521 
y. When the trunk is turned on its dorso-ventral axis, through 
movements in the direction of the palpebral aperture, in which 
process the eye towards which the trunk is turned moves towards 
the nose, the other eye towards the ear. 
These compensatory eye-positions in the direction of the palbebral 
aperture could be shown only for the cervical reflexes and not for 
the labyrinth reflexes. 
7. The fact discovered by Barany in 1907 that in normal rabbits 
the eye-positions, occurring with a change of the position of the 
trunk relative to the head, vary with the position of the trunk in 
space may be ascribed to a superposition of tonic labyrinth-, and 
cervical reflexes appearing in BARANY’S experiments. 
8. In some rabbits the centripetal fibers for the reflex arch of the 
tonic cervical reflexes pass only through the sensitive roots of the 
Nn. cervicalis 1 and 2. In others also the sensitive roots of the 
Nn. cervicalis 3 exert some influence. 
9. With tonic cervical reflexes the eye-muscles are affected by a 
reciprocal innervation. This was observed for the M. Rectus internus 
and externus, when the trunk was turned on its dorso-ventral axis 
with the head fixed. Also the purely tonic character of the cervical 
reflexes is distinctly demonstrable here. 
10. It holds in general for the tonic labyrinth-, as well as for 
the tonic cervical reflexes that, when the position of the head relative 
to the trunk is changed, the eyes perform such movements in order 
to attain their new position in the orbita that they try, as it were, to 
retain their position in space. However this position is not attained 
either by the tonic labyrinth or by the tonic cervical reflexes alone. 
The effect of the combinations of the two kinds of reflexes, however, 
is that the rabbit can bring its head from its normal position (head 
lowered about 35° under the horizontal) into every position by raising 
or lowering its head within wide limits. This it can do without 
change of the position of its eyes in space, consequently without any 
alteration of the field of vision. 
Pharmacological Institute of the Utrecht University. 
