PROTOCOCCUS VIRIDIS. 23 



quite as well as any to illustrate the simplest kind of 

 plant life. 



To complete the following study it will be necessary 

 to have pieces of wood bearing the Protococcus ; iodine ; 

 chlor-iodide of zinc ; and alcohol. 



LABORATORY WORK. 



GROSS ANATOMY. 



Taking either a fresh or dried specimen, notice 



1. The color. 



2. The evenness with which the plant overspreads the 

 supporting surface. 



Using a lens, notice 



3. The pulverulent appearance, as if dusted or sanded 

 upon the surface. 



4. The appreciable thickness reached in some spots, 

 causing it to separate in scales in the dried specimen. 



Mount, and observe 



5. The dust-like particles' 1 into which it separates. 



6. The varying size of the particles. 



Place a piece of bark with the Protococcus in a small 

 quantity of alcohol, after an hour or more notice 



7. The color imparted to the alcohol by the coloring 

 matter of the plant, the chlorophyll. 3 



MINUTE ANATOMY. 



Under high power, notice 



8 Care must be taken not to confound them with air bubbles, which 

 are often numerous when a dried specimen is used. 



8 Some less common forms of unicellular algae are red or purple from 

 additional coloring matter. 



