VIII 



THE HIND-BKAIN 



475 



For an exact description of these, the student must refer to Bolk's 

 original monograph. 



We shall now see how far Bolk's inductions founded on com- 

 parative anatomy have been confirmed by physiological experi- 

 ment, either by the method of electrical, mechanical, and chemical 

 stimulation of different parts of the brain, or by the removal of 

 single segments. 



After Hitzig and Fritsch had demonstrated the possibility of 

 localising certain motor centres in the cerebral cortex by electrical 

 stimulation (Chap. X.) Ferrier (1879) made use of this method, 

 not merely in developing the theory of cerebral localisation, but 

 also in attempting to extend it to the cerebellar cortex. The 



:v'" 



for/natio vermtcatarif 



FIG. 239. Diagram of lobules of mammalian cerebellum. (After Bolk, simplified by van Rynberk.) 

 Left side of figure gives Bolk's new terms for the lobules ; right side, the probable localisation, 

 according to Bolk, of the relation in different mammals between lobular development and 

 the functional development of different groups of muscles. 



motor effects which Ferrier obtained by faradisation of various 

 points of the surface of the cerebellum in the ape consisted in 

 associated movements of the eyeball to the right or left, upward 

 or downward, according as the stimulus was applied to the right 

 or left half, or to the anterior or posterior part of the median 

 lobe of the cerebellum. Movements of the head, as well as certain 

 ali u]tt movements of the limbs on the side excited, were often 

 associated with those of the eyes. 



Ferrier's results were not, however, confirmed by Mendelsohn 

 with induced currents. Ferrier employed such strong currents 

 that they may have spread to adjacent regions, as the corpora 

 quadrigemiiia, pons, bulb. 



Nothnagel (1876) performed a number of experiments on 

 rabbits with mechanical stimulation, by running a needle into 

 different points of the cerebellar cortex. Among the effects of 



