SEC. 10. SOME OTHER ASPECTS OF THE FUNCTIONS 



OF THE BRAIN. 



687. It is difficult to say anything definite concerning the 

 transmission of sensory impulses and the development of sensa- 

 tions; it is still more difficult to say anything definite, beyond what 

 has been already incidentally said, concerning the parts played 

 in the work of the brain by the various aggregations of grey 

 matter and tracts of fibres forming the middle part of the brain. 

 Neither experiment nor clinical study has as yet afforded any 

 clear or sure leading. 



To what has already been said about the cerebellum, we may 

 add the following. 



Electrical stimulation of the surface of the cerebellum, in the 

 monkey and in other animals, has led to movements of the eyes, 

 and of other parts of the head ; but we cannot from such results 

 draw any satisfactory inferences. 



The removal of various parts of the cerebellum, especially 

 of the median parts, has led to a want of coordination in bodily 

 movements ; and an unsteady gait, due to a like want of ade- 

 quate coordination, is a frequent symptom of cerebellar disease. 

 But the incoordination which makes its appearance immediately 

 after removal of, or injury to, the cerebellum may eventually 

 disappear, even though large portions have been removed ; and 

 many cases of extensive cerebellar disease have been recorded in 

 which the most perfect coordination of movements was retained. 

 Hence the results of experimental and clinical study, while on the 

 whole supporting the conclusion that the cerebellum has in some 

 way to do with coordination, throw little or no light on the exact 

 nature of the part which the organ plays in the complex process, 

 but perhaps rather shew that we are at present wholly ignorant 

 of how coordination is brought about. 



Many hypotheses have been put forward as to the work 

 carried out by the cerebellum, but none of these can be said to 

 have an adequate basis. And, indeed, if there be any value in the 

 reflections we have repeatedly made in previous pages, the 

 physiologist ought not to use the words "functions of the 

 cerebellum." From a physiological point of view it is, so to speak, 



