'i 4 ELEMENTARY BIOLOGY. [CHAP. 



LABORATORY WORK. 

 A. MORPHOLOGY. 



a. Resting or stationary Protococcus. 



1. Spread out in water some mud from a gutter or 

 similar locality, and put on a cover-glass. Look for 

 the red or green protococcus cells with a low 

 power. Having found some, put on a high power 

 and make out the following points. 



Size; (measure) very variable. 



Form; more or less spheroidal, with individual 

 variations. 



Structure; sac protoplasm sometimes a vacuole 

 sometimes apparently a nucleus. (Compare 

 Torula, I. A. 2. b.) 



Colour; generally green sometimes red sometimes 

 half and half sometimes centre red, periphery 

 green the colouring matter always in the pro- 

 toplasm only most frequently diffused, but 

 sometimes in distinct granules, or oily looking 

 drops. 



2. Note especially the following forms of cell 

 a. The primitive or normal form. 



Roundish cells, with a cellulose sac, and unseg- 

 mented granular contents. Draw several carefully 

 to scale. Apply the methods of mechanical and 

 chemical analysis detailed for Torula. (I. A. 3. 4. 

 5. 6.) Note that iodine in some cells produces a 

 blue coloration by its action on the red matter 

 present. Treat a specimen with strong iodine 

 solution and then with sulphuric acid (75 per 

 cent.) : the sac will become stained blue. 



