2C2 AVERS. [Vol. VI. 



that we have here to deal with a disturbance of the relations of 

 the otoliths to the sensory hairs. The otoliths when disturbed 

 in the normal relations would cause many kinds of distortions of 

 the sensory hairs, such as bending, crushing, or even breaking, 

 and in this way irritate the central end cells by a stream of 

 abnormal impulses in such manner as to cause confusion in the 

 auditory co-ordinating apparatus, or if continued beyond the 

 limit of reaction it would produce exhaustion of the apparatus 

 so used and by sympathetic relations the motor disturbances. 

 Owing to the absence of otoliths from the ampullae these dis- 

 turbances would not be kept up after the first injury had been 

 accomplished. Be this as it may. 



Steiner has shown that medullary lesions of a light nature are 

 within certain bounds capable of producing greater disturbance 

 than the more extensive section of half the cord. Consequently 

 the slight injury to the medullary acustico-facial nucleus caused 

 by the dissection of the utriculo-sacculus and the injury of the 

 sense organs contained gave rise to no unusual or exceptional 

 phenomena ; Steiner found also that the neighborhood of the 

 acustico-facial nucleus was the most sensitive region of the 

 whole medulla in sharks, and I am able to confirm his con- 

 clusion from my own experiments on frogs by means of the 

 electric current ; other points on the floor and side walls vary a 

 great deal in their relative sensitiveness. 



The final conclusion is as follows : " Nehmen wir Alles zu- 

 sammen, so folgt, dass die halbzirkelformigen Canale der Hai- 

 fische so wenig wie der N. aciLsticus zu den Bewegungen resp. 

 deren Gleichgegwicht in irgend welcher unmittelbaren Beziehung 

 stehen, und dass die Storungen, welche Man nach mechanischem 

 Angriff auf den Vorhof thatsachlich beobachtet, Zvvangs bewe- 

 gungen sind, welche ihre Ursache in einer mittelbaren Lasion 

 des Nackenmarkes an der centralen Ursprungstelle des Hor- 

 nerven haben." 



This demonstration is as definite in result as it is decisive of 

 the canal question so far negating, the assumed functions. Con- 

 sidering the ease with which it is performed, we can hardly 

 understand why it had been so long postponed. 



As Foster has shown, in those experiments involving the use 

 of several special senses, the organs supposed to be special 

 organs of equilibration are found to be less potent in this regard 



