54 THE BIOLOGY OF THE CELL 



do you account for the slippery feel of the 

 plant ? 



c. The structure of the individual cell. 



1. The cell--wall. — What is the shape of the side- 



wall ? Of the end- wall ? What is the color of 

 the cell-wall ? Which is the thicker, the side- 

 wall or the end-wall ? Do you find any open- 

 ings in either wall ? Markings of any kind on 

 the wall ? Eun a drop of strong iodine under 

 the cover-glass, then a drop of seventy-five per 

 cent, solution of sulphuric acid, and note the 

 effect upon the cell -wall. Of what is it com- 

 posed ? Try also Schulze's solution. Treat a 

 fresh preparation with strong potash solution, 

 and note the stratification of the wall. How do 

 you account for this appearance ? 

 Take another fresh preparation and examine 



2. The chromatopliores or chlorophyll bodies. 



— What is their arrangement ? General shape \ 

 What is the shape of their margins ? How many 

 in a cell ? How many turns does each make % 

 In what part of the cell do they lie ? Do they 

 extend from one cell into the next? What 

 is their color? Are there any other colored 

 bodies in the cell ? Do these chromatophores 

 in any way resemble the green part of the cell 

 of Protoooccus ? To what is due the color of 

 the plant as a whole? What significance in 

 the scientific name of the plant ? Put some 

 filaments into strong alcohol and examine 

 them after a few hours. What change in the 

 chromatophores? In the alcohol? Explain. 

 Stain some of the filaments with carmine or 



