REACTIONS OF AMEBA TO PROTEINS 61 



in contact with the anieba, for the same ameba remained in 

 contact with the same grain of globuhn for much shorter periods 

 after the first test; but when a new grain of globuhn was intro- 

 duced the period of contact again became much longer; (4) 

 that if the first or any trial produces negative behavior leading 

 to avoidance of the globulin, the following trial is quite likely 

 to show positive behavior; (5) that three hours of almost unin- 

 terrupted contact with a large piece of globulin has practically 

 no effect on efficient feeding (496) but it is possible that the 

 feeding reaction is a little less intense, that is, instead of a food 

 cup being formed, the globulin is merely surrounded by proto- 

 plasm without including water. The formation of a number of 

 small pseudopods at the anterior end of the ameba in figures 

 498 and 499 also indicates a mildly disagreeable effect due to 

 the ingestion of the globuhn. 



Raptorial amebas 



Raptorial amebas are not attracted by globulin as strongly as 

 the granular amebas are; it is only occasionally that a grain of 

 globulin is eaten at all, and if eaten, is soon excreted. 



In the path of an ameba from a wild culture, which had been 

 tested with crystallized egg albumin, was placed a grain of globu- 

 lin (2293). The ameba moved forward toward the globulin for 

 a short distance, then stopped abruptly and broke up into sev- 

 eral pseudopods which are numbered from 1 on in the order of 

 their formation, to facilitate description. Pseudopod 1 moved 

 toward the globulin a short distance, then formed 6; but both 

 were then immediately withdrawn as 3 rapidly enlarged (2296, 

 2297). No. 7 was then projected. It curved backwards slightly 

 and attained to considerable size. It was presently arrested in 

 its development as 6 became active again and moved rapidly 

 toward the globulin grain and ingested it in a typical, though 

 probably incomplete, food cup. Pseudopods 1, 2 and 5 had 

 completely disappeared, but the vestiges of 3, 4 and 7 were 

 very conspicuous (2301). Without a period of rest or quiet 

 after the formation of the food cup, 7 suddenly became active 



