THE LABYRINTHINE SENSATIONS 677 



of the vestibule and semicircular canals left the auditory sense intact, 

 but caused marked disorders of equilibration. That the peculiar 

 arrangement of the semicircular canals in the three planes of space 

 was connected in some way with the functions of these structures 

 was also indicated by Flourens' observation that destruction of the 

 horizontal canals on each side gave rise to continual nodding move- 

 ments of the head in the plane of the injured canals. By many 

 physiologists the results obtained by Flourens were ascribed to 



FIG. 311. End -organ of vestibular nerve in ampulla of semicircular canal 

 (' crista acustica ' ). 



continued irritation of the peripheral sense-organs or of the central 

 parts of the brain in consequence of the lesion. The accurate experi- 

 ments of Goltz, and especially those of his pupil Ewald, showed 

 that these effects might last twelve to eighteen months, or be per- 

 manent, and must therefore be regarded as an Ausfallserscheinung, 

 i.e. as due to abolition of a function and not to the arousing of a 

 function by abnormal stimulation. 



Most of the experiments on this subject have been carried out on 

 pigeons on account of the easy accessibility of their semicircular canals. 

 Confirmatory observations have, however, been made on mammals. 

 After destruction of all the canals or of the whole membranous 

 labyrinth on both sides, disturbances of equilibrium are aroused 



