OF THE NERWS OCTAYUS. 39 



hand of ;i watch-work) or proceed but very little (and in such a 

 case the animal moves with a manege-gait). 



6. A comparison bet'ioeen pigeons after one-sided removal of the 

 labyrinth and rabbits after the same operation. 



In many respects the accordance is perfect between the distur- 

 bances of motion observed in rabbits after one-sided extirpation of 

 the labyrinth, and those -found in pigeons. Those in pigeons 

 have been so carefully described by EWALD, that it is not necessary 

 to describe them ngain, for I have nothing to add to the magistral 

 picture, which that author has drawn. 



Both animals present the peculiar turning of neck and head, the 

 atony of the extremities at the operated side. However, there remains 

 also an essential difference between the disturbances of motion 

 observed in both animals. The rabbit , immediately after the removal 

 of the labyrinth, shows the excessive deviation of the eyes and 

 the excessive turning of head and neck with hyperextended and 

 abduced position of the opposite upper extremity ; it is rolling 

 round its longitudinal axis in the direction of the operated side 

 and both extremities on that side are atonic. Gradually these symp- 

 toms are to some degree corrected , the rolling ceases , and the 

 animal continues its customary life with its twisted head, as if 

 nothing had happened. The pigeon on the contrary offers but few 

 phenomena directly after the one-sided removal of the labyrinth. 

 It may walk somewhat unsteadily and with wide-extended legs, 

 its head is unsteady and tottering, but the animal does not roll 

 and shows no turning of neck and head. This turning does begin 

 only after a few days, and the symptom is complete only with the 

 2 d and 3' 1 week after the operation. Moreover it is there no per- 

 manent symptom. Only the turning of the neck appears on the 

 slightest occasion, though intervals occur during which the head is 

 kept straight. 



The maximal deviation of the eyes however does not exist in 

 tin; pigeon, and rolling does never occur in uncomplicated cases. 

 Nevertheless, in my opinion, these differences do not constitute an 

 essential difference. 



The pigeon does not roll round its longitudinal axis like the 

 rabbit. But the pigeon has a long and easily movable neck, that 

 may without any difficulty be laid down on the ground with its 

 middle-part and so offer a support there, whilst the head is tur- 

 ned so far that the beak is looking upward, or even farther (see 



