TIIE CEREBRUM, AND ITS FUNCTIONS. 



699 



part of the cortex of the cerebrum, the several centres lying in it from the 

 median fissure downwards to the Sylvian fissure. He maintained that about 

 3 mm. from the median line is the centre for the posterior extremity of the 

 opposite side, and about 3 mm. further outwards that for the anterior ex- 

 tremity. Seven mm. beyond this laterally is the centre for a part of the 

 muscles associated with the visual organs, and close to the Sylvian fossa a 

 fourth centre governing the muscles of the mouth, tongue, and jaw of both 

 sides. Weak currents applied to the parietal and frontal regions were not 

 followed by any movements. In a still more recent short communication l 

 he states that he had found lesion of the posterior convolutions (occipital) 

 of the cerebral hemispheres produces blindness of the opposite eye and para- 

 lytic dilatation of the corresponding pupil. Soon after the appearance of 

 the first series of observations made by Fritsch and Hitzig, their results were 

 confirmed and extended by Ferrier 2 in his experiments with the Faradic 

 current in reference to the theories of epileptic discharges propounded by 

 Hughlings Jackson. He defined on the surface of the brain of cats, dogs, 

 and rabbits the different centres from which various movements of the limbs, 

 face, mouth, and tongue, eyes, ears, etc., could be definitely and distinctly 

 excited. Carrying his investigations to the brain of monkeys, Ferrier 3 has 



FK;. 2-16. 



FIG. 247. 



Diagram of the Brain of Monkey to show the effects of electrical stimulation of certain points as 

 given in the text. In each instance the effects produced resulted from, the application of the two elec- 

 trodes to the area circumscribed by the circle. 



mapped out the following regions, the stimulation of which gives results which 

 may thus be briefly stated (see Figs. 246, 247): 1. Movement of the hind 

 foot as in walking ; 2. Complex movements of the hind leg, consisting chiefly 

 in adduction of the foot to the middle line ; 3. Movements of hind foot and 

 tail ; 4. Action of the latissimus dorsi ; 5. Extension forward of the arm : 

 a, b, c, d. Different aspects of combined muscular movements of the hand 

 and wrist, which in their completes! action cause closure of the fist; 6. Action 

 of the biceps, supinatiou and flexion of forearm ; 7. Elevation of the upper 



1 Centrnlblatt f. d. Med. WUs., 1874, p. 548. 



2 West Hiding Asylum Reports, vol. iii, 1873. 3 Proc. Roy. Soc., No. 1G1, 1875. 



