I20 Asa Arthur Schaeffer 



lowing. Does not Stentor react or behave differently to such 

 indigestible particles as carmine or india ink after being in contact 

 with them for a few minutes or half an hour? In other words, may 

 not the Stentor under these conditions be "educated" into reject- 

 ing carmine after having for some time ingested this substance? 



The paper by Metalnikow, referred to in the introduction, bears 

 upon this very point. This author worked upon paramecium 

 and found that if these organisms are fed with carmine for 15 

 days or so, they cease to take up this substance. "Fiittert man 

 Paramecien sehr lange Zeit hindurch nur mit einem Farbstoff", z. B. 

 mit Karmin, so kann man haufig nachstehende interessante Er- 

 scheinung beobachten. Anfangs, wahrend der ersten Tage des 

 Fiitterns, bilden sich in einem jeden Infusor 30-40 kleine, gaf arbte, 

 Karmin enthaltende Vacuolen. Hierauf nimmt die Zahl der 

 Vacuolen immer mehr und mehr ab. Bereits nach wenigen Tagen 

 enthalt ein jedes Infusor nicht mehr wie 15-20 Vacuolen, wahrend 

 nach 10-15 Tagen nicht wenige Infusorien angetrolfen werden, 

 welche keine einzige gef arbte Vacuole mehr en thai ten. Nach 

 einem noch grosseren Zeitraum horen sammtliche Infusorien auf 

 Karmin zu verschlucken" (/. %., p. 183, 184). 



I attempted to verify Metalnikow's results upon Stentor and 

 expected at the outset to find perhaps a greater capacity in Stentor 

 to acquire such a "ganz neue Fahigkeit" than in Paramecium, 

 because of the generally accepted notion that Stentor is more 

 highly developed as far at least as its "action system" is concerned. 

 It would be in line with the results obtained by my other experi- 

 ments on Stentor. But I was disappointed, as the following experi- 

 ments show. 



In 5 large covered dishes were placed 60 watch glasses, each 

 one being filled with about 5 cc. of fresh, weak, filtered hay infusion. 

 In 6 of these glasses were placed S ten tors; in 6 more were placed 

 Stentors and paramecia; ratio, i :io; 6 others contained Stentors 

 and Euglenae, i :ioo; 6 others contained Stentors, paramecia, and 

 india ink; 6 others, Stentors, paramecia, and carmine; 3 others 

 Stentors and india ink; 3 others, Stentors and carmine; 6 others, 

 paramecia; 3 others, paramecia and india ink; 3 others, paramecia 

 and carmine; 6 others, paramecia and Euglena; 3 others, para- 



