398 WM. A. KEPNER AND W. CARL WHITLOCK 
that do not present the contingency of escape. The more com- 
plex type of food reaction of Ameba is concerned with the cap- 
ture of forms that set up currents in the surrounding water and 
that do present the contingency of escape. It was interesting to 
us to find that Leidy ('79) had shown in his figure 5, plate 1, two 
Urocentra captured according to our second type of food reac- 
tion, while a green plant cell was ingested apparently by the first 
type of food reaction. 
EXAMPLES OF THE FIRST TYPE OF FOOD REACTION 
a. Objects that yield oxygen to the water 
On March 15, 1919, we found that in a Petri dish there were 
many filaments of Oscillatoria that were quite quiet. None of 
these filaments were to be seen moving as Oscillatoria filaments 
frequently do. An ameba had ingested one end of one of these 
quiet filaments (fig. 1). In endeavoring to take this specimen 
from the Petri dish on to a slide, the capillary canula of the 
pipette dragged over the free end of the algal filament in such 
manner as to tear the ameba from the substratum and turn it 
through about 180 degrees. The ameba was now given time to 
fix itself again to the bottom of the dish. The free end of the 
filament was then pushed against with the canula of the pipette. 
This time instead of the ameba's being torn from the bottom of 
the dish, the part of the ameba's body that surrounded the fila- 
ment was bent from position a to position h (fig. 2.) The ameba 
was now drawn up into the capillary pipette and transferred to 
a hanging drop. The compound microscope showed that, de- 
spite this relatively rough handling, the ameba yet held on to the 
filament of Oscillatoria. Within two minutes after the cover- 
glass was placed over the glass ring, the Oscillatoria was egested. 
Soon after this the ameba again ingested one-third of the length 
of the filament and then threw it out a little later. The ameba 
a third time set to ingesting the plant. When about one-fourth 
of the filament was within the body of the ameba, a Paramecium 
collided sharply with the projecting end of the alga at right 
