626 



this we may safely conclude that the phenomena, associated with 

 the irrigation, cannot be caused by an elimination of the labyrinth. 

 The objection that in these cases the unsatisfactory outcome of the 

 irrigation depended on mere chance, is refuted by the fact that 



1. irrigation was very effective before the extirpation of the 

 labyrinth 



2. irrigation after unilateral extirpation of the labyrinth in ventral 

 position actually arrested the spontaneous nystagmus and 



3. with head down the spontaneous nystagmus was not unaltered, 

 but was considerably stronger. 



Ad c. When, in one experiment, both labyrinths are removed, 

 violent movements are observable, but not nystagmus. If, however, 

 we first remove one labyrinth, the spontaneous nystagmus will be 

 seen to vanish after a short interval. Wheji subsequently the second 

 labyrinth is removed, nystagmus returns and that to the side of the 

 labyrinth that was first extirpated. We shall not enter into a 

 discussion here about the question how this nystagmus, fii'St described 

 by Bechterew '), is originated, and which parts of the central nervous 

 system come into play here for a nystagmus to manifest itself. This 

 is being further investigated at our institute. 



The time that has to elapse aftei' the first extirpation of a labyrinth 

 before a nystagmus can reveal itself after the second extirpation, 

 is varying, but after a few days it is sure to appear. 



If directly after the unilateral extirpation of the labyrinth water 

 is sent through the meatus on the unimpaired side, the spontaneous 

 nystagmus resulting from the unilaterar extirpation of the labyrinth 

 can be arrested in the ventral position by the irrigation as described 

 above. A repetition of this procedure at different intervals after the 

 extirpation of the labyrinth will prove that the spontaneous nystagmus 

 cannot only be arrested in a ventral position, but also that after 

 some time a nystagmus toward the opposite side is evolved by a 

 flow of water i e. towards the side of the first extirpation of the 

 labyrinth. In this phase we may look for the spontaneous nystagmus 

 detected by Bechterew, as quoted above, when the second labyrinth 

 has been removed. If, therefore, irrigation is identical with elimina- 

 tion of the labyrinth, then the latter compensation-nystagmus 

 must correspond entirely to the nystagmus obtained when some 

 days after the unilateral extirpation of the labyrinth, the meatus 

 of the unimpaired ear is irrigated. It appears, however, that 



1) Pflüger's Archiv Bd. 30 p. 312. 



