698 



PHYSIOLOGY. 



clinical experience, Dr. Mills has located the motor centers for man 

 mainly in the ascending frontal and the paracentral convolutions. 

 The posterior central (ascending parietal) is for tactile sensation. 

 Muscle-sensibility is in the superior and inferior parietal convolu- 

 tions. Stereognostic perception is located in the superior parietal. 

 On the mesial surface of the hemisphere he locates stereognostic per- 

 ception in the precuneus. The center of speech is in the posterior 

 part of inferior left frontal gyrus. 



CONCRETE CONCEPT 



Fig. 281. Areas and Centers of the Lateral Aspect of the Human 

 Hemicerebrum. ( MILLS . ) 



In stereognosis the form of an object is recognized by tactile 

 sensibility, although the eyes are closed. The cortical motor center 

 for writing is seated in the base of the left frontal gyrus. There is 

 clinical evidence to substantiate the fact that disease of the left angu- 

 lar gyrus may cause agraphia; for it must be remembered that, in 

 order to write, it is absolutely essential to call to the mind memories 

 of the words previously written. The center of taste and smell is in 

 the uncus. 



Auditory Center. This center is seated in the first temporal 

 convolution and in part of the second. Complete deafness is not 

 produced in man when there is total destruction of one center, which 

 proves that there is only a partial decussation of the auditory path- 



