44 The Animal Mind 



These three reactions make up, together with the ordinary 

 crawling locomotion, the variety of the Amoeba's experience 

 as displayed in behavior, with the addition of a peculiar set 

 of movements occurring in the absence of all mechanical 

 stimulation. When an Amoeba is floating in the water, 

 through some chance, unattached to any solid, "such a 

 condition," says Jennings, "is most unfavorable for its 

 normal activities ; it cannot move from place to place, and 

 has no opportunity to obtain food." Its mode of getting 

 out of the difficulty is to send out "long, slender pseudopodia 

 in all directions," until "the body may become reduced to 

 little more than a meeting point for these pseudopodia" 

 (378, p. 8). As soon as one of these "feelers" comes in 

 contact with a solid, it attaches itself, and the whole animal 

 following soon takes up its normal crawling locomotion. 



9. The Mind of Amceba 



Now what light does the behavior of Amceba throw upon 

 the nature of the animal's possible consciousness? The 

 first thought which strikes us in this connection is that 

 the number of different sensations occurring in an Amoeba's 

 mind, if it has one, is very much smaller than the number 

 forming the constituent elements of our own experience. We 

 human beings have the power to discriminate several 

 thousand different qualities of color, brightness, tone, 

 noise, temperature, pressure, pain, smell, taste, and other 

 sensation classes. Thus the content of our consciousness 

 is capable of a great deal of variety. It is hard to see how 

 more than three or four qualitatively different processes 

 can enter into the conscious experience of an Amceba. 

 The negative reaction is given to all forms of strong stim- 

 ulation alike, with the single exception of food. We shall 



