627 



there is not such marked concordance, as can be evidenced in the 

 following way : 



Of a cat the right labyrinth is extirpated ; a nystagnms occurs to 

 the left side. This nystagmus disappears after a few days. A flow 

 through the meatus of the unimpaired left side yields nystagmus to 

 the right side in ventral po.ntion ; but on changing the position of 

 the animal a change of the direction of the nystagmus is produced; 

 in a dorsal position e. g. it is always to the left. If on the same 

 day the left labyrinth is extirpated, the BECHTEREW-nystagmus to 

 the right side appears, whose dii-ection cannot be changed by 

 changing the position of the animal (nor indeed can its nature or 

 frequency). 



This, then, also proves that a flow of cold water cannot completely 

 arrest the function of the labyrinth. 



Ad d. If the function of the labyrinth were arrested by ejecting 

 cold water into the meatus, there could not be any vestibular reflexes 

 after ejecting it into the two meatus simultaneously. Rabbits are 

 highly serviceable for an inquiry into this matter, these animals 

 making hardly any spontaneous eye-movements, besides having very 

 strong eye-reflexes. We, therefore, experimented upon rabbits to see 

 whether after ejecting water into both ears rotatory movement or 

 deviation could be provoked through changing the animal's posi- 

 tion in space. From an investigation made by v. d. Hoeve and 

 DE Kleyn it appeared that in normal rabbits the greatest difference 

 in rotatory movement of the eyes may be observed, when first the 

 animal is examined with its head down and then with its head up. 



We subjected five rabbits to the following experimentation. 



First of all we ascertained whether no nystagmus at all was 

 discernible after water had been ejected into both ears. This was 

 necessary, as it was evident that with some animals the effect of 

 the irrigation is not quite the same on both sides, so that a slight 

 nystagmus still remains. Such animals were of course not suitable 

 for an investigation. When this inquiry had been made, a photo- 

 graph was taken of the head of the animal in two positions, with- 

 out irrigation, viz. 



animal vertical, head down 

 animal vertical, head up. 



In order to determine the intensity of the rotatory movement a 

 cross was burned into the cornea after cocainization. This, according 

 to VAN DER HoEVE and DE Kleyn's experience, somewhat slackened 

 the rotatory movement, so that it is somewhat less marked in our 

 experiments than is usually the case with normal rabbits. Consid- 



