THE CEREBRUM. 507 



growth of tumors, softening, etc., is followed by paralysis of the 

 muscles. Electric stimulation of the human brain for the purpose of 

 localizing obscure irritative lesions prior to surgical procedures on 

 the brain gives rise to the same convulsive movements. 



The Sensor Areas. The sensor areas occupy regions corre- 

 sponding in a general way with those of the monkey brain. 



The cutaneous and muscle sense areas have been assigned to the 

 post-central, a portion of the superior and inferior parietal convolu- 

 tions on the lateral aspect, and to portions of the frontal convolution 

 and of the gyrus fornicatus on the mesial aspect. It is also probable 

 that the tactile (cutaneous) area may be assigned, though in less 



FIG. 227. THE AREAS AND CENTERS OF THE MESIAL ASPECT OF THE 

 HUMAN HEMI-CEREBRUM. (C. K. Mills.) 



degree, to the pre-central convolution, the general motor area. This 

 is in accordance with the embryologic investigations of Flechsig, who 

 concludes that the entire Rolandic region is to be regarded as sensor 

 as well as motor in function, and names it the area of body feelings, 

 or the somesthetic area. 



The clinical and postmortem evidence as to the extent of the 

 area of tactile sensibility and its coincidence with the motor area is 

 somewhat contradictory, and in some respects apparently in opposi- 

 tion to the view of Flechsig. Thus, Dr. C. K. Mills, whose skill in 

 interpreting the phenomena of disease is well known, states in this con- 

 nection in his work on nervous diseases that " innumerable cases have 

 been reported of lesions of the motor cortex without the slightest 



