gmatism, is
offset by this: that the oval pupil functions as a stenopaic slit.
In view of the width of the horse's pupil this appears to me to be
rather hypothetical.

Concerning Berlin's theory of deflecting astigmatism I would say the
following: Of the two ophthalmoscopic signs mentioned as being
characteristic of this form of astigmatism,--the concentric circles
and the arcuate deflection of the pathway of the fixated
points,--when there is a movement of the eye of the observer (or of
the eye observed), according to Berlin the former is not so constant
as the latter. So far as I know, the concentric ring formation is
mentioned only by Bayer[47] and Riegel,[48] and is said to occur
principally in horses with myopic vision--and hence, relatively, in
a minority of cases. Judging from the particulars, we are inclined
to believe that a case of "Butzenscheiben"-lens reported by
Schwendimann[48_a_] is in reality a case of senile sclerosis.
Berlin repeatedly warns us against mistaking the one for the
other.[48_b_] The arcuate deflection, on the other hand, has not
been mentioned elsewhere as a personal observation. In Berlin's
calculation[49] of the increase in the extent of the retinal pathway
an ambiguity has crept in. He says that "in the astigmatic eye there
are stimulated 207 times as many nervous elements as would be
stimulated in the ideally normal eye." It ought to read "207 more"
instead of "207 times as many." And this number holds only for the
one case computed by Berlin, and under the specific assumption that
exactly [Greek: pi]/2 times the normal number of elements were
stimulated (571 instead of 364). Therefore the general statement
which Bayer[50] makes in his text-book, that according to Berlin's
evaluation "207 times more nervous elements" are stimulated in the
astigmatic eye than in the non-astigmatic one, does not hold true.

Closing this note, a few remarks concerning the experiments made by
Dr. Simon and myself. All of the nine horses were tested for the
vertical image by means of the ophthalmoscope. In most cases Wolff's
electric speculum was used. Atropine was not employed.--For the
laboratory tests the adipose and the muscular tissues were removed
from the eye-ball and the rear part of the bulb cut away. The front
part, containing the cornea and the lens, was