92 



Asa Arthur Schaefjer 



To determine what would be the effect of feeding in a mixed 

 stream three kinds of particles, two that were not food and one 

 that was food, natural starch grains, powdered glass, and Phacus 

 triqueter were sucked up into different capillary pipettes and fed 

 to a normal Stentor with the following results. 



Experiment J. Discrimination bettueen Starch Glass, and Phacus 



p = Phacus; s = starch grains; g = particles of glass. The particles of starch and glass were selected 

 of a size about equal to that of Phacus. 



TABLE III 



Experiment 5. Discrimination between Starch, Glass and Phacus 



SUMMARY 



Eaten, 21 Phacus and i starch grain. 



Rejected, 12 starch grains, 11 particles of glass, and 7 Phacus. 



At this point the Stentor contracted and swam away. The dis- 

 crimmation in this experiment is of about the same degree of 

 accuracy as in the two preceding experiments. The specimens of 

 Phacus which were rejected may not represent a mistake in dis- 

 crimination at all, but may be due toa condition of partial satiety, 



