749 
to its original position. Then the last determination served for a 
eontrol-estimation. A short interval after every rotation of 10° was 
required before each reading, to preclude the possibility of a nystagmus, 
resp. deviation brought about by the rotation itself. 
The irrigation of the right meatus took place from a height of 
1,5 m., the cold-water used was of a temperature of + 12° C. 
For every position in space, after it had continued for some time, 
the direction of the nystagmus was valued and the direction of the 
rapid component was marked down. (Figs 2, 3, and 4 not corrected). 
This method does not yield perfectly reliable data; for a correct 
determination of the direction one might resort to cinematographic 
photos from which to decide on the direction. However, this was 
impracticable for a large number of determinations. Still, from what 
follows here we may infer that our method of valuation of the 
direction of the nystagmus yielded useful results. 
In figs. 2—4 
— = Direction of the quick component of the nyst. towards the nose 
== ” np > 52 » », towards the temporal 
t= » 5 9 A » », upwards relativeto the 
orbita. 
== ys 35 Pb 95 55 » » downwards. 
Fig. 2—4 (not corrected) gives the mean of 5 experiments. 
Now, however, the question rises: what influence is exerted on 
the nystagmus by the above-mentioned tonic eye-reflexes, occurring 
in the eye-muscles (compensatory eye-positions) with different positions 
of the head in space. On p. 246 of V. p. Horvw’s research, mentioned 
above, a curve is given of the rotatory movements. 
With the aid of this curve the directions of the caloric nystagmus 
found, were now corrected as follows 
We assume that douching with cold water, with the head in 
normal position, engenders an absolutely horizontal nystagmus with 
the quick component towards the nose. Now, when the position of 
the head changes from the normal into another position in space, 
so that a rotatory movement of the eyes ensues, e.g. of 45° with 
the upper cornea-pole towards the temporal, the insertion-points of 
the eye-muscles, notably of the Mm. internus and externus, will 
also be changed by this rotatory movement, and the same contrac- 
tions and relaxations of these two eye-museles, which caused with 
the normal position an horizontal nystagmus, will bring about a 
nystagmus of quite a different direction, viz. about 45° anteriorly 
upwards. 
So for instance if an horizontal nystagmus appears at the normal 
