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, as by dilute 

 alkalies, 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. Goblet or chalice cells (Figs. 13B, 16) are 

 cells of the shape of a conical cup. 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 

 From aeni sec- goblet contains mucus. This latter 



tion through the may be in various states of forma- 

 tl] >ithelium on the . * 



surface of the mu- tion, and may at any tune be poured 



cous membrane of * n f^ 



the large intestine. Qllt OI the Cell. Goblet Cells are 



T ^^iu t K ^t s th^ir most commonly met with amongst 



cnunIry The co r htL^ 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 corresponds to an im- 



