362 NERVOUS SYSTEM. 



missural fibres connecting the two lateral halves of the 

 cerebellum, and assumes that the decussation between the 

 two sides takes place through a special system of decussating 

 prolongations from the cells of the cortical substance, which 

 he calls " intercortical commissural fibres." 1 This view, 

 however, is not adopted by the best anatomists ; but nearly 

 all agree that new fibres arise from the cells of the corpora 

 dentata and contribute to the formation of the peduncles. 



From the above sketch, the physiological significance of 

 the direction of the fibres, as appears from the most reliable 

 and generally-accepted anatomical investigations, is suffi- 

 ciently evident. By the superior peduncles, the cerebellum 

 is connected, as are all of the encephalic ganglia, with the 

 cerebrum ; by the middle peduncles, the two lateral halves 

 of the cerebellum are intimately connected with each other ; 

 and by the inferior peduncles, the cerebellum is connected 

 with the posterior columns of the spinal cord. "We shall 

 see, when we come to study the functions of the cerebellum, 

 that its connection with the posterior white columns of the 

 cord is a point of great interest and importance. 



General Properties of the Cerebellum. There is now 

 no difference of opinion among physiologists, with regard to 

 the general properties of the cerebellum. We may safely 

 discard the observations of Zinn and Haller upon this point, 

 for these experimenters, who conceived that irritation of the 

 cerebellum produced convulsive movements, 2 undoubtedly 

 stimulated portions of the medulla oblongata ; at least, this 

 must be assumed, if we accept the results of the more recent 

 experiments of Flourens, Longet, and many others. Flou- 

 rens, who made the first elaborate and entirely satisfactory 

 observations upon the cerebellum in living animals, noted, 



1 LUYS, Recherchcs sur le systeme nerveux cerebro-spinal, Paris, 1865, p. 126, 

 *t *eq. 



2 HALLER, Memoires sur la nature sensible et irritable des parties du corps 

 animal, Lausanne, 1756, p. 208. 



