630 



THE HUMAN BODY. 



that must be a very uncertain deduction. Also, the optic 

 tract of each side has through the anterior corpus quadri- 

 geminum and some other gray masses a close connection with 

 the cortex of the occipital lobe. Probably, therefore, that 

 region has some close 'connection with vision. There is also 

 some evidence that the angular gyrus (an, Fig. 179) has con- 

 nection with sight. 



The sense of smell has been supposed especially connected 

 with the uncinate gyrus of median side of the temporal lobe 

 (un, Fig. 180), and the sense of taste with a neighboring 



Ro 



FIG. 180. Diagram of inner surface of left cerebral hemisphere to illustrate 

 cerebral localization. Sq, fissure of Sylvius; Ro, fissure of Rolando; Fr, frontal 

 lobe; Of, occipital lobe: Te, temporal Jobe; C.cZ, corpus callosum; ZZ7, third ven- 

 tricle. Compare with Fig. 179. 



area, but the evidence is unsatisfactory; and the same may be 

 said of the reasons which led to designation of the region of 

 the temporal lobe close behind the fissure of Sylvius with 

 hearing. The region marked on the diagram as that of 

 cutaneous sensations has also a doubtful claim : there is some 

 reason to believe that the motor area of the cortex has con- 

 nection with the muscular sense; also to some extent with 

 tactile feelings. 



Tactile and temperature impulses cross the middle line 

 somewhere on their path from the skin to the brain. An 

 apoplectic effusion in one cerebral hemisphere causes loss of 

 sensation and of voluntary movement on the other side of 

 the Body. 



The frontal lobes are quite irresponsive to excitation, and 

 considerable parts of them have been removed without ap- 



