APPENDIX D 



PREPARATION OF MICROSCOPICAL MATERIAL FOR A 

 GENERAL COURSE IN ZOOLOGY 



(In addition to the methods enumerated here, see also chap, x, II and 

 chap, xiii.) 



PROTOZOA 



a) Cultures. Amebae, etc., may usually be obtained in quan- 

 tities sufficient for class use by the following method recommended 

 by H. S. Jennings: 



A number of glass dishes measuring 8 or 9 inches in diameter 

 by 3 inches deep are crowded full of water plants (especially 

 Ceratophyllum and Elodea), filled with water, and the plants 

 allowed to decay. Keep the dishes in warm, light places. In 

 two or three weeks the layers of plants at the surface of the water 

 will be covered with a brown slime which should be examined 

 occasionally under the microscope for the desired forms. The 

 scum that appears on the surface of the water consists mainly of 

 bacteria upon which amebae largely feed. They will be found 

 most frequently in the slime that immediately surrounds the plant 

 tissue. Since they frequently last only two or three days in a 

 culture, to insure material for class work, a number of cultures 

 must be made at different dates and from different localities. 

 Other protozoa such as Arcella, Difflugia, Carchesium, Stenior, 

 etc., will also be found in the cultures. 



Paramoecium may be kept from dying out by keeping bits of 

 stale bread in cultures. 



Euglena will be found in some 'of the cultures, but usually not 

 in any quantities before the end of four or five weeks. They 

 appear along the side of the dish toward the light. 



Carchesium and Vorticella are frequently found on decaying 

 duckweed (Lemna) and horn wort (Ceratophyllum). To secure a 

 culture, have a more plentiful supply of water than for ameba. 

 Professor Walton tells me that he always finds a supply of 

 Epistylis on the shells of fresh water snails. 



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