OH. XLIX.] FUNCTIONS OF THE CEREBELLUM. 68l 



symptoms were observed in him during the rest of his life. He, 

 indeed, returned to his work as overseer of the mine. 



The large size of this portion of the brain is very distinctive of 

 the human brain, and it has therefore been supposed that here 

 is the seat of the intellectual faculties. This may be so, but 

 experimental physiology lends no support to this view, as the 

 sensory centres (and sensations are the materials for intellect) are 

 situated behind or within, and not in front of, the Rolandic area. 



A very large amount of the white matter of the brain is 

 composed of association fibres which link convolution to con- 

 volution. In the development of the brain these are the last 

 fibres to become inyelinated ; white fibres do not become 

 functional until they receive their medullary sheath. This 

 coincides with the well-known fact that association of ideas is the 

 last phase in the psychical development of the child. 



CHAPTER XLIX. 



FUNCTIONS OF THE CEREBELLUM. 



IN past times there have been several views held as to the 

 functions of the cerebellum. One of the oldest of these was the 

 idea that the cerebellum was associated with the function of 

 generation ; another view, first promulgated by Willis, was that 

 the cerebellum contained the centres which regulate the functions 

 of organic life ; this arose from the circumstance that diseases 

 of the cerebellum are often associated with nausea and vomiting ; 

 it is a familiar fact that in displacements of equilibrium such as 

 occur on board ship in a rough sea, or in the disease called 

 Meniere's disease, sickness is a frequent result ; it appears from 

 this that the cerebellum does receive from or send to the viscera 

 certain impulses. The third and last of these older theories was 

 that the cerebellum was the centre for sensation. This arose 

 from the fact that certain of the afferent channels of the spinal cord 

 were traced into the cerebellum. The impulses that travel along 

 these, however, though afferent, are not truly sensory, and their 

 reception in the cerebellum is not associated with consciousness. 



The true function of the cerebellum was first pointed out by 

 Flourens, and our knowledge about it has not advanced much 

 from the condition in which Flourens left it. He showed that 

 the cerebellum is the great centre for the co-ordination of muscu- 

 lar movement, and especially for that variety of co-ordination 

 which is called equilibration that is, the harmonious adjustment 



