42 THE BIOLOGY OF THE CELL 



damp bark, examine, and account for any differ- 

 ences you may find. 



Microscopic Characters : 



Examine first with a low, then with a high power 

 specimens prepared as directed. 



A. Vegetative Condition, 

 a. Arrangement. — Do you find groups of cells ? Single 

 cells ? What various numbers of individual cells 

 do you find constituting different groups ? Are 

 the cells arranged at all as in yeast ? 

 Draw single cells and groups. 



5. Shape. — What is the shape of a single cell? Is the 

 shape symmetrical or irregular ? Do you find any 

 noticeable variations ? How is the shape of the 

 individual cell modified where the cells occur in 

 groups? Compare the shape with that of the 

 yeast cell. Does it have a greater variety of 

 shapes than the latter ? How do you account for 

 them ? Does the cell have outgrowths or pro- 

 jections of any kind, such as roots? How does 

 green slime remain attached to the surface of the 

 bark or stone? Has it any organs of motion? 

 Does it resemble in shape any of the Protozoa ? 

 Draw several specimens showing marked variations 



from the normal shape. 



c. Size. — Do the cells vary much in size ? Measure sev- 



eral and find the average dimensions. How do 

 they compare in size with yeast ? With the slip- 

 per animal? With the red corpuscles of the 

 frog? 



d. Color. — What is the color as seen under the micro- 



