200 FUNCTIONS OF THE NERVOUS SYSTEM. 



an effort to advance ; and that, if the Crus Cerebelli on one side be injured, 

 the animal is caused to roll over towards the same side. Sometimes (if Ma- 

 gendie's statements can be relied on), the animals made sixty revolutions in a 

 minute, and continued this movement for a week without cessation. Division 

 of the second Crus Cerebelli restored the equilibrium. Hertwig observed the 

 s*me phenomenon, when the Pons Varoiii (which is nothing more than the 

 commissure of the Cerebellum, surrounding the Crura Cerebri) was injured 

 on one side ; and he has also remarked, that the movements of the eyes were 

 no longer consensual. 



272. On turning to Pathology for evidence of the functions of the Cere- 

 bellum, we meet with much that seems contradictory. It must be remembered 

 that a sudden effusion of blood, even to a small extent, in any part of the 

 Encephalon, is liable to produce the phenomena of apoplexy or paralysis ; 

 and inferences founded upon the phenomena exhibited after sudden lesions of 

 this description are, therefore, much less valid than those based on the results 

 of more chronic affections. ' In regard to these last, however, it is to be 

 observed, that we are not yet in a condition to be able to state with precision, 

 what amount of morbid alteration in any part of the nervous centres is com- 

 patible with but slightly disturbed performance of its function ; and that cases 

 are every now and then occurring, which would upset all our previous notions, 

 if we were not aware that the same difficulty presents itself even in regard 

 to the best-established results in Neurology. It is also to be remembered, that 

 the results of disease, occasioning pressure, will be peculiarly liable to affect 

 the Medulla Oblongata, as well as the Cerebellum 1 , and will thus occasion a 

 greater loss of motor power than would be occasioned by the mere suspension 

 of the function of the latter. 



273. Pathological phenomena, when examined with these reservations, 

 appear to coincide with the results of experiment, in supporting the conclu- 

 sion, that the Cerebellum is not in any way the instrument of psychical opera- 

 tions. Inflammation of the membranes covering it, if confined to that part, 

 does not produce delirium ; and its almost complete destruction by gradual 

 softening, does not appear necessarily to involve loss of intellectual power. 

 " But," remarks Andral, " whilst the changes of intelligence were variable, 

 inconstant and of little importance, the lesions of motion, on the contrary, were 

 observed in all the cases [of softening which had come under his notice] ex- 

 cept one ; and in this it is not quite certain that motion was not interfered 

 with." In general, apoplexy of the Cerebellum is accompanied by paralysis ; 

 but this is by no means usual in cases of chronic disease, in which there is 

 rather an irregularity of movement, with a degree of restlessness, resembling 

 that described by Flourens as resulting from partial injury of this organ. In 

 a few cases in which both lobes of the Cerebellum have been seriously affected, 

 the tendency to retrograde movement has been observed ; and instances are 

 also on record, of the occurrence of rotatory movement, which has been found 

 to be connected with lesion of the Crus Cerebelli on the same side. So far 

 as they can be relied on, therefore, the results of the three methods of investi- 

 gation bear a very close correspondence ; and it can scarcely be doubted, that 

 they afford us some approximation to truth. 



274. We have now to examine^ however, another doctrine regarding the 

 functions of -the Cerebellum, which was propounded by Gall, and which is 

 supported by the Phrenological school of physiologists. This doctrine that 

 the Cerebellum is the organ of the sexual instinct is by no means incom- 

 patible with the other ; and by some it has been held in combination with it. 

 The greater number of phrenologists, however, regard this instinct as the 

 exclusive function of the Cerebellum ; and assert that they can judge of its 

 intensity, by the degree of development of the organ. We shall now examine 



