22 ELEMENTS OF HISTOLOGY. [Chap. in. 



While fresh in contact with the membrane which 

 they line, or even after removal from it, provided 

 the cells are still alive, the ciliated cells show a rapid 

 synchronous whip-like movement of their cilia, the 

 cilia of all cells moving in the same direction. The 

 movement ceases on the death of the cell, but may 

 become slower and may cease owing to other causes 

 than death, such as coagulation of mucus on the 

 surface, want of sufficient oxygen, presence of car- 

 bonic acid, low temperature, &c. Under these circum- 

 stances, removal of the impediment will generally 

 restore the activity of the cilia. Moderate electric 

 currents and heat stimulate the movement, strong 

 electric currents and cold retard it. Reagents fatally 

 affecting cell protoplasm also stop permanently the 

 ciliary action. 



25. Oofolet or chalice cells (Figs. 13s, 16) are 

 cells of the shape of a conical chalice. The pointed part 

 is directed away from the free surface, 

 and contains a compressed triangular 

 nucleus, surrounded by a trace 

 of protoplasm. The body of the 

 ^^ contains mucus. This latter 

 may be in various states of forma- 



* 



the large intestine. out of the Cell. Goblet Cells are 



most commonly met with amongst 

 the epithelium lining the respiratory 

 organs, the surface of the stomach and 

 intestines, and especially in mucous glands, in whose 

 secreting portion all cells are goblet cells. 



The protoplasm of columnar cells facing a free 

 surface, no matter whether in simple or stratified 

 epithelium, ciliated or non-ciliated, may undergo 

 such alteration as will lead to the transforma- 

 tion of the cell into a goblet cell. This takes 

 place during life, and, in fact, represents an im- 



