42 



The Animal Mind 



back in a peculiar way by such particles. He reports 

 also (660) that the positive reaction is given to beams 

 of light which pass no nearer than 100-150 thousandths 

 of an inch to the animal. The Amoeba moves towards the 

 beam, but when it comes into contact with it, the move- 

 ment ceases, and in some cases a negative response occurs. 

 Thirdly, there is the food-taking reaction. This consists 

 for Amoeba proteus, according to Jennings, in the pushing 

 forward of a pseudopodium on either side of the particle of 



Fig. 2. 



• Food-takmg reaction of Amoeba, i, 2, 3, 4, successive stages. 

 After Jennings (378). 



food that has come into contact with the animal; the 

 bending over of the ends of the pseudopodia so as to grasp 

 the food, while "a thin sheet of protoplasm" spreads from 

 the upper surface of the animal over it ; and the final fusion 

 of the ends of the pseudopodia and the ends of this sheet, 

 so as to take the food directly into the animal's body. 

 The reaction may occur anywhere on the body surface, 

 there being no specialized mouth. It appears to be made 

 only in response to edible substances, hence there is doubt- 

 less some chemical peculiarity about the stimulus which 

 makes it effective (378). 



Kepner and Taliaferro (399) find the food-taking reaction 



