68 THIRD REPORT — 1833. 



attempted to rush forwards, and, if restrained, appeared rest- 

 less, continuing in the attitude of incipient progression. One 

 thalamus opticus was then cut away from the same animal. The 

 direction of its motion was immediately changed from a straight 

 to a curved line. It continued for some time to run round in 

 circles, turning towards the injured side. When the other 

 thalamus was removed, the animal ceased its motions and re- 

 mained perfectly tranquil, with the head inclined backwards. 

 These experiments, it may be observed, furnish no support to 

 the opinions of MM. Foville and Pinel Grandchamps, who have 

 assigned the anterior lobes and corpora striata as the parts 

 presiding over the movements of the inferior extremities, and 

 the posterior lobes and thalami as regulating the superior. 



Cerebelhim. — It may be regarded as nearly established by 

 modern researches, that the cerebellum is more or less directly 

 connected with the function of locomotion. The precise nature 

 and extent of its control over the actions of the voluntary 

 muscles are, however, far from being clearly determined. In 

 the higher animals, the mental act of volition probably has its 

 commencing point, as productive of a physical change, in the 

 brain-proper ; though it must be confessed that some of the 

 experiments of Flourens, and all of those of Bouillaud, indicate 

 the persistence of many instinctive, and even of some automatic 

 motions, after destruction of the brain. But there does appear 

 sufficient evidence to prove that those volitions which have 

 motion as their effect, whatever be their origin, whether in the 

 cerebrum, cerebellum, or medulla oblongata*, require for their 

 accomplishment the cooperation of the cerebellum. This evi- 

 dence has been mainly supplied by the same inquirers whose 

 researches on the cerebrum have been already analysed. 



In the order of time, though not of importance, the experi- 

 ments of Professor Rolando stand foremost. Injuries of the 

 cerebellum, he observed, were always followed by diminished 

 motive power ; and this partial loss of power was always in 

 direct proportion to the amount of injui-y. A turtle survived 

 upwards of two months the entire removal of the cerebellum, 

 continuing sensible to the slightest stimulus ; but when irritants 

 were applied, it was totally unable to move from its place. 

 M. Flourens has since arrived at similar, but more definitive 

 results. He removed in succession thin slices from the cere- 

 bellum. After the first two layers had been cut away, a slight 

 weakness and want of harmony and system in the automatic 

 movements were noticed. When more cerebellic substance had 



* Flourens, Mhnoires de I' Academie, torn. ix. 



