CILIA. 
5 
sumed its erect condition, perhaps half a dozen of its suc- 
cessors are in diiferent degrees of flexure. This sort of 
motion will probably be better understood by referring to 
that beautiful and familiar spectacle, the waves produced 
by the breeze upon a field of standing corn. The motion 
is exactly the same in both cases. The wind, as it sweeps 
along, bends each stalk in turn, and each in turn reas- 
sumes its erect posture ; thus the wave runs steadily on, 
though the stalks of corn never remove from their place. 
The appearance of the ciliary wavo, when viewed under 
favourable circumstances with a good microscope, is so 
exquisitely charming, that even those who have been 
long familiar with it can scarcely ever behold it without 
admiration. 
