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plane. Whether, in this case, the sacculi or the utriculi are the cause 
of these reflexes, cannot yet be stated with certainty. 
3. Tonic labyrinth reflexes upon the eye muscles. 
a. Vertical deviations. 
In these tonic labyrinth reflexes one does best to proceed from 
the symptoms after uni-lateral labyrinth extirpation. 
After uni-lateral labyrinth extirpation, the strongest vertical deviation 
of the eyes will be found when the intact labyrinth is downwards, 
with the head lying on the cheek. The rectus sup. of the same 
side and the rectus inf. of the crossed side are then the most strongly 
contracted. When the intact labyrinth is above, the rectus sup. of 
the same side and the rectus inf. of the opposite side are least 
contracted. A tonic influence of the intact labyrinth upon the rectus 
sup. of the crossed side and the rectus inf. of the same side could 
not be demonstrated. 
With intact labyrinths and a normal position of the head, the 
stimuli from both labyrinths upon the recti sup. and inf. of both 
eyes are equally strong, so that the eyes in this case show no 
vertical deviation. 
As the maximum positions of the labyrinths differ about 180° 
(maximum position of the right labyrinth when lying on the right 
side, and of the left when lying upon the left side), these reflexes 
cannot be utriculus reflexes, as then the maximum positions would 
be the same. 
On the other hand, in the maximum and minimum positions of 
these reflexes the sacculus otolithes have again a very typical 
position; in the maximum position the sacculus otolith is hanging, 
whereas in the minimum position it presses. 
After a uni-lateral labyrinth extirpation the vertical deviation is 
maximal with the maximum position of the intact labyrinth, but 
with the minimum position it is very slight or absent. 
At all events it is certain that in the minimum position of the 
intact labyrinth there is no vertical deviation to the other side, from 
which we may fairly conclude that with the minimum position of the 
sacculus otolithes the stimulus is really little or none, whereas with 
the maximum position, on the other hand, it is very strong. 
Thus in this case also, as with the ‘‘Labyrinthstellreflexe’, it can 
be proved that the stimulus is strongest when the otolith hangs, and 
weakest or nothing at all when the otolith presses. 
