BIOLOGY AND HUMAN SOCIETY. 77
by the fowling-piece which, at any rate in Europe, now enables
Man to treat his old friends as vermin. That faithful "friend of
"man," the horse, is learning to treat his trust in Man much
as Man is taught to treat his own trust in Princes. Thanks to
the influence of the internal combustion engine, Man has trans-
ferred seven-eighths of his old friends from city streets and country
roads to the knacker's yard, and proposes to exclude them
altogether from the fields of peace and of war. Nor is the
position of that pillar of civilisation, the cow, so secure
as it once seemed to be. Makers of margarine now supply urban
consumers with artificial products of vegetable origin that
differ from butter only in the matter of their vitamins. Now
that biochemistry can isolate and synthesise certain of these
vitamins Human Society may hope that animals and plants
now regarded as negligible or noxious can be exploited to yield
the vitamins required for addition to Human Society's artificial
supplies of auxiliary food-stuffs.
Human Society includes more than one "symbiosis of Man
"with certain animals and plants," regarding which Biology
finds it necessary to retain an open mind as to whether they
should be considered symbioses established by Man with the
organisms concerned, or symbioses established by the organisms
concerned with Man. One of these doubtful cases is that of
the cat, which, Human Society and Biology alike admit, does
on occasions condescend to treat Man as a friend. But whereas
Human Society is sometimes disposed to imagine that the cat
has been induced by Man to share the comforts which Human
Society can afford it, Biology is often compelled to think that the
cat only appreciates the comforts which Human Society affords
sufficiently to enable it to endure the companionship of Man.
Another doubtful case is that of the pigeon, whose homing habit
induces Human Society to think that Man must have estab-
lished symbiosis with the bird, but leads Biology to consider
it possible that the pigeon, like the cat, may think more of the
place in which it finds food and shelter than of the person who
provides these comforts. Those of us who have seen the interior
of the great hall at Hever, can recognise that mediaeval and
Renaissance columbaria were human contrivances designed to
facilitate the exploitation of the bird, on the principle that led
Man to construct bee-hives in order to facilitate his plunder of