OF THE NEKVUS OCTAVUS. 31 



had shortly after the operation. The turning of head and neck 

 being thus gradually reduced, and at the same time the number 

 of fits diminishing, in which an acute and excessive turning of the 

 head called forth in periodical returns the acme, the rollings of the 

 animal have ceased likewise and do not return. A permanent 

 deviation of the head and neck of the animal remains, and in the 

 rabbit this is never entirely compensated. The turning of the head 

 on the cervical part of the body , towards the operated side , does 

 again allow the animal to be sitting on its four legs. 



The fact , that the revolutions cease , when the deviation of the 

 anterior part of the body is corrected so far that sitting is made 

 possible again, offers a strong argument for the presumption: that 

 the revolution is quite dependent on the intensity of the turning 

 of neck and head. 



Still there is another, very important argument for this opinion. 

 The animal, though rolling with the utmost violence, can be relea- 

 sed immediately from these revolutions, if the other labyrinth is 

 also removed. By this second operation the turned position of head 

 and neck has likewise ceased as by enchantment , and also has the 

 deviation of the eyes disappeared in consequence of it. 



As soon as by an operation , removing both labyrinths , the inner- 

 vation-defect has become nearly equal on both sides, the turning 

 of head and neck does not appear, neither the revolution round 

 the longitudinal axis of the body. 



One of the phenomena described above, viz. the revolution round 

 the longitudinal axis of the body, may therefore be considered as 

 a consequence of the turning of head and neck; another, viz. the 

 hyperextended-abduced position of the opposite fore-leg, may be 

 necessitated partly by the changed upward position of the opposite 

 shoulder, on the operated side the shoulder being turned downward. 



Both phenomena are therefore dependent on the turning of head 

 and neck, this latter may be said to belong to the primary distur- 

 bances of motion. Rolling and the characteristic position of the 

 foreleg are secundary to it. 



Not so easy it is, to elucidate if there is connection between 

 the position of the head and neck and the deviation of the eyes. 



b. Turning of head and neck and the deviation of the eyes. 



After a complete removal of the labyrinth, head and neck are 

 never to regain their original position. All phenomena that did appear 

 directly after the operation, continue to exist in a lesser degree. 

 The neck is bent on the trunk, the head is generally turned so 

 far on the neck, that the cheek on the operated side is looking 



