CHAPTER X 



PHYLUM I. PROTOZOA (Primitive Animals) 



LABORATORY EXERCISES 



Without compound microscopes this branch of animals can- 

 not be studied with profit in the laboratory. The Amoeba is 

 one of the most interesting of the Protozoa and serves well to 

 illustrate the simplest forms of animal life, but large specimens 

 in sufficient numbers for profitable study in an elementary class 

 are usually so difficult to secure at the right time that it be- 

 comes a question whether the teacher should be advised to 

 depend on them. My advice is, make every arrangement you 

 can to secure them, use them for demonstration or study 

 whenever they appear, but depend on Paramecium. Perhaps 

 the surest method for securing Amoeba is to chop up the soft 

 parts of three or four fresh-water mussels, placing the pieces, 

 together with the shells, in a large shallow basin. Allow a 

 gentle stream of water to drip into this. This keeps the water 

 slightly agitated, causes it to run over, and prevents an undue 

 accumulation of bacteria. The addition of a little of the sur- 

 face mud secured from the bottom of several streams or ponds 

 will make the success of the preparation all the surer. Amcebas 

 should appear at the surface of the mud, about the shells, 

 or at the margins of the vessel near the surface of the water. 

 Test all these places every day, and sooner or later the amoebas 

 are practically sure to be found. Paramecia will be likely 

 to occur in the same preparation. Any abundant Protozoan 

 which may appear may be studied instead of Paramecium or 

 in addition to it, by means of the outline below. The mode 

 of securing the materials should be explained to the class to 

 make clearer the habits of these organisms. 



190. Paramecium. This protozoan may be obtained 

 readily by allowing fresh- water algae, with hay or leaves, to 



149 



