26 THE BIOLOGY OF THE CELL 



uncomfortable to the touch, and note the 

 changes taking place in the corpuscles. 

 Make drawings to illustrate the effect of the above 

 experiments. 



ExAMPLB 7. — Ciliated Cells 



Material. — "With a scalpel carefully scrape the roof 

 of the mouth of a recently killed frog, and mount the 

 scrapings on a slide in a drop of normal salt solution. 

 Some single cells and some groups will be found. It 

 may be necessary to use dilute iodine or one per cent, 

 acetic acid carmine to demonstrate some of the struct- 

 ures. Ciliated cells may also be obtained by tearing 

 into fine pieces the gills of a live clam. 



MOEPHOLOGT 



a. General Structure. — "What is the shape of a single 

 cell? How do you distinguish the upper end 

 from the base? Compare several as to shape. 

 Compare length with width. How are the cells 

 arranged? "What holds them together? Can 

 you distinguish a cell-wall? Protoplasm? Nu- 

 cleus? Contractile vacuole? On what part of 

 the cell are the cilia ? 

 Make drawings showing shape and structure of the 



cell. 



PHYSIOLOGY 



a. Movements. — "What part of the cell is capable of 

 movement ? Can the cell move as a whole ? If 

 so, by what means ? "What effect have heat and 

 cold upon the movements ? 



h. Ingestion. — Can the cell ingest particles of indigo ? 



