THE NERVOUS SYSTEM. 



133 



points in a horizontal section, through the deeper parts of the hemi- 

 spheres, produces the same effects as stimulation of the so-called "centres" 

 in the grey matter overlying them: while the same results follow electric 

 stimulation of different points of the corpus striatum. 



FIG. 344. 



FIGS. 343 and 344. Diagrams of monkey ''s brain to show the effects of electric stimulation of cer- 

 tain spots. 1, movement of hind foot; 2, chiefly adduction of foot; 3, movements of hind foot and 

 tail; 4, of latissimus dorsi; 5, extension forward of arm; a, 6, e, d, movements of hand and wrist; 6, 

 supination and flexion of forearm; 7, elevation of upper lip; 8, conjoint action of elevation of upper 

 lip and depression of lower; 9, opening of mouth and protrusion of tongue; 10, retraction of tongue; 

 11, action of platysma; 12, elevation of eyebrows and eyelids, dilatation of pupils, and turning head 

 to opposite side; 13, eyes directed to opposite side and upward, with usually contraction of the 

 pupils; 13', similar action, but eyes usually directed downward: 14, retraction of opposite ear, head 

 turns to the opposite side, the eyes widely opened and pupils dilated; 15, stimulation of this region, 

 which corresponds to the tip of the uncinate convolution, causes torsion of the lip and nostril of the 

 same side. (Ferrier.) 



In applying the facts ascertained by these experiments to elucidate 

 the physiology of the human brain, we must remember that the method 

 of electric stimulation is an artificial one, differing widely from the ordi- 

 nary stimuli to which the brain is subject during life. 



