PARAMECIUM OF CLASS INFUSORIA 



101 



direction and try again. This may be repeated, and is known as 

 the "avoiding reaction/' Such a reaction really involves simply 

 one or more negative responses. These animals are constantly sam- 

 pling the water and avoiding the conditions which are least favor- 

 able. This may be repeated in all directions. The same type of 

 persistence is practiced in attempting to surmount a solid barrier. 



i 



Fig. 43. — Diagram of the course and movement of Paramecium through the 

 water. Notice the spiral path. (From Jennings, Behavior of the Lower Organisins, 

 published by The Columbia University Press.) 



