124 ILLINOIS ACADEMY OF SCIENCE 



left and of a sudden jerk back to tlie original position, 

 bore a definite relation to tlie direction of the theoretical 

 flow of licpid in the canals. 



About 1906 Eobert Barany of Vienna recogiiized the 

 possible clinical significance of this close relation be- 

 tween the semicircular canals and the eyes and he began, 

 therefore, a series of investigations in the clinical labora- 

 tory based upon the work that had already been done. 

 The outcome was a series of tests for the determination 

 of vestibular "normality". The regularity with which 

 the ocular effects usually appear, together with a neuro- 

 logical doctrine based upon investigations of Cajal and 

 Golgi and worked out more in detail for clinical purposes 

 by Hoyges and Euttin, suggested the assumption that 

 nj^stagmus was a simple and invariable reflex response 

 to the excitation of the canals and that its appearance 

 could be used as an index of the normal or of the patho- 

 logical condition of the nerve tracts leading from the 

 canals through the cerebellum to the ocular muscles. 

 Some of these tests, which have come to be known as the 

 Barany tests, rest essentially upon the supposition that 

 n^^stagmus is always a reliable index of the functional 

 integrity of the neural pathways concerned. 



It thus came about that during the war a small group 

 of American otologists appropriated the results obtained 

 by Barany and made out of them a series of tests for 

 use in the Air Service of the Army. The nystagmus test 

 was confessedly based upon the assumption that the ocu- 

 lar movements following rotation were simple reflexes 

 comparable in every respect to other well-known re- 

 flexes. But while investigating the matter at the Mineola 

 Laboratory, the psychological department found reason 

 to question the simplicity of these ocular responses and 

 after a series of investigations Bentley and others came 

 to the conclusion that these effects were not a reliable 

 index of function of the semicircular canals, in as much 

 as they were discovered to be profoundly influenced by 

 practice.* For instance, it was determined that nystag- 

 mus might be made to disappear altogether under 



■•See Manual, Medical Research Laboratory, 1918, pp. 186-193. 



