PROTOZOANS. 



THE AMCEBA. 



The Amoeba is selected as the first animal for study, 

 because of its extreme simplicity. In it we are dealing 

 with animal life at its lowest terms. 



It is very small, usually less than a hundredth of an 

 inch in diameter, and can be studied only with the aid of 

 a microscope. Examine one that has been taken up in a 

 drop of water, mounted on a glass slip, covered, and placed 

 in the field of a microscope. 1 



First find it. This will be task enough for a moment 

 for a beginner, even if the amoeba be in the field; for it 

 presents so little likeness to familiar animals, that it might 

 as readily be taken to be anything else. It appears like a 

 little drop of jelly spreading out on a flat surface, trans- 

 lucent in its central portion, and very transparent around 

 its border. Reference to the accompanying figure will aid 

 in recognizing it. That it is alive will not be ascertained 

 at the first glance, but may be learned from watching its 

 slowly changing outline for a moment or two. After find- 

 ing it, and after learning by a few trials how, by moving 1 

 the glass slide, to bring it back into the center of the field 

 when it moves out, and how to keep it in focus by turning 

 the adjustment screws on the microscope, then study its 

 general structure and its movements. 



1 If the student be working alone, he will follow the directions given 

 to the teacher (see Appendix, p. 278) for collecting amcebas, and pre- 

 paring them for examination. 



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