cycles. All living things are born into the world, grow up, and
die, and it was to the cycle of life, from the egg to the adult which
produces eggs, that he gave the name individual. In a simple animal
like Hydra there is no difficulty in accepting this plain definition
of individuality; but Huxley went on to compare with Hydra a compound
creature like the Portuguese man-of-war, which really is composed of a
colony of Hydra-like creatures, the different members of the colony
being more or less altered to serve different functions. All these
have come from the branching of a single simple creature produced from
an egg, and to the whole colony Huxley gave the name of zooelogical
individual. The salps give a still wider interpretation to this view
of individuality. The original salp produced from the egg gives rise
to many salps, which may either remain attached in a chain, or,
breaking away from one another, may live separately. Huxley extended
the use of the word _individual_ so as to include as a single
zooelogical individual the whole set of creatures cohering in chains or
breaking apart, which had been produced by budding from the product of
a single egg-cell. This subtle analysis of ideas delighted and
interested his contemporaries, and the train of logical examination of
what is meant by individuality has persisted to the present time. Like
all other zooelogical ideas, this has been considerably altered by the
conception of evolution. Zooelogists no longer attempt to stretch
logical conceptions until they fit enormous and different parts of the
living world. They recognise that the living world, because it is
alive, is constantly changing, and that living things pass through
different stages or kinds of individuality in the course of their
lives. A single egg-cell is one kind, perhaps the simplest kind, of
zooelogical individual; when it has grown up into a simple polyp it has
passed into a second grade of individuality; when, by budding, the
polyp has become branched, a third grade is reached, and when the
branches have become different, in obedience to the different purposes
which they are to serve in the whole compound creature, a still
further grade is reached. Huxley's attempt to find a meaning for
individuality that would apply equally to a single simple creature, to
a compound creature, and to the large number of separate creatures,
all developed by budding from one creature, is a striking instance of
his sin