460 Be II J. C. Griienberg 



is continued, and there is no nystagmus whatever. The head 

 turns to the left in that part of the rotation which carries the ani- 

 mal's body to its right, and vice versa, whether the rotation be 

 clockwise or the reverse, and without regard to the size of the 

 circle described; that is, without regard to the proximity of the 

 animal to one of the pivots. If the animal is placed in an opake 

 vessel and the rotation on the eccentric set up, there is no response 

 whatever. 



To show the effects of the various factors that have been con- 

 sidered as having a possible relation to the "compensatory move- 

 ments," the following comparative table maybe helpful. In the 

 experiments whose results are given under I the animal was 



I n 



A B C D 



Facing Periphery Facing Pivot Facing Periphery Facing Pivot 



I Air pressure ^- — -^ ■^^ ^- 



^ ^ ^ ^ 



2 Inertia (of viscera, 

 Ivmph, etc.) 



3 Centrifugal action 



t ^ ^ 4, 



4 Friction of support ^y •^- ^ ^ 



5 Displacement of retinal 



image 



6 "Spin" 



Q Q O O 



Response ■^^ — ■^- ^^ — ^^ 



rotated to the right (clockwise) on the ordinary turntable; in those 

 represented under II the eccentric arrangement was used and 

 the results given are for a portion of the revolution only, since a 

 continuation of the rotation beyond 180° is virtually equivalent 

 to a reversal of the motion. (It is of course understood that the 

 rotations in the reverse direction gave corresponding results but 

 in the opposite sense.) The arrows indicate the directions in 

 which the respective factors are supposed to act. 



