428 



THE SENSORIAL FUNCTIONS. 



cular canals, but not extending into the cochlea. 

 These membranes, which compose what has 

 been termed, for the sake of distinction, the 

 memhranous labyrinth, form one continuous, but 

 closed sac, containing a fluid*, perfectly similar 



in appearance to the perilymph, which sur- 

 rounds it on the outer side, and intervenes be- 

 tween it and the sides of the osseous labyrinth, 

 preventing any contact with those sides. In 



* De Blainville has termed this fluid " la vitrine auditive," 

 from its supposed analogy to the vitreous humour of the eye. 



