THE NERVOUS SYSTEM AND CONSCIOUSNESS. 69 



Fig. 2. Lateral Aspect op Monkey's Brain, showing 

 the relative positions of the so-called " Motor Centers " 

 in the left Cerebral Hemisphere. (Ferrier.) 



the most interesting of these animals to us, from the striking resem- 

 blance between his brain and the human brain. 



Hitzig's investigations, published in Berlin in 1874, give all the 

 results gained up to that time by the stimulation experiments. Fer- 

 rier's book, " The Functions of the Brain," London, 1876, better known 

 to English readers, has spe- 

 cial merit in two respects. 

 It displays a very intelli- 

 gent comprehension of the 

 consequences of electrical 

 stimulation, and seems to 

 give a juster account of the 

 motor regions in the mon- 

 key's brain than was fur- 

 nished by Hitzig. 



Figs. 2 and 3 will show 

 the character and results of 

 these experiments in suf- 

 ficient detail. 



When center No. 1 is stimulated, the hind-limb on the opposite 

 side of the body advances as in the act of walking ; when No. 5 is 

 stimulated, the opposite arm and hand reach forward as if to touch 

 something. These movements go together and are essentially the 

 same. Centers 2 and 3 work to- 

 gether ; when 2 is stimulated, there 

 are combined movements of the 

 opposite thigh, leg, and foot, and 

 the foot is brought to the middle 

 line of the body as in scratching 

 that part, or in seizing something 

 with the foot ; 3 gives movements 

 of the tail. An interesting fact 

 should be noted at this point. 

 There is no center No. 2 in the 

 brain of cat, dog, or jackal, while 

 No. 3 is present in each. These 

 animals do not grasp with the foot, 

 and the monkey alone uses the rear 

 foot for seizing. That No. 2 should 

 be present, and of great size, in the 

 monkey's brain, while absent else- 

 where, is confirmatory of the ac- ^Z^*^ n %^j %% 

 curacy of the experiments. The ^^g^JK K) ta ^ teft 

 centers marked a, b, c, d, are on 



the ascending parietal convolution. "When stimulus is applied there, 

 the fingers and wrist move with separate and combined movements 



