

OF THE CEREBELLUM, AND ITS FUNCTIONS. 735 



ments ; and this notion derives confirmation from the marked structural con- 

 nection which exists between the Cerebellum and the Optic Ganglia (corpora 

 quadrigemina), the purpose of which maybe not unfairly surmised to be, to commu- 

 nicate the guidance of the visual sense to the organ by which the co-ordina- 

 tion of motions is effected, in the same manner as the impressions appertaining 

 to the muscular sense are transmitted upwards by the Restiform columns. The 

 chief objection to such a view would seem to lie in the strong similarity between 

 the " muscular" sense and " common" or " tactile" sensation, which makes it diffi- 

 cult to conceive that they should have different seats in the Sensorium commune. 

 But this difficulty is diminished if not removed by the reflection, that the Resti- 

 form columns appear to have the same endowments as the remainder of the Sen- 

 sory tract derived from the posterior columns of the Spinal Cord : and that no 

 explanation can be given of their extreme sensitiveness to impressions (as shown 

 by experiment), unless it be admitted that the organ in which they terminate 

 is itself a centre of a form of sensation closely allied to that of the common or 

 tactile kind. Possibly, however, the true termination of these fibres is in the 

 " corpus dentatum" of the Crura Cerebelli ; and the Cerebellum may only react 

 upon impressions thence transmitted to it, without being itself the instrument 

 of communicating such impressions to the consciousness. 



767. We have now to examine, however, another doctrine regarding the functions 

 of the Cerebellum, which was first 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 not altogether incompatible 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 the evidence in support 

 of this position, afforded by the three methods of inquiry which have been al- 

 ready indicated. In the first place, it may be remarked that the sexual propen- 

 sity is very closely connected with various emotional states of mind to which 

 " organs" are assigned by Phrenologists, and of which the Cerebrum is univer- 

 sally admitted to be the seat ; such, for instance, as " love of offspring/' " ad- 

 hesiveness," and in the lower animals more particularly with " combativeness ;" 

 and in Man it has a continual operation upon the reasoning faculties and the 

 Will. Yet the anatomical connections of the Cerebellum are peculiarly unfa- 

 vorable to any such influence ; these being, as we have seen, rather with the 

 lower than with the higher portion of the Cerebro-spinal axis. Again, the re- 

 sults of fair observation as to the comparative size of the Cerebellum in differ- 

 ent animals can scarcely be regarded as otherwise than very unfavorable to 

 the doctrine in question. In the greater number of Fishes, it is well known 

 that no sexual congress takes place ; the seminal fluid being merely effused, like 

 any other excretion, into the surrounding water ; and being thus brought into 

 only accidental contact with the ova, of which a large proportion are never fer- 

 tilized. But there are certain Fishes, as the Sharks, Rays, and Eels, in which 

 copulation takes place after the ordinary method. Now on contrasting these 

 groups, we find no corresponding difference in the size of the Cerebellum. It is 

 true that this organ is of large size in the Sharks ; but it is smaller in the Rays, 

 and almost rudimentary in the Eels ; in this respect bearing a precise corre- 

 spondence with the variety and complexity of their movements. Further, in 

 many ordinary Fishes, which do not copulate, such as the Cod, the Cerebellum 

 is not only larger, but more complex in structure, than it is in the generality of 

 Reptiles, in which the sexual instinct is commonly strong ; the whole spinal 

 system of the Frog possessing, at the season of reproduction, an extraordinary 

 degree of excitability, which is evidently destined to aid in the performance of 

 the function. Again, on comparing the Gallinaceous Birds, which are poly- 



