APPENDIX 



COLLECTION, CULTIVATION, AND OBSERVATION 

 OF PROTOZOA 



Collection 



IN THE FOREGOING chapters it has been pointed out that the 

 various species of Protozoa have characteristic habitats and 

 that many of the free-living forms are widely distributed in 

 bodies of water: fresh, brackish, and salt; while the parasitic 

 forms are limited to specific host organisms. Of the free-living 

 Protozoa, certain species may occur in large numbers within a 

 small area under favorable conditions, but the majority are 

 present in comparatively small numbers. If a student who 

 has become acquainted with the representative forms intends 

 to make collections, it is well to carry a compound microscope 

 to the field in order to avoid bringing back numerous jars con- 

 taining much water but few organisms. Submerged plants, 

 decaying leaves, surface scum, ooze, etc., should be examined 

 with the microscope. When desired forms are found, they 

 should be collected together with a quantity of the water in 

 which they occur. 



When the collected material is brought into the laboratory, 

 it is often desirable to concentrate the organisms in a relatively 

 small volume of water. For this purpose the material may be 

 partly filtered rapidly through a fine milling cloth or an ordi- 

 nary filter paper and the residue quickly poured back into a 

 suitable glass container before the filtration is completed. The 

 container should be placed in a cool, well-lighted room to allow 

 the organisms to become established in the new environment. 

 Euglena and other stigma-bearing Phytomastigina will then be 

 found on the side of the container facing the strongest light, 

 just below the surface of the water, and members of the Sarco- 

 dina will be found among the debris on the bottom. Many forms 

 will not only live for several weeks under these conditions in the 

 laboratory, but also increase in number. 



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