LABYRINTH AND EQUILIBRIUM. 



I. A Comparison of the Effect of Removal of the Otolith 

 Organs and of the Semicircular Canals. 



By S. S. maxwell. 



{From the Rudolph Spreckels Physiological Laboratory, University of California, 

 and the Marine Biological Laboratory, Woods Hole.) 



(Received for publication, September 16, 1919.) 



introduction. 



According to the conceptions of Mach and Breuer we must dis- 

 tinguish two kinds of equilibrial functions in the ear; the one, dynamic 

 through which movements of rotation are perceived, and the other, 

 static by which is produced a definite orientation or sensation of 

 position in relation to the lines of gravitational force. It was sug- 

 gested that the dynamic function is performed by the sensory struc- 

 tures of the semicircular canals, the static by the otoHth organs of the 

 vestibule. Although this view has been widely accepted the hterature 

 of the subject is full of contradictions and the experimental evidence 

 is far from satisfactory. 



Results of experiments on the labyrinth on which I have been 

 engaged for a long time show that no sharp differentiation exists 

 between the functions of the otolith organ of the utriculus and the 

 ampullae of the semicircular canals. I have found on the one hand 

 that a labyrinth from which the ampullae have been removed with- 

 out injury to the vestibular portions possesses both dynamic and 

 static functions, and that on the other hand a labyrinth from which 

 the otoHth organs have been removed without injury to the ampullae 

 retains both static and dynamic functions. 



The experiments reported in this article have been made on dog- 

 fish of the genera Mustelus and Squalus. The advantages of the dog- 

 fish as an experimental animal have often been pointed out. Among 

 these are the large size of the various parts of the labyrinth, the 



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