may be cut from the parent trunk, and it will become an independent tree. This is done naturally by the banyan-tree, one of the most singular and beautiful of eastern products of vegetation. The branches incline downwards and fix in the soil, from whence a thick grove of young shoots springs up around.

We have already alluded to the wonderful power of assimilation possessed by vegetables, whereby, from the elements of the earth, the air, and the water, they produce such a wonderful variety of substances, all differing so much in their properties. and appearance. From wheat and other grains we have a substance called gluten, which is exactly si

milar to the substance which forms a principal part of the animal fibre. We have also in vegetables phosphate of lime,—an earth which enters largely into the composition of the bones of animals. Then there is starch, and sugar, and mucilage, formed in abundance by vegetables; and what is more surprising, from bland, and inodorous, and almost tasteless materials, we have pungent aromatic oils, gums, balsams, and every variety of odours. Even the metals, as iron and some others, are found entering into the composition of plants; and the bark of the bamboo contains a considerable quantity of flint. Potass and soda, which are so useful as entering into the composition of our soaps, are also vegetable products; and some of our most pleasing and grateful acids have a vegetable origin. Even virulent poisons, too, will be found to be produced in abundance by some plants, and many other substances, noxious to animal life in certain quantities, but medicinal in others.

There are species of vegetables, like animals, adapted to varieties of climate and temperature; although, from a careful provision of Nature, those vegetables and plants which are most essential to the maintenance of man will be found to bear a

variety of climate better than most others. This is the case with greens, carrots, potatoes, and many kinds of grain. Altitude has much the same effect as difference of latitude on the production of various plants; and thus we find in a high mountain, where at the summit it is perpetual winter, while as we gradually descend it becomes more genial, there is a beautiful succession of plants requiring different temperatures. Warm climates are much more favourable to vegetation than cold. In Spitzbergen the whole number of plants with conspicuous flowers, natives of the country, is found by botanists scarcely to exceed thirty species; while in the warmer regions of the West Indies, in Madagascar and the coast of Coromandel, Willdenow enumerates from four to five thousand different species of indigenous plants.

By cultivation, and the arts of agriculture, vegetables are greatly improved, and rendered more suitable to the uses of man; in some instances their natures are altogether changed. According to Buffon, our common wheat is an artificial production, improved to its present state by the assiduous cultivation of man. And it is most likely that rice, rye, barley, and oats, were originally but in

significant grasses, till improved by cultivation; for we nowhere meet with any of these grains vegetating in a state of nature. Thus, too, the apium graveolens, an acrid and poisonous plant, is converted by blanching into the agreeable and salutary salad, celery. The colewort, in its natural state a plant with very scanty leaves, has been reared into cabbages, cauliflowers, &c. Potatoes have no doubt undergone great improvements in quality since first made known as an esculent root. The engrafting of apple and other fruit trees has tended to diffuse valuable varieties; and even our garden-flowers assume deeper and more lovely tinges from the art and culture of the gardener.

This

Vegetables being organized substances, are liable, like animals, to various kinds of disease. proceeds from a vitiated state of their juices,— from a derangement of their organic structure, thereby causing an imperfect exercise of their functions, and from the attacks of parasitical plants, as fungi, &c. A particular state of the atmosphere, too, producing the common appearance of blight, is a frequent cause of disease. This blight is mentioned by ancient writers as frequently damaging the vineyards of Italy; and it prevails in our own

day among the hop-plantations of England, and in our most flourishing and luxuriant wheat-fields. It generally occurs about the end of July, in hot sunny weather, and after a shower. It seems to extend along the middle of the vineyard or hopground, and leaves a track of desolation in its course. Fields of wheat, too, are often blasted in a similar manner; sometimes only a part suffering, while at other times a whole field is destroyed..

A kind of minute fungus is often found attacking the leaves and stems of our grasses and grains, such as wheat, barley, and oats. It is in appearance a brownish-looking powder, hence the appellation of rust, given it by agriculturists. Upon close inspection it will be found to consist of thousands of minute globules, arranged in, groups be-. low the skin or covering of the plant. Sir Joseph Banks ascertained them to be a species of fungusthe minute seeds of which, floating about in the air, enter the pores of the leaf, especially if the plant is sickly; or they may exist in the soil or in the manure, and may be taken up by the absorbent vessels of the roots.

There is another kind of fungus called the red gum, which attacks the ear of the plant, and of course is much more destruc