100 



Asa Arthur Schaefjer 



' condition of the Stentor brought about by the particles which were 

 just previously ingested. That is, the Stentor was probably in a 

 condition of partial satiety, where less and less food is taken even 

 if it should meet all the requirements of a perfect food under con- 

 ditions of hunger. The actual proofs of sucn conditions of par- 

 tial and complete satiety will be taken up later on, but it may be 

 pointed out here that in the sixth experiment the Stentor appar- 

 ently grew less and less hungry as the number of ingested particles 

 increased. 



Particles designated as in Experiment 6 



TABLE VII 



Experiment "J. Discrimination between Di^erent Species of Organisms 



The proportion of Euglena viridis and Trachelomonas volvo- 

 cina was not the same in the two experiments, so no conclusions 

 may be drawn with regard to which of these two kinds of organ- 

 isms IS eaten with the greater readiness. But it is of course clear 

 that Euglena viridis and Trachelomonas volvocina are "preferred" 

 by the Stentor to Phacus triqueter, P. longicaudus, and Tra- 

 chelomonas hispida; which is only another way of saying that 

 Stentor expresses a choice in the food which it eats. 



