388 ELERY R. BECKER. 



pieces. They were drawn up into a pipette and transferred to 

 another watch glass. Both went into the typical stellate stimu- 

 lated condition (Figs, u and 12). At 3:20 the nucleated portion 

 (A} was still suspended in the water in the typical stimulated 

 condition. The enucleated portion (B} had lost all but two of 

 its processes, and the entire surface of the amoeba was rough and 

 wrinkled (Fig. 13). At 3:26 (A) was still stimulated, but (B) 

 had withdrawn into a wrinkled sphere (Fig. 14). At 3:30 (A) 

 was about the same, but (B} had sent out a pseudopod with a 

 rough surface. At 3:40 (A] was attached and flowing normally. 

 (B~) was still in a wrinkled condition but with a long wrinkled 

 pseudopod (Fig. 15). At 3:50 both were again drawn into a 

 pipette and shot out again in the stream of water. Both went 

 into the stimulated (stellate) condition, but in just an instant 

 (B) became again a roughened sphere. (A) remained in stimu- 

 lated condition for the next ten minutes. At 4:45 both were 

 again drawn into the pipette and shot out in a stream of water. 

 (.4) showed the typical stimulated condition, but (B) went at 

 once into a wrinkled sphere. At no time during the three days 

 of life of the enucleated portion (B) could it be made to respond 

 to the stimulus in the normal manner, as did (A), which re- 

 sponded in the same manner as the normal entire amoeba. 



Thus it is apparent that at first both portions show the typical 

 stimulated condition, but the enucleated portion loses the normal 

 response withing a short time. It can respond only by forming 

 a wrinkled sphere, as if it were unable to exert sufficient pressure 

 from within to support the pseudopods. If one watches the 

 "arms" of the stellate enucleated fragment after the initial 

 stimulation following soon after the operation of cutting the 

 amoeba into two pieces, the arms appear to melt away, the 

 surface being thrown into folds. The writer can offer no better 

 explanation than that the degree of turgidity becomes insufficient 

 to sustain the pseudopods. Thus we see that the reactions of 

 amoebae to mechanical stimuli are very much affected, the 

 verdict of Stole to the contrary. The enucleated fragment has 

 not lost its irritability, but it no longer gives the normal response. 



The nutritional processes of amoebae, especially the ingestion 

 and digestion of food have been further points of controversy. 



