196 FUNCTIONS OF THE NERVOUS SYSTEM. 



instinctive fondness for her offspring, in allowing it gratifications which she 

 knows to be injurious to it, is placing herself below the level of many less 

 gifted beings. The habit of yielding to a natural infirmity of temper often 

 leads into paroxysms of ungovernable rage, which, in their turn, pass into a 

 state of maniacal excitement. It is not unfrequently seen, that a delusion of 

 the intellect (constituting what is commonly known as Monomania), has in 

 reality resulted from a disordered state of the feelings, which have represented 

 every occurrence in a wrong light to the mind of the individual. All such 

 conditions are of extreme interest, when compared with those which are met 

 with amongst idiots, and animals enjoying a much lower degree of intelligence ; 

 for the result is much the same, in 'whatever way the balance between the 

 feelings and the judgment (which is so beautifully adjusted in the well-ordered 

 mind of Man), is disturbed, whether by a diminution of the intelligence, or 

 by an exaltation of the feelings. These views will probably be found correct, 

 whatever be the truth of the speculation with which they have been here 

 connected, as to the part of the Nervous system concerned in the performance 

 of the purely Emotional actions. That their channel is alike distinct, how- 

 ever, from that of the voluntary movements, and from that of reflex operations, 

 must be apparent to any one who fairly weighs the evidence. 



XIX. Functions of the Cerebellum. 



286. In regard to the particular purposes which are served by the Cere- 

 bellum, physiologists are still much in the dark ; although there are not 

 wanting those who consider them well ascertained. That this organ has 

 some special function, distinct from that of the Cerebral hemispheres, can 

 scarcely be doubted ; since its peculiar structure and position, its independent 

 connections with the Medulla Oblongata, and its extremely variable size rela- 

 tively to the remainder of the Encephalon, point it out as an instrument 

 adapted to some particular purpose. We shall inquire briefly into the nature 

 of the evidence respecting its function, which is supplied to us by Comparative 

 Anatomy, by Experiment, and by Pathological phenomena. A Cerebellum 

 is found in all Vertebrated animals ; although it is in some extremely small, 

 looking like a little prominence on the Medulla Oblongata. When this is the 

 case, it is observed that the whole mass is not a miniature (so to speak) of the 

 large Cerebellum of Man, but that the central portion (termed the vermiform 

 process) is the part most developed ; the lobes not presenting themselves until 

 the organ has acquired an increased dimension. The following table, con- 

 structed from materials contained in M. Serres' most valuable Comparative 

 Anatomy of the Brain, will afford some idea, of the materials for speculating 

 on the nature of the function of the Cerebellum, which we obtain from this 

 source. The first column gives the diameter of the Spinal Cord at the second 

 cervical vertebra ; in the two succeeding columns are stated the transverse and 

 the antero-posterior diameters of the Cerebellum ; these dimensions are stated 

 in hundred-thousandths of a metre. The fourth column expresses, in round 

 numbers, the proportion which the diameters of the Cerebellum bear to that of 

 the Spinal Cord ; the latter being reckoned as 1. 



