STUDIES IN ANIMAL LIFE. 

 Fig. 2. 



17 



GEOTIP OP VOBTICELLA NEBUIJFEKA on a Stem of Weed, magnified. 



A, one undergoing spontaneous division ; B, another spirally retracted on its 

 stalk ; C, one with cilia refracted ; D, a bud detached and swimming free. 



membrane of your air-passages is covered with cilia, 

 which may be observed by following the directions 

 of Professor Sharpey, to whom science is indebted 

 for a very exhaustive description of these organs. 

 " To see them in motion, a portion of the ciliated 

 mucous membrane may be taken from a recently- 

 killed quadruped. The piece of membrane is to be 

 folded with its free, or ciliated surface outward, 

 placed on a slip of glass, with a little water or serum 

 of blood, and covered with thin glass or mica. 

 When it is now viewed with a power of 200 diam- 



