10 



OF MC.<CI.I:S AM> N 



7. If ;i light powder such. for in>t;iiifr. ;is finely 

 powdered charcoal is spread over the skin of the 

 palate of a living or a recently killed fn>g, the pn\\der 

 is seen to advance with some speed inwards the gullet. 

 Microscopic examination shows thai this >kin is studded 

 with a dense layer of cylindrical cells standing, palisade- 

 like. side liy side. The free surface of each of these 

 cells is studded with a large number <>{ delicate hairs 



a 



a. Ciliatnl roll>, 



:ill(l. With 



:iti:n-hi-i| In tliL- iin-iii 



brane. 



Fi... ::. 



!- b. A 



riliutc'l cell. 

 .I and 

 wlmt mop uii^liiiL-.l form. 



or cilia 1 , which are in cnut iniial motion in a definite 

 direction in >nch a way that they propel all such liquid, 

 together with <he ]i:irt ides contained in this, as adheres 

 to (heir upper surface in that direction. This is called 

 ciliarv motion. It occurs very frequently in t lie animal 

 liody. e.<r. iii the windpipe and its branches where the 

 motion is upward, serving to propel the phlegm to the 

 lar\n\, from which it can be thrown out by coughing. 



