ON THE FEEDING HABITS OF AMEBA 567 



by ingesting previously another carmine grain three times, and 

 coming into contact with it five times thereafter. The ameba's 

 appetite seems, however, to have improved from contact with the 

 carmine, and finally ingestion took place as a consequence. 



So much for the behavior of granular amebas toward carmine ; 

 let us now take up a few experiments in which raptorial amebas 

 were tested with this substance. 



A small clear raptorial ameba which had partly eaten a grain 

 of aleuronat and then rejected it, reacted faintly positively to a 

 grain of carmine of grade 2 which had been placed near it — 1782. 

 The grain of carmine was then placed in contact with the ameba — 

 1786. A decided positive reaction followed but no attempt at 

 ingestion was observed. Subsequent tests with pure carmine 

 brought about reactions essentially similar to these. 



Another raptorial ameba that had eaten a piece of grain gluten 

 and later avoided a solution of carmine in a capillary tube, 

 avoided a grain of pure carmine at first, but later reacted posi- 

 tively — 2188. No attempt at ingestion was observed. 



In the path of another raptorial ameba which had reacted 

 only mildly positively toward a solution of egg albumen, and 

 toward globulin and aleuronat, but which had ingested a flagel- 

 late, was placed a grain of carmine of grade 2-2250. The ameba 

 at first seemed to avoid the carmine but presently a pseudopod 

 was sent out toward it, and a few seconds later a food cup was 

 formed and the carmine ingested with a considerable amount of 

 'water. The direction in which the ameba moved off almost im- 

 mediately after ingestion was such that the carmine lay at once 

 in the posterior part of the ameba. 



A grain of aleuronat was then placed in the ameba's path. 

 There was only a mild positive reaction. The aleuronat was fol- 

 lowed by the carmine grain — 2260. First there was observed an 

 avoiding reaction but presently a side pseudopod was thrown out 

 anterior to the carmine, which remained in contact with it while 

 the ameba moved on. 



An interesting variation of the reaction to carmine, when once 

 inside the body, was disclosed by an experiment upon the ameba 

 shown in figure 1513. This was a raptorial ameba and was 



