162 HUMAN PHYSIOLOGY 



Purkinje's cells the outgoing fibres of the cerebellum pass 

 into the white matter, to the roof nuclei, and hence to 

 Deiters' nuclei (Fig. 86). 



2. Connections. The cerebellum is connected (Fig. 

 88): 



i. With the Spinal Cord. 



a. Incoming Fibres. 1. The direct cerebellar tract (p. 156) 

 passes up in the restiforin body to end chiefly in the superior 

 vermis. 2. The ascending antero-lateral tract (p. 156) passes 

 to the cerebellum in the superior peduncle and ends in 

 the superior vermis. 3. Fibres from the nuclei of the 

 posterior columns of the same side (Fig. 83, p. 156) pass 

 in the restiform body to the cerebellum. 4. Fibres from 

 the vestibular root of the eighth nerve also pass to the 

 cerebellum (p. 137). 



6. Commissural Fibres. Strong bands of fibres connect 

 the inferior olive of one side with the dentate nucleus of 

 the other. 



c. Outgoing Fibres. Fibres pass from the superior vermis 

 to the roof nuclei, and, from these, fibres pass on to Deiters' 

 nuclei (Fig. 86, p. 159), from which fibres pass down in the 

 descending antero-lateral tract of the cord. 



ii. With the Cerebrum. 1. The fibres of the middle 

 peduncles cross in the middle line embracing the medulla, 

 and become associated with cells from which fibres pass up 

 in the lateral parts of the crura cerebri to the cerebral 

 cortex (Fig. 90, CO. CO., p. 167). 2. The fibres of the superior 

 peduncle cross and end in the red nuclei (Fig. 90, S.C.P.), 

 from which fibres seem to pass upwards to the cerebrum. 

 How far these are upward conducting and how far down- 

 ward is not definitely known. 



3. Functions. Removal of the cerebellum deprives the 

 animal, for a time at least, of the power of balancing itself. 

 This may be easily demonstrated in the pigeon (Fig. 95, 

 p. 171). But in some cases, when slowly progressing disease 

 has destroyed the organ, no loss of equilibration has appeared, 

 and in other cases the cerebellum has been congenitally 

 almost absent, and yet the individual has not shown any 

 sign of want of power of maintaining his balance. Evi- 



