1570 
oseillate between 0.15 and 0.48. This can neither be reasonably 
admitted. 
At last some doubt might rise with regard to the signification of 
this maximal excursion, as after all an isolated contraction of the m. 
obliq. sup. does not occur in the normal eye. I am however of 
opinion, that the knowledge of the maximal excursion can for all that 
give us an impression of the signification of this muscle for the 
normal motion of the eye. If we take moreover into consideration 
that, after having reached the tangential point through the point of 
insertion, the muscle operates so unfavourably, that we cannot 
expect such an inappropiate construction in the normal movements, 
than VoLKMANN’s calculations are by no means insignificant. 
Therefore I have calculated for the average eyes a and 5 the 
excursion that is required to bring the point of insertion into the 
tangential point. At the same time I have added hereto two cases 
g and / in the following way g: «2; as large as possible, y; as large 
as possible, 7 q average, consequently excursion as large as possible ; 
h: a; as small as possible, y; as small as possible, ”/ g average, 
consequently excursion as small as possible. 
The results were: 
For eye a: 4j=2.9 mm. yi=— 441 mm. vo 8.24 mm. maxim. excursion 22°27’ 
ms » 6: 4¢=2.9 mm. yi = —4.41 mm. / g = 471924’ 5 5 24° 8 
y nen te =D mm. yi 16.71 mm. fg = 471924 5 5 46° 9’ 
-s » AF to=05 mm. yi = — 1.71 mm. q —= 47°24" 5 ‘ 6°32’ 
The very important oscillations render it desirable in suitable 
cases of paralysis of the muscles of the eye to investigate this maxi- 
mal excursion more closely. In a case of oculomotorius paralysis 
from the clinic of Prof. WeRrTHEIM SALOMONSON | thought I might 
conelude from the field of vision, that this excursion amounted to 
sie". 
In the functions of the m. obliquus superior it is especially the 
position of the line of vision that requires our attention. The latter 
is however indicated by different authors in a widely different way, 
and it is therefore necessary that in the first place we agree how 
we shall indicate the position of the line of vision in our cases. 
Hermrorrz has indicated, that with erect head and looking forward 
in the distance the line of vision assumes a position nearly coin- 
ciding with the primary position of the eye, i.e. the position from 
which the eye moves in all directions without rotating round the 
line of vision, consequently according to the law of Listinc. The 
axes of motion are then always lying in a frontal plane, going 
through the center of rotation (plane of LisTIN@). 
