MECHANICS OF THE INNER EAR II 



Let us now consider another imaginary case which will 



contribute towards a better understanding- of the processes 



actually occurring in the ear. Suppose 



The effect of a a part of tlie tube " near the winclows > to 



rigid partition be divided by an inflexible partition, as 



within the tube shown in figure 5. It is self-evident that 

 in this case every movement of the stir- 

 rup would cause the particles of fluid in the upper and lower 

 division of the tube to move in the directions of the arrows, 

 parallel to the partition; and the particles at y. at the end of 

 the partition, to move up or down. But the fluid farther on 

 in the undivided tube would remain motionless, as in the 

 former case, since there is no sufficient cause why it should 

 move. If the partition extended farther, the only change re- 



_ 



Fig. 5. A rigid partition in the tube 



stilting would be a diminution of the length of that part of 

 the tube where the fluid remains permanently motionless. 

 If the partition extended to x (Fig. 5), leaving only a small 

 opening of communication between the upper and lower division, 

 all the fluid within the tube would have to move whenever 

 the stirrup moves. If the partition extended throughout the 

 tube, leaving no communication whatever between the two 

 divisions, no movement of the fluid could then take place, of 

 course; but no piston-like movement of the stirrup could 

 then take place either. 



