242 AYERS. [Vol. VI. 



tioned canal. Although hearing did not appear to be destroyed, 

 the locomotion of the birds was seriously impaired, and not in- 

 frequently indications of muscular paralysis made their appear- 

 ance. To Flourens the explanation, that these disturbances 

 were due to injury to the fibres of the nerve of hearing, was 

 not satisfactory, and he was led to the view that the cochlear 

 nerve was composed of two sorts of nerve fibres. One set 

 composing the cochlear nerve subserves the function of audi- 

 tion, while the other set composing the vestibular nerve sub- 

 serves the equilibrious function and is distributed to the semi- 

 circular canals. Injury to the former produced deafness, while 

 injury to, or destruction of, the latter was followed by the phe- 

 nomena described above. Similar results with more details 

 were obtained on repetition of these experiments and with some 

 variations of the conditions by Czermak, Harless, Brown-Sequard, 

 and Vulpian ; and although it was generally agreed that injury 

 to the semicircular canals of birds and mammals (the animals 

 mostly experimented on were Pigeons and Rabbits) or the ves- 

 tibular nerve was followed by disturbances resembling very 

 closely those following operations on the cerebellum ; and al- 

 though Flourens had advanced the view that the vestibular 

 nerve was the peripheral extension of the cerebellar peduncles, 

 these later observers did not agree with Flourens that the dis- 

 turbances following operatio7is for canal section were due solely, 

 or in great degree, to the section of the canals. Brown-Sequard 

 explained the phenomena by assuming the existence of special 

 sensory fibres in the vestibular nerve which by reflexes caused 

 the muscular contractions producing the motor disturbances. 



Vulpian, on the other hand, sought the cause of the trouble 

 in an "auditory tumult," caused by continued abnormal stimu- 

 lation or irritation of the auditory nerves. 



Loewenberg (1872, 186) experimented with Pigeons after re- 

 moving their forebrains, and concluded that section of the semi- 

 circular canals produced the motor disturbances by irritating 

 the membranous canals, not by laming their sense organs ; and 

 the disturbances were entirely reflex without the least participa- 

 tion of consciousness. 



Up to this time the subject had not been advanced beyond 

 the condition in which Flourens had left it ; but in 1870 Goltz 

 gave a new aspect to the problem by explaining the observed 



