Animal life and intelligence . flickers out and is this true of all animals ? Can we say that death—as distinct from being killed—is the natural heritage ofevery creature that lives ? 12 Animal Life and Intelligence. One of the simplest living creatures is the amceba. Itconsists of a speck of nucleated protoplasm, no larger thana small pins head. Simple as it is, all the essential life-processes are duly performed. It is a centre of waste andrepair; it is sensitive and responsive to a stimulus; respi-ration and nutrition are effected in a simple and primitivefashion. It is, moreover,
Animal life and intelligence . flickers out and is this true of all animals ? Can we say that death—as distinct from being killed—is the natural heritage ofevery creature that lives ? 12 Animal Life and Intelligence. One of the simplest living creatures is the amceba. Itconsists of a speck of nucleated protoplasm, no larger thana small pins head. Simple as it is, all the essential life-processes are duly performed. It is a centre of waste andrepair; it is sensitive and responsive to a stimulus; respi-ration and nutrition are effected in a simple and primitivefashion. It is, moreover, reproductive. First the nucleusand then the protoplasm of the cell divide, and in place ofone amoeba there are two. And these two are, so far aswe can tell, exactly alike. There is no saying which ismother and which is daughter; and, so far as we can seeat present, there is no reason why either should die. It isconceivable that amoebae never die, though they may bekilled in immense numbers. Hence it has been plausibly Fig. 4.—Amoeba. 1. An amoeba, showing the inner and outer substance (endosarc and ectosare); a pseudo-podium, ; the nucleus, n.; and the contractile vesicle, 2. An amceba dividing intotwo. 3. The division just effected. maintained that the primitive living cell is by naturedeathless; that death is not the heritage of all livingthings; that death is indeed an acquisition, painful indeedto the individual, but, since it leaves the stage free for theyounger and more vigorous individuals, conducive to thegeneral good. In face of this opinion, therefore, we cannot say thatall animals grow old and die; but we may still say thatall animals, with the possible exception of some of thelowest and simplest, exhibit, after a longer or a shortertime, a waning of the vital energies which sooner or laterends in death. 10. Animals reproduce their kind. We have just seen The Nature of Animal Life. i 3 the nature of reproduction in the simple unicellular
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