EXERCISE 132 (Continued) 



Sound stimulation. Try low sounds of various kinds ; scratch or rub the table with the jar ; agitate 

 the water gently. 



1 . How can you tell that your animal is sensitive to sound ? 



2. Is it sensitive to vibrations in solids or liquids, other than sounds ? 



Questions. 1. What advantage do you think the animal gets from reacting as it does to various 

 disturbances ? 



2. In a given situation, does the animal seem to choose what to do ? 



3. Are there any movements that could be considered offensive rather than, or as well as, defensive ? 



Movements of plants. If a sensitive plant is available, study the location, the kind, and the intensity 

 of disturbance necessary to set up the characteristic reaction. 

 Describe the plant's movements. 

 Note how much time it takes to recover the open position. 



Questions. 1. Does illumination affect the sensitiveness? 



2. What benefit does the plant seem to derive from the reaction to this disturbance ? 



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