THE CEREBRUM. 



553 



tion from below upward is similar to that observed in the monkey. One 

 peculiarity, however, was the location of the area for conjugate deviation of 

 the eyeballs to the opposite side. This is situated far forward in the middle 

 and inferior frontal convolutions, and separated from the areas in the pre- 

 central convolution by a region apparently inexcitable. These facts are of 

 great interest and value in the assignment of the motor areas in the cortex 

 of the human brain, as in its development and configuration the chimpanzee 

 brain more closely resembles the human brain than does the monkey's. 

 The Localization of Sensor and Motor Areas in the Human Brain. 

 The observation of clinical symptoms and their interpretation by post-mortem 

 findings, the phenomena observed during surgical procedures, and the results 



FIG. 253. THE AREAS AND CENTERS OF THE MESIAL ASPECT OF THE HUMAN HEMICEREBRUM. 



(C. K. Mills.) 



of embryologic investigations, point to the conclusion that corresponding 

 areas both for sensations and movements exist in the cerebral cortex of the 

 human brain, though it is probable that their locations do not in all respects 

 coincide with those characteristic of the monkey or even the ape brain. In 

 the following diagrams (Figs. 252 and 253), the sensor and motor areas are 

 at least provisionally located, in accordance with recent observations. They 

 are represented as limited or bounded by a serrated line to indicate, as 

 suggested by Mills, that they are not sharply delimited, but that they inter- 

 fuse or interdigitate with surrounding regions. 



The Sensor Areas. The sensor areas occupy regions corresponding 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 super- and sub-parietal convolutions on the lateral 

 aspect, and to portions of the frontal convolution and of the callosal convolu- 

 tion on the mesial aspect. It is also probable that the tactile (cutaneous) 

 area may be assigned, though in less degree, to the pre-central convolution, 

 the general motor area. This is in accordance with the embryologic investi- 



