are in the torrid zone several grains and plants,
which supply the inhabitants with food, either
used along with rice and maize, or entirely
occupying their place. Such are, in the New
Continent, yams (Dioscorea alata), the manihot
(Iatropha manihot), and the batatas (Convolvulus
batatas), the root of which, and the fruit
of the pisang (Banana musa), furnish universal articles
of food. In the same zone in Africa, doura
(Sorghum), pisang, manihot, and yams, occur.
In the East Indies and in the Indian Islands, several
palms and cycadeæ, which produce the
sago; pisang, yams, batatas, and the bread-fruit
(Artocarpus incisa), are eaten. In the islands
of the South Sea, grain of every kind disappears;
its place being supplied by the bread-fruit-tree
and the pisang. In the tropical parts of New
Holland there is no agriculture. Nature does
all the work; the inhabitants living on the produce
of the sago, of various palms, and some
species of arum.

In the high lands of South America, the distribution
is similar to that of the other degrees
of latitude. Maize, indeed, grows to the
height of seven thousand two hundred feet
above the level of the sea, but only predominates
between three thousand and six thousand
feet of elevation. Below three thousand feet it
is associated with the pisang and other vegetables;
while, from six thousand to nine thousand
two hundred and sixty feet the European grains
abound— wheat in the lower regions, and rye and
barley in the higher; along with which, Chenopodium
Quinoa, as a nutritious plant, must also
be enumerated. Potatoes alone are cultivated
at a height of from nine thousand two hundred
and sixty feet to twelve thousand three hundred
feet.

To the south of the Tropic of Capricorn,
wherever agriculture is practised, considerable
resemblance with the northern temperate zone
may be observed. In the southern parts of
Brazil, in Buenos Ayres, in Chili, at the Cape
of Good Hope, and in the temperate zone of
New Holland, wheat predominates; barley and
rye make their appearance, however, in the
most southern parts of these countries, and in
Van Diemen's Land. In New Zealand the
culture of wheat is said to have been tried
with success; but the inhabitants make the
Acrostichum furcatum their main article of sustenance.

Thus, it appears, in regard to the predominating
kinds of grain, that the earth may be
divided into five grand divisions, or kingdoms:
the Kingdom of Rice, of Maize, of Wheat, of
Rye, and lastly of Barley and Oats. The first
three are the most extensive; maize has the
greatest range of temperature; but rice may be
said to support the greatest number of the human
race.

Corn was the chief export from Britain under
the Romans, and in the fourth century the
armies of Gaul and Germany depended for their
subsistence upon these annual supplies. In the
year 359, some of the Roman colonies situated
in the Upper Rhine, having been plundered by
their enemies, the Emperor Julian built a fleet
of eight hundred barks, which he despatched
to Britain for corn. The historian Zosimus
states that, on its return, the inhabitants of the
plundered towns and villages received enough
not only to last them during the winter, but,
after they had sown their lands in the spring, to
leave them sufficient for their subsistence until the
next harvest. Malmesbury says that, in the reign
of Stephen, "London was a granary where corn
could always be bought cheaper than anywhere
else." King Richard, after his return from the
East, issued a prohibition against the exportation
of corn, "that England might not suffer from
the want of its own abundance." The violation
of this law is stated to have been punished with
merciless severity; some vessels having been
seized in the port of St. Valery, laden with English
corn for the King of France, Richard burned
both the vessels and the town, hanged the
seamen, and also put to death some monks
who had been concerned in the illegal transaction.
After all this wild devastation, the king
divided the corn among the poor. In 1382, a
general proclamation was issued, prohibiting,
under penalty of the confiscation of the vessel
and cargo, the exportation of corn or malt to
any foreign country, except to the king's territories
in Gascony, Bayonne, Calais, Brest, Cherbourg,
Berwick-upon-Tweed, and other strong
places belonging to the king. Twelve years
afterwards, all English subjects were allowed to
export corn to any country not hostile, on
paying the dues.

The grain of wheat, like that of all other
grasses, is popularly called a " seed," but botanically
it is a fruit; because, in its ripe condition,
it is enclosed in the adhering shell (pericarp)
corresponding to the loose pod of such
fruits as the pea or bean. This husk is
formed of a much firmer substance than the
body of the grain, and, in the process of grinding
becoming separated, takes with it the outer
layers of the grain itself. These outer layers
differ from the central mass; while the body
of the seed is composed of cells densely filled
with the white starch granules which give the
characteristic appearance to fine flour, the outer
layers contain no starch, but oily and albuminous
matter instead. Bran contains the husk, the
coats of the seed, and the envelope of the body
of the seed.

If a portion of the flour be formed into a
stiff paste, and then thoroughly washed, the
water will carry off a considerable part of the
dough, assuming at the same time a milky appearance,
and a tenacious solid will be left
behind, which is called the gluten. The milky
liquid, if allowed to stand, will deposit a sediment,
which is the starch. The liquid remaining
after the starch has settled at the bottom, is
colourless, but holds in solution dextrine, grape
sugar, and albumen. It is called the extractive.
These are the chief ingredients in flour,
and the albumen and gluten are what are
termed nitrogenised substances, having, chemically,
a close resemblance to the flesh of animals.