12. Food and Feeding - Page 2

merrily through its tiny drop of stagnant water. If two of the legs or
arms happen to knock up casually against one another, they coalesce at
once, just like two drops of water on a window-pane, or two strings of
treacle slowly spreading along the surface of a plate. When the
jelly-speck meets any edible thing--a bit of dead plant, a wee creature
like itself, a microscopic egg--it proceeds to fold its own substance
slimily around it, making, as it were, a temporary mouth for the purpose
of swallowing it, and a temporary stomach for the purpose of quietly
digesting and assimilating it afterwards. Thus 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. Roll 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 insufferable 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 beginnings
of a mouth and stomach, for it generally takes in food and absorbs water
through a particular part of its surface, where the slimy mass 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 most primitive animals do
discriminate somehow between what is eatable and what isn't. The
amoeba has no eyes, no nose, no mouth, no tongue, no nerves of taste,
no special means of discrimination of any kind; and yet, so long as it
meets only grains of sand or bits of shell, it makes no effort in any