ichthyophagists (fish eaters), and more specifically
of elephant eaters, crocodile eaters, ostrich
eaters, locust eaters, &c. The fish eaters heaped
fish upon heated stones, removed the backbones,
mashed the flesh into a sort of cake, and dried
it in the sun. Except the pig, which the Arabs
regarded with horror on account of its dirty and
hideous person, almost all animals were welcome
to them.

We need not follow Dr. Reich in his extensive
researches into the food of all nations. The
foregoing varieties suffice to indicate that the
human stomach can be contented with very
simple food, and very rude cookery, and will
also master almost every variety of organic
substance, and please itself with every combination
which ingenuity can devise. There are tribes
which subsist entirely on animal food, and there
are tribes which subsist entirely on vegetable
food, and there are those, by far the greater
number, which subsist on varieties of both.
Much depends on climate and mode of life; not
a little on custom and prejudice. If the labourer
in Benguela is satisfied with a handful of manioc
meal, and is kept in "condition" by this modest
diet, the labourer in England would show but
shrunken muscles and feeble energy on such
food; nor could either of them flourish on the
quantities of raw flesh and train oil eagerly
devoured by the Esquimaux. Rice and pulse
keep the sepoy in vigour, but the English
soldier, under the same conditions of climate,
would languish on such food. It is a popular
error to suppose that in hot climates meat and
fat are instinctively avoided, and are proper
only for cold climates. There are numerous
tribes in the hottest parts of Africa which
always eat meat when they can get it, and eat
it gluttonously; and the great carnivorous
animals are mainly inhabitants of hot climates.
The truth is, there is a certain adaptation
between the organism and its food which is
quite independent of temperature; and just as
there are flesh-feeders and vegetable-feeders
among animals (the food of both coming to the
same thing after being digested), so there are
races of men organised to flourish on different
kinds of food. It is in vain to say all men are
alike, and therefore must be equally adapted to
digest the same kind of food. Alike they are, but
also different. Even among the same tribe, or race,
we find important individual differences. One
man cannot digest eggs, another cannot digest
milk, a third cannot eat mutton, a fourth cannot
touch butter, a fifth is made ill by tobacco, a
sixth by strawberries, and so on. Now, it is
purely a question of adaptability whether food
shall be nutritious or the reverse. We know
that cabbage will feed cows, monkeys, and men,
because cabbage can by them be digested; but
it will not feed fish, cats, or vultures, simply
because it cannot be digested by them. And
the cabbage which the monkey eats uncooked
must be cooked for the man, because his
digestive powers are feebler.

All cooking is a preparatory digestion. The
ancients used to consider digestion itself only a
process of cooking, and in some respects they were
right. In proportion as the food has been well
cooked there is less labour thrown upon the
stomach, which will have to grind and mash the
food, to reduce it to a pulp and a liquid. For it
is a fact worth bearing in mind, that only liquid
food is capable of nourishing an organism. In
however solid a condition the substance enters the
stomach it must be reduced to liquid before any
of it can nourish; all that is not capable of
being made liquid, or of being held in solution,
passes away as worthless. The caterpillar, for
example, devours daily about twice its own
weight of solid food, yet exact experiment has
proved that a caterpillar which in twelve hours
voided from fifteen to eighteen grains of refuse,
only gained one or two grains in weight during
that period, the fact being that it had only
pressed out the juices of the leaves, and voided
all the solid parts. Had its digestive powers
been more vigorous, it would have eaten less
and liquefied more. The same thing is true of
the higher organisms. In proportion to their
power of liquefying food is the quantity of
nutriment they extract from articles of food.

And the reasons why food must be liquid
before it can nourish an organism are twofold:
first, the food has to be conveyed from the
stomach to the various parts of the body which
have to be nourished; and as it is conveyed in
canals which are everywhere closed—blood-vessels
with no openings in their walls to let the food
escape—it would be for ever carried to and fro
by the torrent of the circulation (most accurate
phrase!); and the parts of the body through
which this torrent rushes would be as little
benefited by the food as if none were there.
Secondly, supposing openings to exist, or to
be ruptured, and the solid food to be
deposited on the organs, no nutrition could take
place; because these organs are made up of
innumerable little cells or vesicles, every one of
which must separately be fed, and no one of
which has any mouth or opening for the food
to enter.

Thus, the food has first to be carried away by
a vast network of closed vessels, through the
walls of which it must ooze; and then it has to
ooze through the walls of the tiny cells
constituting the individual atoms of each organ. It
is obvious that only liquid food can thus pass
out of the blood-vessels and into the cells. It
does so in virtue of a remarkable law—named
the law of Endosmosis—by which a fluid
moistening one side of a membrane will gradually
change places with a different fluid moistening
the other side of this membrane. Outside the
blood-vessel there is a fluid, and with this the
blood sets up a process of exchange. The blood
thus oozed Irom the vessel now finds itself
outside the membrane (cell wall) of the cells which
contain liquid; and between these two a similar
process of exchange takes place: the cell gets
new food, and gets rid of wasted material.

We here reach the final stage of the long
history of cooking and digesting. All those
manifold efforts and stratagems by which food is