confidently 

 maintained as it was a few years ago. If the true con- 



