These considerations then introduce much difficulty into our conception of the idea of an Individual.
ANIMAL IMMORTALITY
But, further than this, we are confronted by by another problem. If we regard a mass of coral as an individual because it arises by continuous growth from a single egg, then it follows that some corals must be thousands of years old.
Some of the lower animals may be cut into pieces, and each piece will develop into an entire organism. In fact the realisation of the idea of an individual gradually becomes more and more difficult, and the continuity of existence, even among the highest animals, gradually forces itself upon us. I believe that as we become more rational, as we realise more fully the conditions of existence, this consideration is likely to have important moral results.
It is generally considered that death is the common lot of all living beings. But is this necessarily so? Infusoria and other unicellular animals multiply by division. That is to say, if we watch one for a certain time, we shall observe, as already mentioned, that a constriction takes place, which grows gradually deeper and deeper, until at last the two halves become quite detached, and each swims away independently. The process is repeated over and over again, and in this manner the species is propagated. Here obviously there is no birth and no death. Such creatures may be killed, but they have no natural term of life. They are, in fact, theoretically immortal. Those which lived millions of years ago may have gone on dividing and subdividing, and in this sense multitudes of the lower animals are millions of years old.
FOOTNOTES:
[15] Address to Microscopical Society, 1890.
[16] Ants, Bees, and Wasps, and The Senses of Animals.
[17] Prof. Drummond (Tropical Africa) dwells with great force on the manner in which the soil of Central Africa is worked up by the White Ants.
[18] Lankester, Comparative Longevity. See also Weismann, Duration of Life.