FOOD AND FEEDING 195 



what at one moment is a foot may at the next moment 

 become a mouth, and at the moment after that again a 

 rudimentary stomach. The animal has no skin and no 

 body, no outside and no inside, no distinction of parts or 

 members, no individuality, no identity. Eoll it up into 

 one with another of its kind, and it couldn't tell you itself 

 a minute afterwards which of the two it had really been a 

 minute before. The question of personal identity is here 

 considerably mixed. 



But as soon as we get to rather larger creatures of the 

 same type, the antithesis between the eater and the eaten 

 begins to assume a more definite character. The big jelly- 

 bag approaches a good many smaller jelly-bags, microscopic 

 plants, and other appropriate food-stuffs, and, surrounding 

 them rapidly with its crawling arms, envelopes them in its 

 own substance, which closes behind them and gradually 

 digests them. Everybody knows, by name at least, that 

 revolutionary and evolutionary hero, the amoeba the 

 terror of theologians, the pet of professors, and the in- 

 sufferable bore of the general reader. Well, this parlous 

 and subversive little animal consists of a comparatively 

 large mass of soft jelly, pushing forth slender lobes, like 

 threads or fingers, from its own substance, and gliding 

 about, by means of these tiny legs, over water-plants and 

 other submerged surfaces. But though it can literally turn 

 itself inside out, like a glove, it still has some faint be- 

 ginnings of a mouth and stomach, for it generally takes 

 in food and absorbs water through a particular part of its 

 surface, where the slimy mdss of its body is thinnest. 

 Thus the amoeba may be said really to eat and drink, 

 though quite devoid of any special organs for eating or 

 drinking. 



The particular point to which I wish to draw attention 

 here, however, is this : that even the very simplest and 



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