REACTIONS OF AMEBA TO PROTEINS 67 



exposed at this time, showing that it had been incompletely in- 

 gested. The pseudopod on the left was withdrawn as the gluten 

 was incompletely reingested (1880). As the ameba moved on 

 the gluten was finally brought up to the posterior end only 

 slightly in contact with the protoplasm (1881, 1882). Proto- 

 plasmic streaming was now reversed and the gluten reingested 

 (1883) but again incompletely, for as the ameba resumed move- 

 ment in the original direction, the gluten was left beliind without 

 further reaction toward it (1884 to 1886). A grain of globuhn was 

 then placed in the ameba's path (1887). The ameba moved 

 forward into contact with it, then reversed streaming in the main 

 pseudopod, then broke up into several pseudopods and finally 

 moved off to the left (1890). The globulin grain was then 

 shifted (1891). A food cup was then formed and the globulin 

 ingested in typical manner. The ameba moved off through a 

 vestige of one of a pair of opposite pseudopods on the left indi- 

 cating nearly a balance between negative and positive behavior 

 (cf. especially with figures 2293 to 2304), without a period of rest, 

 leaving the globulin behind (1893 to 1896). A piece of gluten was 

 then laid in the path of the ameba but it was avoided. On the 

 second trial with the gluten the ameba reacted toward it with 

 indifference. 



The behavior just described may be regarded as typical for a 

 hungry raptorial ameba. These animals are stimulated at a 

 distance by such substances as globuhn, gluten, aleuronat, etc., 

 so that they move toward these objects. In many cases the 

 feeding reaction is initiated though it is seldom completed. It 

 seems that movement of the object after it is enclosed, is essen- 

 tial to complete ingestion. In all the experiments performed 

 upon this ameba only one test object was eaten: globulin (not re- 

 ported here). It is almost certain that this would have been 

 excreted soon thereafter but for the ingestion of a flagellate im- 

 mediately afterward, for no period of rest ensued after ingestion 

 and the direction of movement was changed after ingestion. I 

 have frequently observed that the eating of a flagellate or other 

 living organism has such an effect. 



