62 J. FRANK PEARCY AND THEODORE KOPPANYI. 



the fact as stated by Lee 3 that "the blinded fish swims normally 

 in all respects." 



Numerous experiments by Loeb, Bethe, Bigelow, Lee, Parker, 

 Maxwell, etc., have shown that the labyrinths are concerned with 

 the equilibrium of the fish. The orientation of fish deprived of 

 their labyrinths is very faulty or erratic. 



Comparing the striking effects on orientation of labyrinth 

 extirpation with the absence of effects from blinding appears to 

 indicate that the retinal image is not an important factor in 

 equilibrium and orientation in diffused light. 



The usual method of studying the influence of the eye on 

 orientation has been that of removal. The difference in the 

 animal's behavior before and after blinding has been interpreted 

 as being due to the removal of the visual function and therefore 

 it is to be considered as representing the normal effect of vision 

 upon orientation and locomotion. 



We attempted to approach the problem from a different angle. 

 We tried to investigate the role of vision in orientation not by 

 removal but by dislocation of the eye, hoping that while the 

 dislocated eye would still perform its visual function, the animal's 

 equilibrium and orientation could be observed and the problem, 

 whether or not the eyes influence orientation, put to a crucial 



test. 



EXPERIMENTAL. 



Large goldfish (Carassius auratus), eight and twelve inches in 

 length, were chosen for the work because of their availability and 

 especial suitability. 1 



The skull of the goldfish is high, forming a large intracranial 

 space over the brain which permitted the operative work to be 

 done readily. The method chosen was that of dislocation of one 

 eye and removing the other. Dislocation was performed by 

 inserting the eye with its nerve and blood supply intact into an 

 artificial orbit placed higher in the skull. This was accomplished 

 in the following way: 



A hole about the size of the eye was drilled in the top of the 

 head at a point in the vertical plane of the eyes just to the left of 



1 We acknowledge with pleasure our thanks to Mr. Parker and Mr. Young of the 

 Lincoln Park Zoological Gardens, who kindly supplied us with the fish used in this 

 experiment. 



