their ancestors, be whirled into the sea.
These regular periodic processes of the life-
circle of this wee rose struck the simple
imaginations of the men of old with
superstitious awe, and they invested it with
miraculous virtues.

There are also seeds which contain enough
of humidity in themselves for germination.
Potatoes require only to be planted to sprout,
and hyacinth and tulip bulbs grow everywhere,
when set in a little moss. Moreover,
there is another, although extremely rare
instance of this fact. The mango-trees, which
grow in very damp and marshy soil upon
the tropical sea-shores, bear their seeds at the
tips of their branches. These seeds do not
fall when ripe, but sprout out their radicles
or roots three or four feet long from the
parent tree, until they reach the ground.
They then plant themselves in the soil, and
produce leaves, flowers, and fruit, and each
plant multiplying in turn in this way, the
progeny of a single tree will sometimes
spread themselves, until in time they are
found covering an area of more than sixty
miles.

Not the least important element in
germination is the temperature to which the
plant is subjected. Of course, the amount
of heat requisite varies according to the
plant and the climate, but germination cannot
take place at zero centigrade, and rarely
does so under three or four degrees above
zero. In the hot countries, plants cannot
germinate under seven or eight degrees, the
usual temperature being eighteen or twenty;
but the temperature of germination rarely
goes more than forty degrees above zero.
The palm-trees sprout at a very high
temperature, but if it were much above forty
degrees, the seed would be spoilt. Corn,
kept in granaries through which pass
continual currents of hot air, is never injured
by germination.

Oxygenised air plays perhaps the most
important part in the sprouting of the little
heart. If a seed is placed at the bottom of
unoxygenised air, or in azotic gas, it will not
sprout; and if the soil is too compact for
the free admission of air, the young plant
dies. There is twenty-one per cent, of
oxygen in pure air, and if, after allowing a
grain to germinate tor a certain time under
a bell, the air is analysed, it will be found to
have lost six per cent. of oxygen, and to have
gained a large proportion of carbonic acid
gas. M. Bousingault tried the experiment
of weighing a dry farinaceous seed, and after
letting it sprout for a short time, drying it to
the same degree as before, and reweighing
it, and he found that it had lost a considerable
amount of weight by the evaporation of
oxygen, hydrogen, and carbonic acid gas. It
had not lost any azote, because azote was
necessary for its growth, but it had lost its
fecula and oily matter. When corn germinates,
the fecula softens, and becoming
milky, passes into the embryo. Theodore
Saussure made experiments upon fecula, and
found, that if when wet it is placed in
contact with the air, it absorbs oxygen, forming
a sugary mass, and exhaling carbonic acid
gas. This phenomenon is produced in
making malt from barley, and brandy out of
grain. Darkness is favourable to this
transformation, as well as the germination of
plants, because there is a great exhalation
of heat and carbonic acid gas in the process.
It is entirely unknown what becomes of the
gluten and oily substances in plants like the
maize.

As the seed germinates, the perisperme
and cotyledons gradually change their
appearance, becoming absorbed by the young
plant. The prolongation of the little root is
always the first sign of growth. And from
their first moment of existence, the roots
grow downwards and the stalks upwards.
If the seed sown is that of a monocotyledon
or one-lobed plant, like the wheat and the
palms, the root immediately spreads out in
all directions, and the seed-lobe appears
above the soil, wearing the appearance of a
thin green leaf, and forming a cylindrical
tube around the stem. But, if the seed is
that of a dicotyledon or two-lobed plant, like
the oak and the bean, the root shoots down
into the earth perpendicularly, and the seed-
lobes either remain underground and perish,
or appear above, forming the two first leaves.

The point of junction between the root and
the stem is commonly called the collar, but
Lamarck strikingly called it the vital point,
because a plant may be cut above it, or cut
beneath it, without being killed, whilst
cutting the vital point instantly deprives the
plant of life.

Such is the tenacity of a sprouting plant
to the vertical position, that if obstacles,
such as stones, are placed in the way either
of the root or of the stalk, they climb over them
and then take their natural direction. And
if a seed is planted upside downwards, the
root, after growing a short time upwards,
bends round gradually straight into the
earth; and the stem, after sprouting for a
while downwards, curves gently upwards
until it has freed itself entirely from the
soil.

It has been alleged that the stalk of a
plant is attracted towards the light, because
plants kept in a room always bend in the
direction of the window. But Duhamel
tried the experiment of placing a seed in a
dark tube, closed at the top, and only
admitting light at the bottom by means of a
mirror, and the stem was not attracted
downwards, showing that light is not the
first or principal agent of attraction.

It has been likewise said, that roots are
attracted towards humidity and the soil, and
fly from the light; but the experiments,
which have been made upon the subject of
humidity, have not as yet been deemed decisive.