1155. Why, if we break the stem of a hyacinth, do we see a glutinous fluid exude?

Because, by breaking the stem, we rupture the vessels of the plant, and cause the nutritive fluid to escape. The sap of the plant is analogous to the blood of man, and the vessels, to the arteries and veins of the animal body.1156. Why, if we split the petal of a tulip, do we see cells containing matter of various colours?

Because, by splitting the petal of the flower, we disclose the anatomy of its structure, and bring to view those cells, or organs, of the vegetable body, by which the different colouring matters are secreted.1157. Why, if we break a pea-shell across, do we discover a transparent membrane which may be removed from the green cells underneath?

Because we separate from the cellular, or fleshy part of the shell, the membrane, which forms the epidermis, and answers to the skin of the animal body.1158. Why, if we cut through a cabbage stump, do we find an outer coat of woody fibre, and an inner substance of cellular matter?

Because the woody fibre forms a kind of skeleton, which supports the internal stricture of the plant, and gives form and character to its organisation. The woody fibre of plants is analogous to the bony structure of animal bodies.1159. Why, if we cut across the stem of a plant do we see numerous tubes arranged in parallel lines?

Because we thereby bring to view the vessels formed by the membranes and fibres of the vegetable body, for the transmission of the fluids, by which the structure is sustained.

"It was planted in a good soil by great waters, that it might bring forth branches, and that it might bear fruit, that it might be a goodly vine."—Ezekiel xvii.

Skeleton leaves, and seed vessels of plants, form exceedingly interesting objects, and serve to illustrate the wonderful structure of plants. With patience and care, they may be produced by any person, and will afford an interesting occupation. The leaves should be gathered when they are in perfection—that is, when some of the earliest leaves begin to fall from the trees. Select perfect leaves, taking care that they are not broken, or injured by insects. Lay them in pans of rain water, and expose them to the air to undergo decomposition. Renew the water from time to time, taking care not to damage the leaves. They need not be examined more than once a week, and then only to see that the water is sufficient to cover them. Give them sufficient time for their soft parts to become decomposed, then take them out, and laying them on a white plate with a little water, wash away carefully, with a camel-hair pencil, the green matter that clings to the fibres. The chief requirement is patience on the part of the operator, to allow the leaves and seed vessels sufficient time to decompose. Some leaves will take a few weeks, and others a few months, but a large panful may be put to decompose at the same time, and there will always be some ready for the process of cleansing. When they are thoroughly cleaned, they should be bleached, by steeping for a short time in a weak solution of chloride of lime. They should then be dried, and either pressed flat, or arranged in bouquets for preservation under glass shades. The result will amply reward the perseverance of the operator.1160. Why are clayey soils unfavourable to vegetation?

Because the soil is too close and adhesive to allow of the free passage of air or water to the roots of the plants; it also obstructs the expansion of the fibres of the roots.1161. Why are sandy soils unfavourable to vegetation?

Because they consist of particles that have too little adhesion to each other; they do not retain sufficient moisture for the nourishment of the plants; and they allow too much solar heat to pass to the roots.1162. Why are chalk soils unfavourable to vegetation?

Because they do not absorb the solar rays, and are therefore cold to the roots of plants.1163. Why are mixed soils favourable to vegetation?

Because they contain the elements of nutrition essential to the development of the vegetables, and the plants absorb from them those constituents which are necessary to their growth.1164. Why do farmers sow different crops in rotation?

Because every plant takes something from the soil, and gives something back; but all kinds of plants do not absorb nor restore the elements in the same proportions. Therefore a succession of crops of one kind would soon impoverish the soil; but a succession of crops of different kinds will compensate the soil, in some degree, for the nourishment withdrawn.

"He watereth the hills from his chambers; the earth is satisfied with the fruit of thy works."—Psalm civ.

1165. Why do farmers manure their lands?

Because, as soils vary, and crops impoverish the soils, the farmer employs manure to restore fertility, and to adapt the soils to the wants of the plants he desires to cultivate.

It is remarkable that Nature herself points out to man the necessity for changing the succession of vegetable growths.

When plants have exhausted the soil upon which they grow, they will push their roots far in search of sustenance, and in time migrate to a new soil, while other plants will spring up and thrive upon the area vacated. When a forest in North America is destroyed by fire, the trees that grow afterwards are unlike those that the fire consumed, and evidently arise from seeds that have long lain buried in the earth, waiting the time when the ascendancy of the reigning order of plants should cease.1166. Why are grasses so widely diffused throughout nature?

Because they form the food of a very large portion of the animal kingdom. They have therefore been abundantly provided. No spot of earth is allowed to remain idle long. When the foot of man ceases to tread down the path, grass immediately begins to appear; and by its universality and the hardihood of its nature, it clothes the earth as with a carpet.

Many grasses, whose leaves are so dry and withered that the plants appear dead, revive and renew their existence in the spring by pushing forth new leaves from the bosom of the former ones.—Withering's Botany.

Grasses are Nature's care. With these she clothes the earth; with these she sustains its inhabitants. Cattle feed upon their leaves; birds upon their smaller seeds; men upon the larger; for, few readers need be told that the plants which produce our bread-corn, belong to this class. In those tribes which are more generally considered as grasses, their extraordinary means and powers of preservation and increase, their hardiness, their almost unconquerable disposition to spread, their faculties of reviviscence, coincide with the intention of nature concerning them. They thrive under a treatment by which other plants are destroyed. The more their leaves are consumed, the more their roots increase. The more they are trampled upon, the thicker they grow. Many of the seemingly dry and dead leaves of grasses revive, and renew their verdure in the spring. In lofty mountains, where the summer heats are not sufficient to ripen the seeds, grasses abound which are viviparous, and consequently able to propagate themselves without seed. It is an observation, likewise, which has often been made, that herbivorous animals attach themselves to the leaves of grasses; and, if at liberty in their pastures to range and choose, leave untouched the straws which support the flowers.—Paley.

"For the earth bringeth forth fruit of herself; first the blade, then the ear, after that the full ear in the corn."—Mark v.