A. THE STUDY Of LIVING CELLS. 



For convenience of study, cells may be classified as to manner 

 of association as follows: 



1. Those which live separate from one another. Examples, 

 Unicellular Fungi and Algae, Pollen-grains, Spores, etc. 



II. Those living in Colonies, i. e., joined temporarily, but 

 which are able to perform all their normal functions if isolated; 

 example, Spirogyra, (known as "Frog-Spawn," "Water-Carpet," 

 "Pond-Scum," etc.) 



III. Those which live permanently joined to other cells and 

 which cannot ordinarily perform their normal functions if isolated; 

 (a) they may not form Tissue ; example, Nitella ; (b) they may 

 form Tissue- example, Roots, Stems, Leaves of Flowering l^lants. 



CASE I. 



Isolated Cells Containing Protoplasm. 



Illustration: Protococcus viridis, Ag. (green slime.) 

 The plant can be found in damp places, growing on the bark 

 of trees, or in the corner of buildings on the brick, or stones of the 

 foundation. In fact so general is the plant distributed that no one 

 need have any difficulty in getting material in good condition for 

 study. 



PREPARATION FIRST : With a knife remove some of the material 

 from the substratum and mount in water. Place under the high 

 power of the microscope and OBSERVE: 1. The unicellular plants, 

 often associated in group*. 



2. Their size, shape, and general appearance. 



