On Longevity And Shortness Of Life
about them. In animals fat is sweet, and hence bees are longer-lived
than other animals of larger size.
It is amongst the plants that we find the longest life-more than
among the animals, for, in the first place, they are less watery and
hence less easily frozen. Further they have an oiliness and a
viscosity which makes them retain their moisture in a form not
easily dried up, even though they are dry and earthy.
But we must discover the reason why trees are of an enduring
constitution, for it is peculiar to them and is not found in any
animals except the insects.
Plants continually renew themselves and hence last for a long
time. New shoots continually come and the others grow old, and with
the roots the same thing happens. But both processes do not occur
together. Rather it happens that at one time the trunk and the
branches alone die and new ones grow up beside them, and it is only
when this has taken place that the fresh roots spring from the
surviving part. Thus it continues, one part dying and the other
growing, and hence also it lives a long time.
There is a similarity, as has been already said, between plants
and insects, for they live, though divided, and two or more may be
derived from a single one. Insects, however, though managing to
live, are not able to do so long, for they do not possess organs;
nor can the principle resident in each of the separated parts create
organs. In the case of a plant, however, it can do so; every part of a
plant contains potentially both root and stem. Hence it is from this
source that issues that continued growth when one part is renewed
and the other grows old; it is practically a case of longevity. The
taking of slips furnishes a similar instance, for we might say that,
in a way, when we take a slip the same thing happens; the shoot cut