PARAM^CIUM. 



Paramcecium, as well as other ciliate protozoans, may be 

 obtained in the cultures prepared for obtaining Amoeba. They 

 may also be found in water in which hay has been allowed to 

 stand for about two weeks. These cultures should therefore 

 be prepared some time before the laboratory work upon them. 

 It is well, a day before use, to place some carmine powder in the 

 water. 



Take a drop or two of water on a slide, cover with a 

 cover-glass, and examine with a low power of the micro- 

 scope. If Paramcecia be present they will be seen as 

 small bodies swimming rapidly through the water. 

 Examine more carefully under a higher power and make 

 out the following points: 



The body is covered with innumerable fine hairs (cilia) 

 which are in constant motion. Are the cilia on all parts 

 of equal size? Does one end of the animal usually go 

 in front? On one side of the body is an opening (cytostome) 

 leading into the body. How are the cilia arranged with 

 reference to this? Follow the tube (cytopharynx) inward 

 from the cytostome. Where does it end? Is it ciliated 

 internally? In the protoplasm of the body can you dis- 

 tinguish ectosarc and endosarc (see p. 132)? Do you find 

 a contractile vacuole (p. 133) or more than one? What is 

 its shape at fullest extent (diastole) and at contraction 



(systole)? Draw weak acetic acid under the cover-glass. 



134 



