64 MIND IN EVOLUTION CHAP. 



cavity was formed in the anterior part of Amoeba c, reaching back 

 nearly or quite to its middle, and much more than sufficient to 

 contain the ball b. Amoeba a now turned into a new path ; 

 Amoeba c followed. After the pursuit had lasted for some time 

 the ball b had become completely enveloped by Amoeba c. The 

 cord connecting the ball with Amoeba a broke, and the latter 

 went on its way, disappearing from our account. Now the 

 anterior opening of the cavity in Amoeba c became partly closed, 

 leaving only a slender canal. The ball b was thus completely 

 enclosed, together with a quantity of water. There was no 

 adhesion between the protoplasm of b and c ; on the contrary, as 

 the sequel will show clearly, both remained independent, c merely 

 enclosing b. 



" Now the large Amoeba c stopped, then began to move in 

 another direction, carrying with it its meal. But the meal the 

 ball b now began to show signs of life, sent out pseudopodia, 

 and became very active ; we shall therefore speak of it henceforth 

 as Amoeba b. It began to creep out through the still open canal, 

 sending forth its pseudopodia to the outside. Thereupon Amoeba 

 c sent forth its pseudopodia in the same direction, and after 

 creeping in that direction several times its own length, again 

 enclosed b. The latter again partly escaped, and was again 

 engulfed completely. Amoeba c now started again in the opposite 

 direction, whereupon Amoeba b, by a few rapid movements, 

 escaped from the posterior end of Amoeba c and was free being 

 completely separated from c. Thereupon c reversed its course, 

 overtook b, engulfed it completely again, and started away. 

 Amoeba b now contracted into a ball and remained quiet for a 

 time. Apparently the drama was over. Amoeba c went on its 

 way for about five minutes without any sign of life in b. In the 

 movements of c the ball became gradually transferred to its 

 posterior end until there was only a thin layer of protoplasm 

 between b and the outer water. Now b began to move again, 

 sent pseudopodia through the thin wall to the outside, and then 

 passed bodily out into the water. This time Amoeba c did not 

 return and recapture b. The two Amoebae moved in opposite 

 directions and became completely separated. The whole per- 

 formance occupied about fifteen minutes." (Pp. 17, 18.) 



This behaviour, as Mr. Jennings justly remarks, is 

 evidently complex, and " analysis into simple reactions 

 and simple stimuli is difficult if possible at all." Un- 

 doubtedly the impression made both by this and other 

 observations is that the amoeba's action is of sensori- 

 motor type. It certainly uses only two or three type 



