38 



MANUAL OF PHYSIOLOGY. 



modified in different ways, so as to suit it for the special part in 

 which it is placed. Some tracts are covered with fine moving 



FIG. 11. 



FIG. 11. Two cells of scaly epithelium from the inside of the cheek. 

 (Kanvier.) 



FIG. 12. Section of milk gland of cat, showing secreting cells containing 

 fat globules, and some secretion in alveoli. 



hair-like processes, called cilia, which give rise to a slight motion 

 of the fluids in contact with them. 



FIG. 13. 



FIG. 14. 



FlO, !'{. Ciliated epithelial cells from tin- .yills <>f mussel. (Cadiat.) 

 FIG. 14. Stratified ciliated epithelial cells from the trachea of man. 

 (Cadi.-it.) a. Lnr^e surface cells, with cilia on surface. 6. Lower cells in 

 earlier stage of development, c. Cell charged with mucus. 



Other differences will be given in detail with the description of 

 the duties of the many mucous surfaces. The most striking, and 



