723 
horizontal plane) the direction is still the same; at 30° a slight 
deviation begins; at 50° it is much more pronounced. At 80° the 
direction of the nystagmus deviates as much as 135° from the initial 
position and at 100° the change of direction of the nystagmus of 
180° has been completed. Something like this occurs between the 
position of 170° and 270°. 
Observation left eye. Fundamentally the same as right eye. 
b. Rotation Ml. Douche of right ear. 
Observation left eye: A sudden change in the direction of the 
nystagmus takes place here between 140° and 150°. While the 
nystagmus at 140° moves posteriorly-upwards, at 150° it is already 
anteriorly upwards. A similar marked change of direction is observed 
between 310° and 320°, the direction being respectively anteriorly 
downwards and downwards. 
Observation right eye: Here it is less easy to say where the 
change of direction takes place. Presumably also between 140° and 
150° and between 300° and 330°. That in this case the curve differs 
from all the others may be explained by the fact that the process 
of the experiments averagely represented by this curve, was very 
irregular in two out of five cases, which could not but be of 
great influence on the mean curve. There was no such irregularity 
with the left eye of these animals (which was examined on another 
day). 
ce. Rotation LIL. Douche of the right ear. 
Observation left eye. Very great change of direction is found 
between 50° and 70° and a second change between 210° and 230°. 
Observation right eye. Very great change between 40° and 60° 
and a second between 220° and 240°. 
After the above facts had been ascertained, the critical point was 
Fig. 6. 
