THE WONDER OF LIFE 477 



The flowing movements of an amoeba cannot be inter- 

 preted as a result of local changes in surface tension, or the 

 like. Though surface tension phenomena are involved, 

 the movement is self-determined. Professor Jennings has 

 described the behaviour of an amoeba which pursued a 

 spherical cyst of Euglena for fifteen minutes. One amoeba 

 pursued another for a long time, finally capturing and 

 ingesting it. But after being carried for a short distance, 

 the prey partly escaped and was recaptured. It again 

 escaped, this time completely, but was pursued, overtaken, 

 recaptured, and again carried away. After five minutes 

 it escaped again, this time completely and successfully, 

 so that the hunter amoeba did not have its meal after all. 

 But this is more than surface tension. 



It seems to be one of the insignia of life that the organism 

 registers within itself the results of its experiences. As 

 Professor W. K. Clifford said : ' It is the peculiarity of 

 living things not merely that they change under the 

 influence of surrounding circumstances, but that any change 

 which takes place in them is not lost, but retained, and 

 as it were built into the organism to serve as the foundation 

 for future actions '. As Professor Henri Bergson puts it : 

 * Its past, in its entirety, is prolonged into its present, and 

 abides there, actual and acting '. 



To begin with, there must be a viable balance of up- 

 building and down-breaking the essential modus vivendi ; 

 then there must be addition to the specific structure, so 

 that some rest is possible in one part while another is 

 working hard ; along with that will go the accumulation 

 of some capital, so that the organism is not always living 

 from hand to mouth ; this makes more energetic action 

 possible, and more thorough re-creation of the specific 



