s when they get the chance. Thus, both
monkeys and primitive men will eat grubs and small soft animals, and
also the eggs of birds. Whilst the cat tribe, in regard to the
chemical action of their digestive juices, are so specialised for
eating raw meat that it is practically impossible for them to take
vegetable matter as even a small portion of their diet, and whilst, on
the other hand, the grass-eating cattle, sheep, goats, antelopes, deer
and giraffes are similarly disqualified from any form of meat-diet,
most other land-mammals can be induced, without harm to themselves, to
take a mixed diet, even in those cases where they do not naturally
seek it. Pigs, on the one hand, and bears, on the other, tend
naturally to a mixed diet. Many birds, under conditions adverse to the
finding of their usual food, will change from vegetable to animal
diet, or _vice-versa_. Sea-gulls normally are fish-eaters, but some
will eat biscuit and grain when fish cannot be had. Pigeons have been
fed successfully on a meat diet; so, too, some parrots, and also the
familiar barn-door fowl. Many of our smaller birds eat both insects
and grain, according to opportunity. Hence it appears impossible to
base any argument against the use of cooked meat as part of man's diet
upon the structure of his teeth, or upon any far-reaching law of
Nature which decrees that every animal is absolutely either fitted
(internally and chemically, as well as in the matter of teeth) for a
diet consisting exclusively of vegetable substances, or else is
immutably assigned to one consisting exclusively of animal substances.
There is no _a priori_ assumption possible against the use as food by
man of nutritious matter derived from animals' bodies properly
prepared.

So far as _a priori_ argument has any value in such a matter, it
suggests that the most perfect food for any animal--that which
supplies exactly the constituents needed by the animal in exactly
right quantity and smallest bulk--is the flesh and blood of another
animal of its own species. This is a startling theoretical
justification--from the purely dietetic point of view--of
cannibalism. It is, however, of no conclusive value; the only method
which can give us conclusions of any real value in this and similarly
complex matters is prolonged, full, well-devised, well-recorded
experiment. At the same time, we may just note that the favourite food
of the scorpion is the juice of the body of another scorpion, an