914 
3. Compensatory positions of the eyeball. 
a. The vertical deviations are sacculus reflexes and are caused 
by the main portion of the sacculus macula. One sacculus macula 
is connected with the rectus sup. of the same side and with the 
rectus inf. of the crossed side. 
b. The rotatory deviations are probably produced in the sacculus 
corners, which have their own innervation. 
Stimuli proceed constantly from the maculae and do not alter as 
long as the otolithes do not alter their position with respect to the 
horizontal plane. When the otolith stands horizontally, the strongest 
or the weakest stimuli are excited.- 
In the case of the sacculus otolithes it can, with respect to the 
“Labyrinthstellreflexe’” and of the vertical compensatory deviations 
of the eyes, be proved with certainty, that the strongest stimulus 
occurs when the otolith is hanging. 
For the sacculus corners, on the contrary, things are somewhat 
more complicated, and the stinuli occur when the otolithes press 
as well as when they hang. 
As our investigation is at present concerned with the rabbit, the 
above holds good only for this species. 
B. Isolated removal of the otolithes in guinea-pigs. 
As has appeared from this and former communications, the dif- 
ferent labyrinth reflexes may be divided into the following groups. 
a. Reflexes upon movement. 
1. Reactions and after-reactions of ‘the head and eyes upon 
rotatory movements. 
2. Reactions upon progressive movements. 
b. Tome labyrinth reflexes. 
1. Tonic reflexes upon the muscles of the body. 
2. “Labyrinthstellreflexe’’. 
3. Compensatory positions of the eyeball. 
As regards the reactions and after-reactions upon rotatory move- 
ments, these have long been known and are justly regarded by all 
researchers as reflexes, of the semi-circular canals. 
It was demonstrated above that the different tonic labyrinth reflexes 
are probably otolith reflexes, and also that different otolithes may 
be held responsible for the different reflexes. 
But little experimental research has hitherto been devoted to the reactions 
upon progressive movements. For some classes of animals, however, we were 
able to demonstrate certain reactions upon progressive movements dependent 
on the labyrinths. As the following investigations have been carried out 
