518 
Afterwards the sensitive roots of the Nn. cervicalis 1 and 2 were 
severed on both sides. 
Head vertically upwards. Head vertically upwards. 
o 10 20 30 40 50° 69 0 10 20 30 40 50 60 
Rotation 
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Rotation 
Os 10 20 35, Gok So) 60) | 0 0 10 20 30 40 50 60 70 
Head vertically downwards Head vertically downwards. 
Fig. 3. 
Fig. 3b shows that at the raising and the lowering of the head 
the rotations are approximately equal to those determined for the 
labyrinth reflexes alone. The hatched part of the curve (cervical 
reflexes), however, has not completely disappeared, so that also with 
this animal the Nn cerv. 3 still play a very weak part in the 
cervical reflexes. 
Let us look at Fig. 3a more closely : | 
Commencement of the experiment: 0°: animal in ventral position, 
mouth fissure horizontal. Lowering of the head: 
10° lowering of the head; rotation 10° 
20 9 Ee it ct 20° ete. 
70° B % Á % 70 
We see from this that when the head is lowered down to 70° below 
the horizontal, the position of the eye in space remains absolutely 
constant, the eye performs a rotation (with the upper pole in the 
direction of the ear) of as many degrees as the head is lowered 
under the horizontal. 
Raising of the head: 
10° raising; rotation 10° 
20° 1 ns PS? rete, 
60° + od 37° 
