THE CEREBRO-SPINAL NERVOUS SYSTEM. 



517 



According to the observations of Ferrier, confirmed and extended by later 

 experimenters, stimulation of various parts of the monkey's brain, as in- 

 dicated by the numbers in Figs. 356, 357, produces movements of 

 definite muscles, thus: 



Stimulation of the districts marked 1, causes movements of hind foot; 

 of 2, chiefly adduction of the foot; of 3, movements of hind foot and tail; 



s 



FIG. 355. 



FIGS. 354 and 355. Brain of dog, viewed from above and in profile. F, frontal fissure, some- 

 times termed crucial sulcus, corresponding to tiie fissure of Rolando in man; S, fissure of Sylvius, 

 around which the four longitudinal convolutions are concentrically arranged; 1, flexion of head on 

 the neck, in the median line ; flexion of head on the neck, with rotation towards the side of the 

 stimulus; 3, 4, flexion and extension of anterior limb; 5, 6, flexion and extension of posterior limb; 

 7, 8, 9, contraction of orbicularis oculi, and the facial muscles in general. The unshaded part is 

 that exposed by opening the skull. (Dalton.) 



of 4, of latissimus dorsi; of 5, extension forward of arm; a, I, c, d, 

 movements of hand and wrist; of 6, supination and flexion of forearm; 

 of 7, elevation of the upper lip; of 8, conjoint action of elevation of 



