PARAMECIUM 1 



1. Mount a drop of water containing Paramecia, together with a little 

 powdered carmine, and examine with the low power. The animals will be 

 seen as light-colored, rapidly-moving bodies which rotate on their long 

 axis as they swim. With the naked eye, the Paramecia are just barely 

 visible as tiny white specks. 



2. Select a quiet animal under the low power and then study with the 

 high power. 2 Distinguish the anterior and posterior ends. Note: 

 (a) the clear outer ectoplasm with pellicle; (b) the granular, inner 

 endoplasm; (c) the fine, vibratile cilia which cover the entire body; 

 (d) the depression (peristome) which begins at the anterior end and 

 extends obliquely backward to beyond the middle of the body ; (e) the 

 mouth, located near the posterior end of the peristome ; (/) the funnel-like 

 depression (gullet) which leads from the mouth down into the endoplasm ; 

 (g) the position and rhythmic appearance and disappearance of the two 

 contractile vacuoles with their radiating canals. Focus carefully 

 on the edge of the body and note (h) the layer of tiny oval bodies (tri- 

 chocysts) lying in the ectoplasm just beneath the outer surface. 



3. Observe that the current caused by the ciliary action sweeps the 

 carmine particles, which were placed in the drop of water, down the peri- 

 stome, through the mouth opening and into the gullet, at the lower end of 

 which they collect in a gastric vacuole. Note the numerous gastric 

 vacuoles containing the carmine particles in the endoplasm. 



4. Make a drawing about 3 inches long showing the structures observed. 



5. Remove the cover glass of the preparation you have been studying 

 and add a drop or two of acetic carmine. This will kill the animals and also 

 stain the nuclear apparatus (macronucleus and micronucleus). Study 

 with the high power and add the details of nuclear structure to your draw- 

 ing in paragraph 4. 



6. Place a drop of water containing Paramecia on a clean slide and kill 

 the animals by adding a drop or two of iodin solution. Note what happens 

 to the cilia and trichocysts. Make a drawing of a small portion of the 

 ectoplasm showing some of the trichocysts with the threads protruded. 



7. Make a fresh preparation of the Paramecia and draw any animals you 

 see which may be undergoing rinary fission or conjugation. 



1 B. pp. 39-47. 



2 It will probably be necessary to remove the cover glass and add a drop or two 

 of quince-seed jelly to the preparation in order to quiet the animals. 



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