BIOLOGY AND HUMAN SOCIETY.
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The pig, however, is not the only captive animal treated by
Man while alive as if it were one of his allies, but exploited at
its death as if it were game or vermin. The rabbit, though
usually treated as vermin, may when in captivity undergo
modification like the pig. The canary, among captive birds, has
been modified as much as the rabbit or the pig among captive
animals. Among captive plants we note that while species of
interest to Arboriculture on aesthetic grounds are left as un-
modified as those grown for Economic reasons, the species trans-
ferred as captives from their native wilds as being of interest to
Horticulture on aesthetic grounds, become the objects of a
biological attention that always equals, and sometimes seems
to exceed, that bestowed on our strictly economic garden legumes
and potherbs. This fact is of some intrinsic interest, and
strengthens the suggestion, made on other grounds, that the
treatment by Human Society of its three classes of useful plants
differs in degree only, not in character.
The evidence afforded by more than one crop, notably by
the rubber-yielding Hevea, that the transition from wild
Exploitation to controlled Exploitation may be automatic, is
clear. This particular crop affords equally clear evidence of
the transition from controlled Exploitation or Enslavement, to
Domestication or Symbiotic Partnership with Man. The
introduction of Hevea to cultivation in Ceylon and Malaya dates
from 1876. Twenty years later its controlled exploitation in
Asiatic plantations, as contrasted with its wild exploitation in
Amazonian forests, became a trade activity. Twenty years
more saw the wild exploitation of Brazilian Hevea reduced to
relative unimportance. Now, the cultivation of Hevea in south-
eastern Asia is an industry of such consequence that it absorbs
the individual attention of three Biological Institutes whose
energies are devoted to the scientific and technical tasks of
improving the cultivation and increasing the yield of this single
crop; of protecting it against the attacks of pests and blights
and the development of physiological defects; of perfecting the
preparation and finding uses for the product it yields. Already
Rubber is one of those crops with which Man has established a
symbiosis so intimate that it forms an integral part of Human
Society.
The useful animals in symbiotic partnership with Man