55S ASA A. SCHAEFFER 



with the carmine-egg white and then passed on without any 

 indication of a feeding reaction, and this in spite of the fact that 

 there was present much more egg white in this particle than in 

 the previous one. 



The carmine particle that had been eaten and excreted was 

 again laid in the path of the ameba — 13. The ameba moved on 

 past in contact with the carmine without a sign of a feeding re- 

 action. Why should the same particle not be eaten the second 

 time? Had something been taken out of the particle or had 

 something been added to it? Or had the ameba been changed 

 by its first experience with the carmine in some way? 



The same grain of carmine was again laid to the right of the 

 tip of the main pseudopod — 16. There was sent out a pseudopod 

 on the right into contact with the carmine, showing that the test 

 object was sensed at a distance. The carmine grain was rolled 

 around in various directions for four minutes, when the ameba 

 moved off leaving the carmine behind. There was at no time 

 any indication of the beginning of a feeding reaction. The par- 

 tial surrounding of the carmine just before it w^as left behind — 25, 

 26 — was incidental, for the pseudopod behind the carmine was 

 being rapidly retracted. 



Four minutes later the carmine grain was laid to the left of the 

 ameba' s path — 28. The ameba moved on straight forward with- 

 out a visible change of reaction until it was one-fourth past the 

 carmine. Then a pseudopod was thrown out directly toward, 

 and into contact with, the carmine grain. The side pseudopod 

 remained in contact with the carmine until the ameba had passed 

 by. There was no attempt to roll the carmine around. The 

 main direction of movement was not even changed. Why should 

 there be such a change of reaction toward the same carmine grain? 

 When first presented it was speedily ingested. When next pre- 

 sented — 13 — it was passed by without reaction. On the third trial 

 the carmine was rolled around for several minutes. On the fourth 

 trial a pseudopod was thrown out into contact with the carmine, 

 only to be retracted later as the ameba continued in its straight 

 path forward. It is clear that the change does not lie altogether 

 within the ameba nor entirely in the carmine, and it is equally 



