Physiology. — ‘“Hwperiments on the Quick component Phase of 
Vestibular Nystagmus in the Rabbit’. By A. pr Kueyn. 
(Communicated by Prof. R. Maenus). 
(Communicated at the meeting of March 26, 1921). 
When cold water is allowed to run into the right external audi- 
tory ‘canal, a nystagmus will appear whose immediate effect is a 
slow deviation of both eyes towards the syringed, ergo the right side. 
This deviation is succeeded by a quick movement of the two 
eyes towards the non-syringed, i.e. the left side. Then again follows 
the slow deviation to the right. These alternations of slow-, and 
quick eye-movements will recur while the syringing continues, and 
for some time after. 
With every vestibular nystagmus the primary deflection is such 
a slow deviation, the so-called slow component phase of the nystag- 
mus; the rapid movement, the so-called quick component phase is 
secondary. 
It would be reasonable therefore to determine the direction of a 
nystagmus by the direction of the slow component phase. However, 
the quick eye-movements strike the observer more particularly, so 
that what in the clinical and in the physiological literature is called 
a nystagmus to the right is almost exclusively a nystagmus in which 
the quick component phase: moves to the right; whereas by a 
nystagmus to the left a nystagmus is meant in which the quick 
component phase moves to the left. Although in strictness this does 
not square with the theory, from a practical point of view it will 
be well to adhere to this conception. 
All researchers agree that the slow component phase arises from 
a direct reflex from the labyrinth via the nucleus of the N. vestibu- 
laris to the nuclei of the eye-muscle and the eye-muscles. As regards 
the origin of the quick component phase, opinions differ widely. 
Hardly any experiments have been made, so that we possess only 
a large number of more or less probable theoretical speculations and 
are still left much in the dark. 
We have no intention to discuss these several theories. Only one 
of them, viz. Bartets’ theory, we will test experimentally. BARTELS 
assumes that the source of the reflex that gives rise to the quick 
