Labyrinth and Semicircular Canals in the Human Ear, 251 



exhibited by the horizontal movement when the horizontal canal 

 on both sides was cut. The movement up and down was almost 

 continual : sometimes the head bent a little from one side to the 

 other, as if to make a turn half round (comme pour fair e un demi- 

 tour) ; but the dominant direction of the movement was always 

 from below upwards and vice versa. 



When the pigeon was stationary, its equilibrium was main- 

 tained ; and the better to preserve it, the animal rested its head 

 on the ground ; and it was always the top of the head bent 

 back (sommet de la tete renversee) which was so supported. 



The motion of the head always increased in activity along 

 with the other motions of the body, and, on the other hand, dis- 

 ordered the latter to such an extent that all regular movement 

 was impossible. 



In this experiment, unlike what occurred in the former when 

 the two horizontal canals were cut, the animal could neither 

 walk nor fly. When thrown into the air, after some incoherent 

 movements of its feet and wings, its whole frame stiffened, and 

 it fell like an inert mass. 



The animal never turned upon itself as when the hori- 

 zontal canals were cut ; but often, in its own despite, it fell over 

 backwards upon its tail, and sometimes rolled for a long time 

 in this direction. 



This pigeon was kept for nearly a year. It ate and drank vo- 

 luntarily (de lui-meme), although it had infinite difficulty in go- 

 verning its head for a moment so as to seize its food and drink. 

 It could never fly ; when it tried to walk at all fast, it fell and 

 rolled on its back. Almost always it remained in the same 

 place, the top of its head turned back resting on the ground or 

 against the bars of its cage. The vertical movement of the 

 head was always maintained, and always with almost equal in- 

 tensity. 



When the superior vertical canal on the left side of a third 

 pigeon was cut, there immediately resulted a slight but rapid 

 movement of the head from above downwards, and vice versa. 

 This movement was of short duration, but soon recurred. Left 

 to itself, the animal walked steadily or held itself erect ; though 

 liable from time to time to tumble forward. 



When the corresponding canal on the right side of the same 

 bird was cut, there instantly occurred a quick and violent move- 

 ment of the head from above downwards and vice versa. This 

 movement was accompanied, as in the former case, by disturb- 

 ance of equilibrium, which, in like manner, ceased when the 

 animal was in a state of repose, and recurred with its motion, 

 increasing in rapidity when the latter was accelerated. 



In all the experiments, when two corresponding canals were 



