OF THE CEREBELLUM, AND ITS FUNCTIONS. 733 



however, was completely destroyed ; except so far as those actions (as that of 

 Respiration) were dependent only upon the reflex function of the Spinal Cord. 

 The experiments afforded the same results, when made upon each class of Ver-' 

 tebrated animals ; and they have since heen repeated, with corresponding effects, 

 by Bouillaud and Hertwig. The latter agrees with Mourens, also, in stating 

 that the removal of one side of the Cerebellum affects the movements of the 

 opposite side of the body ; and he further mentions that, if the mutilation of 

 the Cerebellum have been partial only, its function is in great degree restored. 1 



764. It was further affirmed by Magendie, that the removal of the Cere- 

 bellum, or the infliction of a deep wound of its substance on both sides, occa- 

 sions the animal to move backwards as if by an irresistible impulse j and this 

 he attributed to the retrograde power of the Corpora Striata, which now acts 

 without its due balance. That such a movement does sometimes present itself 

 after such injuries as have been described cannot be questioned, th$ fact having 

 been confirmed by other experimenters ; but it is a phenomenon of such rarity, 

 that it cannot be rightly considered as having any direct dependence upon the 

 injury of the Cerebellum, but must be rather set down to some accidental com- 

 plication or concurrent disturbance ; more especially since, as already pointed 

 out ( 737), the function attributed by Magendie to the Corpora Striata has no 

 real existence. But the results of section of one of the Crura Cerebelli, which 

 were first obtained by Magendie, are much more constant ; for the performance 

 of this operation causes the animal to fall over upon one side, and to continue 

 rolling upon its longitudinal axis, even as fast (in some instances) as sixty times 

 in a minute, the movement going on for many days without intermission. There 

 is a remarkable difference in the statements of different experimenters, however, 

 as regards the direction of this rolling movement ; for, whilst Magendie and 

 Miiller affirm that it takes place towards the injured side, Longet and Lafargue 

 assert that it takes place from the injured side towards the opposite side. This 

 discrepancy appears, from the experiments of Schiff, 2 to be due to a difference 

 in the locality of the section ; for he states that if the peduncle be divided from 

 behind, the animal turns towards the side on which the section is made ; whilst 

 if the section be made in front, the animal turns from that side towards the 

 opposite one. This difference is explained by Longet, by the difference in the 

 course of the anterior and posterior fibres of the peduncles ; for according to 

 him the former communicate with the decussating, and the latter with the non- 

 decussating portion of the motor tract ; so that, when the former are injured, 

 the animal loses control over the muscles of the opposite side, and when the 

 latter, over the muscles of the same side. This rolling movement is attributed 

 by some to the continued activity of the muscles of one side, now unbalanced 

 by that of the muscles on the other ; but if such were the case, as Longet 

 justly remarks, it ought to occur more frequently than it does in cases of ordi- 

 nary hemiplegia ; and according to that experimenter, observation shows that 

 it rather depends on a twisting movement of the spinal column, especially affect- 

 ing its anterior portion, and dragging the posterior (as it were) after it. 3 



765. The information supplied by Pathological phenomena, when interpreted 

 with the cautions formerly referred to, is found on the whole to coincide with 



1 All these results are objected to by those who assert that the Cerebellum is the seat of 

 the sexual instinct, on the ground that the observed aberrations of the motor functions are 

 sufficiently accounted for by the general disturbance which an operation so severe must 

 necessarily induce. The fallacy of this objection, however, is shown by the fact that 

 the much more severe operation of removing the Hemispheres does not occasion such an 

 aberration ; the power of performing the associated movements, and of maintaining the 

 equilibrium, being remarkably preserved after the loss of them ($ 734). 



2 " De vi motoria baseos encephali inquisitiones experimentales;" Bockenhemii, 1845. 



3 See his " Traite de Physiologic," torn. ii. partie 2, pp. 216, 217. 



