717 
The result of a similar investigation carried on') together with 
Prof. Maenus, was published in GrarFm’s Archiv., and led to the 
following conclusion : 
“Bei Katzen, bei denen die Sympathicusbahnen zum Auge durch 
das Mittelohr verlaufen, tritt bei Ausspritzen des äusseren Gehör- 
ganges mit kaltem Wasser eine Sympathicuslähmung am Auge auf, 
die sich vor allem im Vortreten der Nickhaut äussert. Sie beruht 
auf einer Kalteparese der genannten Bahnen. Dadurch ist der Beweis 
geliefert dass beim Auslösen des kalorischen Nystagmus mit kaltem 
Wasser die Wand des Mittelohres über dem Labyrinth sich nach- 
weisbar abkiihlt.” 
We now pass on to report the results of our new experiments 
on the cold-water nystagmus in rabbits. 
Our reason for selecting rabbits, while our previous experiments 
were chiefly carried out with cats, is the following: 
First, in rabbits we seldom meet with rotatory nystagmus, of 
which the direction is always difficult to indicate. It is encountered 
in cats. The principal reason, however, is that in our experimenta- 
tion we made use of an inquiry into the compensatory eye-positions, 
which have been carefully determined for the rabbit in conjunction 
with v. p. Hoevr*), but are difficult of determination for the cat. 
Technique of our method. 
A rabbit was suspended on an operation-board, and the head fixed 
firmly in a Czermak-clamp. Now in order to be able to bring the 
animal in any given position in space, the following contrivance 
was made (Fig. 1). The operation-board p-q-r-s is fixed to a wooden 
frame P-Q-R-S in such a way that the board p-q-r-s can rotate on 
the axis U-T, while the frame P-Q-R-S is again fixed to a second 
frame A-B-C-D, so that both P-Q-R-S and p-q-r-s can rotate on the 
axis V-W. A protractor is attached to P-Q-R-S, as well as to A-B-C-D, 
so that the degree of the rotation can be noted exactly in every 
direction. Now when the animal has been tied to the board in 
ventral position, a rotation on the axis V-W causes the animal to 
rotate on its bi-temporal axis. When moving the board round the 
axis U-T the animal turns on its occipito-caudal axis. When finally 
1) A. pe Krein und R. Maanus. Sympathicuslähmung durch Abkühlung des 
Mittelohres beim Ausspritzen des Gehörganges der Katze mit kaltem Wasser. 
Graefe's Archiv Bd. 96. (1918) 5, 368. 
4) J. v. p. Hoeve und A. pe Kreis. Tonische Labyrinthreflexe auf die Augen. 
Pflúg. Arch. Bd, 169. (1917) S. 241. 
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