Physiology". — "Concerning Vestibular Eye-refie.ves." By Mr. 

 A. DE Kleyn and Mr. W. Storm van Leeuwen. I. "On the 

 Origin of Caloric Nystagmus" (Communicated by Prof. H. 

 Zwaakdemaker). 



(Communicated in the meeting of June 30, 1917 ) 



Altlioiigli it has long been a matter of common knowledge that 

 a nj'stagnms is induced by allowing cold or warm water to flow 

 into one ear, and this has been the subject of a considerable amount 

 of experiments with men as well as with animals, the origin of 

 this caloric nystagmus is still a moot point. 



Among the various views taken of the subject those of Barany 

 and Bartels stand prominent. 



Barany holds that streams in the endolymph evolved by a change 

 of temperature excite the coloric nystagmus, whereas Bartels inclines 

 to believe that by applying cold water the function of the labyrinth 

 is eliminated entirely or in part and that by applying wai:m water 

 the labyrinth is stimulated. 



It being our purpose to endeavour to clarify our ideas concerning 

 the cause of the caloric nystagmus, we first of all made a series of 

 experiments to ascertain whether the caloric nystagmus may perhaps 

 be provoked by arresting the function of the labyrinth through cold 

 water. The results of this inquiry will be discussed in this paper. 



In our investigation we started from the following considerations: 



If the caloric nystagmus is brought about by eliminating the 

 labyrinth on the irrigated side, the caloric nystagmus must present 

 the phenomena resulting from an extirpation of the labyrinth. 



These phenomena are : 



a. The caloric nystagmus would correspond in direction, frequency 

 and nature, exactly with the spontaneous nystagmus occurring after 

 extirpation of the labyrinth. 



b. It would be possible to arrest the nystagmus, occurring directly 

 after extirpation of a labyrinth by ejecting cold water into the other 

 labyrinth. 



c. When in an animal one labyrinth has been extirpated, a 

 spontaneous nystagmus will ensue, which will disappear again after 

 some time; the nystagmus is then what is termed "compensated". 



