1. Look back over your study of paramecia and list the different kinds of work you saw paramecia doing; also the kinds of work you infer they can do. What organs have they to use? When there is no organ to do a given thing, _e.g._ to digest food, how is the work done? 2. What conditions are favorable to paramecia? Why are they so numerous under favorable conditions? 3. What would you call a successful animal? Are paramecia successful? Give reasons why they are or are not. Comparative Study of Protozoa To enlarge your idea of what a cell can do, spend as much more time on the one-celled animals as your course will permit. Any stagnant water may furnish several kinds. By means of reference books, identify as many as you can. In each case notice:-- 1. Its size, shape and general appearance, comparing and contrasting it with paramecium. 2. Its usual surroundings, _i.e._ the conditions it has to meet. 3. The means it has of finding out facts about its surroundings. 4. The means it has of adjusting itself to its surroundings. For example, is it stationary? If so, what does it do when conditions change? Is it locomotory? If so, how effective is its locomotion? 5. What is its food? How does it find food? 6. Can it do as many kinds of work as paramecium can? Can it do any that paramecium cannot do? If so, what? Review and Library Questions on Protozoa 1. What are the characteristics which distinguish protozoa from other animals? 2. What are the classes of protozoa? Characteristics of each class? 3. What is digestion? Where does it take place in the protozoa? 4. What results from the fact that the amœba has no cell wall? (Give at least two points.) 5. In what ways are paramecia more specialized than amœba are? How does their greater specialization show in their work? 6. What different methods of locomotion are shown among protozoa? By what means is locomotion accomplished in each case? 7. What is encysting? Name some protozoa which encyst. How long may an encysted animal live? When do they encyst? Why? 8. Give methods of reproduction among protozoa. Which method is fitted for rapid multiplication, for withstanding drouth; for renewing vitality? 9. Many scientists speak of protozoa as immortal. What argument is there to support such a statement? 10. Why are no protozoa large animals? Give at least two reasons. 11. Why are protozoa so numerous? Why more numerous in stagnant water? 12. Where are protozoa found? 13. Why are protozoa so widely distributed? 14. Write the probable history of a piece of chalk. 15. What connection is there between protozoa and some polishing powders? 16. Where in the human body are malarial protozoa found? How are they transferred from one human being to another? Why is there likely to be more malaria in newly settled regions than in older ones? If you were obliged to spend some time in a region where malaria existed, what precautions would you take?