Organisms and Their Origin 109 



unjustifiable to speak of the Venus Fly-trap as 

 having a short memory. 



We used to think, as many still think, of the ac- 

 tivities of the simplest animals or Protozoa, in a 

 somewhat dull way, translating them all into mere 

 reflexes or tropisms. And no doubt there are re- 

 flexes or tropisms, and this mode of interpretation 

 must be pushed as far as it will go. But not 

 further. For the careful work of Jennings, for 

 instance, has shown us that these humble creatures 

 sometimes exhibit what may be called the first 

 hints of mind, at any rate, a pursuance of the meth- 

 od of trial and error. There is a selective be- 

 havior, such as we are ourselves continually ex- 

 hibiting. The meaning of the term selective 

 behavior may be illustrated by the story of a dog 

 which was asked to carry a walking-stick with a 

 crooked handle through a fence with close up- 

 right bars. It took the stick by the middle and 

 jammed; it tried again, but began at the wrong end 

 of the stick and jammed again. Finally, it gripped 

 the handle in its mouth and ran triumphantly 

 through. Similarly, Darwin found that the earth- 

 worms dealt in an effective way with the bifoliar 

 spurs of the Scotch fir, and even wiih strange leaves 

 of which they could have had no experience. 

 Similarly, Jennings has found that some infuso- 

 rians try one reaction after another, and select the 

 one which is fit. 



