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STRUCTURE AND PHYSIOLOGY OF VEGETABLES AND THEIR
CULTIVATION AND USES.
I. WERE all the known objects diffused over the surface of the earth, submitted to the examination of a certain number of individuals accustomed to nice and patient investigation, but altogether ignorant of any arrangement hitherto proposed, there can be but little doubt that the same classification would be adopted by all; and that the objects would be divided into three grand assemblages; namely, minerals, plants, and animals, such being in fact, for the purposes of description, at least, the most convenient distribution that could be adopted. Thus, there is no difficulty in distinguishing this mineral body from that plant, or this plant from a horse, an elephant, or any other quadruped. Yet, when we come to examine the confines of these several kingdoms of Nature, we find that so nice are the shades and gradations, and so gradual the transitions from one class of bodies to the other, that objects frequently present themselves, to which it would be difficult to assign their proper compartment.
However striking, therefore, the distinctions be. tween animal and vegetable life, in their more perfect and elaborate forms, as we approach the contiguous extremities of the two kingdoms, we find these distinctions fading away so gradually, Shade, unperceived, so softening into shade,
and the mutual advances so close and intimate, that it becomes a task of no common difficulty to draw a line of distinction between them, and determine to which of them an individual may belong.
M. de Mirbel, in his treatise “ On the Anatomy and Physiology of Plants," has endeavoured to lay down a distinction between animals and vegetables in the following terms, and it is a distinction which seems to be approved of by Sir Edward Smith “Plants alone have a power of drawing nourishment from inorganic matter, mere earths, salts, or air — substances incapable of nourishing animals, which only feed on what is or has been organised matter, either of a vegetable or animal nature. So that it should seem to be the office of vegetable life alone to transform dead matter into organised living bodies.”
Dr. Good objects to this distinction between vegetable life and animal life, and observes, that in laying down a distinctive character for animals and plants, we are compelled to derive it from the more perfect of each kind, leaving the extreme cases to be determined by the chemical components elucidated on their decomposition. Under this broad view of the subject he proceeds to observe, that while they agree in an origin by generation, a growth by nutrition, and a termination by death; in an organised structure, and an internal living principle, they differ in the powers with which the living principle is endowed, and the effects it is capable of exerting. In the plant it is limited, so far as are capable of tracing it, to the properties of irritability, contractility, and simple instincts ; in the animal it superadds to these
properties those of muscularity, sensation, and voluntary motion.*
II. The structure of vegetables is truly wonderful, and demands our admiring attention. How excellently adapted are the roots for taking hold of their parent earth, as well as for drawing nourishment for the support of the plant, and imbibing moisture from the neighbouring soil! How commodiously are the various tubes and fibres composing the trunk or stalk arranged for the motion of the sap upwards, to all the extremities of the leaves and branches ! How nicely are the leaves formed for the important services they are made to yield in the economy of vegetation! What an excellent clothing does the bark afford, not only for protecting the stem and branches from external injury, but from the hurtful extremes of heat and cold ! What evident marks of wisdom and design do the flowers evince in their beautiful and delicate construction; how nicely are they formed for the protection and nourishment of the first and tender rudiments of the fruit, and when it has attained more firmness and solidity, how readily do they relinquish their charge, and drop off in decay, when no longer necessary! How wonderfully does the fruit, in some classes, envelop and protect the seed till it has arrived at maturity; and, lastly, what a passing strange piece of organised mechanism is the seed itself, and, being necessary for the reproduction of its species, what a remarkable provision is made for its preservation and succession! What but the wisdom of a Deity could have devised that those seeds which are most exposed to the ravages of the inhabitants of the forest should not only be doubly, but some of them trebly * “ Book of Nature," vol. i. p. 171.
enclosed ;* that those most in request as articles of food should be so hardy and so abundantly prolificit and that seeds in general, which are the sport of so many casualties, and exposed to injury from such a variety of accidents, should be possessed of a principle of lasting vitality, which makes it indeed no easy matter to deprive them of their fructifying power ! Plants are also multiplied and propagated in a variety of ways, which strengthen the provision made for their succession.
Nor is the finger of Providence less visible in the means for diffusing or spreading abroad vegetables, than in the provision made for keeping up their succession. The earth may be said to be full of the goodness of the Lord; but how comes it to pass, that in parts untrodden by man, and on the tops of ruinous buildings, so many varied specimens of the vegetable creation are to be found ? Is it not from the manner in which nature's great husbandman scatters His seeds about ? While the seeds of some plants are made sufficiently heavy to fall down and take up their abode near the place of their nativity ; and others after having been swallowed up by quadrupeds, are deposited in the neighbouring soil ; some are carried by the fowls of the air to places more remote, or, being furnished with a soft plumage, are borne on the winds of heaven to the situations allotted for them. To prevent some from pitching too near, they are wrapped up in elastic cases, which, bursting when fully ripe, the prisoners fly abroad in all direc
* As in the walnut, we have first a thick pulpy covering, then a hard shell ; within is the seed, enclosed in a double membrane.
† Wheat is not only a most prolific plant, but comes to maturity in hot and cold, as well as in temperate, climates.
tions; while, to prevent others from straying too far, they are furnished with a kind of grappling hooks, that arrest them in their flight, and attach them to the spot most congenial to their growth. These are some of the doings of the Lord, and are wondrous in our eyes !
In the construction of plants we observe a considerable difference in the consistence of the three classes. Compared with the shrubby race, how hard, firm, and tenacious is the trunk of the majestic oak; and, compared with the herbaceous tribe, how woody, tough, and elastic is the hawthorn twig! But for this, how could the mighty monarch of the wood have been able to withstand the fury of the tempest? While the more humble and lowly shrubs stand not in need of such firmness of texture, their pliability and elastic toughness, together with the prickly coat of mail by which they are enveloped, render them less susceptible of injury in their exposed situation.
Softness, united with a still greater degree of flexibility, are the distinguishing characteristics of the herbaceous order; and how wisely has this been ordered for the various purposes for which they were created ! With the firmness of trees, to what a prickly stubble must Nature's soft and downy carpet have given way! With the tenacity of shrubs, how would it have answered as food for our cattle?
There are, besides, a number of other properties and peculiarities in the vegetable kingdom, in which the wonderful working of the Divine Creator is displayed. How strange, for instance, that if a seed is sown in a reverse position, the young root turns of itself downwards, while the stem refuses to sink deeper in the soil, and bends itself round to shoot up through the surface of the earth! How surprising,