81 

 The axone of the cell takes a more or less direct coarse oat 

 of the cereballurn, carry inf5 the resaltant of the nervous in- 

 teractioTS to the proper point for altimate distribution. If 

 it is the purpose of the whole series of cerebellar elements 

 to provide a central mechanisn of equilibration, then the neu- 

 rone of Purkinje is certainly the centre of that mechanism. 

 The various nerve-fibres sweeping into the cerebellum may ter- 

 minate in several ways and at diverse levels of the organ, but 

 everywhere there are devices for connectinf; them physiologic- 

 ally with the neurones of Purkinje, which receive all and pre- 

 side over all. 



The researches of Lee ('92, '93, '94, '98) upon equilibration 

 in fishes have shown with what nice discrimination these aquat- 

 ic animals balance themselves, devoid, as they are, of many 

 sources of impressions possessed by terrestrial vertebrates. 

 Doubtless a large number of equilibrial impressions are de- 

 rived from the visual mechanism of the fish. Axones from the 

 roof-nucleus of the midbrain pass backward into the cerebellum; 

 and it will be shown in Section VI that there is a most inti- 

 mate association between the roof-nucleus and optic termina- 

 tions. Another source of equilibrial impressions is to be 

 found in the fins and body musculature, entering the cerebellum 

 through the tractus cerebello-spinalis. But the work of Les 

 clearly demonstrates the overshadowing importance of the pis- 

 cine ear as a peripheral organ of equilibration. In fact, his 

 latest research ('9B) makes it clear that the great ear of 



