562 ASA A. SCHAEFFER 



amount of egg white were readily ingested the first time each one 

 was presented, for the first few trials. But on later trials the 

 ingesting process, though initiated in typical fashion, was not 

 completed. The ameba seemed to discover its mistake too late 

 to completely avoid the carmine, even after a few trials had been 

 made. On the last few trials, however, no indications of a food 

 cup were seen when fresh pieces of carmine of the same grade were 

 laid near the ameba. In contrast to the behavior of the ameba 

 toward carmine grains adulterated with a slight amount of egg 

 white, is that toward carmine grains containing a considerable 

 amount of egg white ; for no food cup was started over carmine 

 grains of the latter kind. This is a point worth noting, for the 

 food value of the latter grains is much greater than that of the 

 former; and the solubility is also greater. There is sufficient 

 evidence already at hand to make it clear that it is not merely the 

 presence of a small quantity of food that induces the feeding re- 

 action, but that there are other factors concerned. This conclu- 

 sion is strengthened by the fact that neither gelatin nor aelosoma 

 meat were eaten, gelatin being presumably a food substance and 

 aeolosoma being actually digestible as later experiments will 

 show. That the behavior may be regarded as that of a normal 

 ameba seems quite proper because of the ingestion of various 

 food organisms during the course of the experiment. 



One of the puzzling features of the behavior toward carmine, 

 is that a carmine grain that has once been eaten will not be eaten 

 again. This looks as if the carmine grain had undergone a 

 change in passing through the ameba's body. But further dis- 

 cussion of this point will be postponed until the experiments of 

 the next ameba have been described. 



All the carmine grains that were eaten were ejected a few min- 

 utes thereafter. In the first case the carmine was ejected so soon 

 after eating that one is inclined to think that the carmine acted 

 as a disagreeable stimulus, and was not regarded merely as an 

 indifferent body, such as the indigestible remains of a food mass. 

 This is rendered the more probable by reason of the fact that the 

 ameba, immediately after ingestion, reversed its direction of 

 locomotion and moved away so that the carmine should lie at 



