34 BRAINS OF RATS AND MEN 



Indeed, some of the facts to be reviewed shortly seem 

 to indicate that both of these types of cortex act 

 largely through reinforcement or activation of lower 

 centers, but in a different way. Further experimental 

 work is necessary to clarify this subject. 



The dominance of the vestibular organs in pro- 

 prioceptive control is maintained to the end of the 

 history of cerebellar evolution. Even in the human 

 brain some fibers of the vestibular nerve pass directly 

 from their peripheral end-organs into the cerebellum. 

 The result is that the cerebellum is permanently 

 anchored in the immediate neighborhood of the 

 vestibular nerves. 



The apparatus of exteroceptive control of behav- 

 ior, that is, of adjustment to the outside events going 

 on in the world in which we live, has had a very differ- 

 ent and much more diversified history. This theme 

 has been elaborated by Sherrington (1906, pp. 324 ff,) 

 in his illuminating discussion of the significance of 

 the "distance-receptors" and the consequences which 

 follow from the dissociation in time of "anticipatory 

 reactions" from "consummatory reactions." The dis- 

 tance-receptors, he says, "contribute most to the up- 

 rearing of the cerebrum." This principle will be re- 

 peatedly illustrated in the course of the following 

 pages. 



Some particular sense organ may be very highly 

 developed — eyes in the trout, nose in the shark, taste 

 buds in the carp — and the entire action system is 



