78
THE ESSEX NATURALIST.
the bee. But when we watch the habits of the pigeons in places
like Trafalgar Square or Victoria Station, we realise that, in
spite of the resolution of certain Metropolitan municipal
authorities that pigeons must be extirpated as vermin, the bird
refuses to leave London, and feel that the symbiosis with Man
may, in this case, have been initiated by the bird.
Among plants whose symbiosis with Man is evident, but
where the responsibility for its origin is doubtful, must be
placed the weeds that find in Man's fields and gardens their
favourite, and in some cases, their only homes. Here the
evidence that Man did not intentionally originate the symbiosis
seems clear. But it is equally clear that Man made the sym-
biosis possible by unwittingly providing ecological conditions of
which certain plants, that find these conditions favourable, have
been prompt to take advantage. This, therefore, is a type of
symbiosis that differs from other types in having been fostered and
accepted, equally unconsciously and automatically, by both
partners.
Among the plants that, in symbiosis with Man, constitute
Human Society, it is disturbing to find some that lead a double
life as reprehensible as that of Man himself, at his worst. One
cultivated crop in particular almost recalls "the strange case of
"Dr. Jekyll and Mr. Hyde." Hemp, as the source of a valuable-
fibre, is a plant with which Man has lived in respectable symbiosis
since prehistoric times: hemp, as the source of a potent nar-
cotic, has lived in disreputable symbiosis with Man since the
dawn of history. Yet in this notorious case, which is not singular
when we recall the dealings of Human Society, in its developed
stage, with drugs of vegetable origin like cocaine and morphia,
though Prejudice attributes all the blame to the plant, Justice
induces Biology to point out that some of the opprobrium rests
on Man. It is the abuse, not the use, of hemp as a drug, which
makes this particular symbiosis disgraceful, and Biology re-
members, even if Human Society sometimes forgets, that what
is true of hemp may, at times, be true of betle, cacao, coffee,
tea or tobacco. Biology observes that whereas Man's dealings
with plants that provide him with food and dress and shelter,
normally begin with Exploitation, which often becomes modified
into Enslavement and sometimes develops into Symbiosis, his
dealings with plants that yield substances he can chew, or drink,