to give up the honour and benefit of an important improvement in the arts or in science, rather than run the gantlet to substantiate his claims as the original inventor.,

It is with pleasure and profit, therefore, that we study a French author; and Dr. Dutrochet is conspicuous for simplicity and perspicuity, as well as for his honest and considerate attention to the claims of those who have preceded him in his particular studies. Never was there any thing more beautifully clear and satisfactory than his work entitled Anatomical and Physiological Researches-there is nothing equal to it extant. The Genevan philosopher, M. de Candolle, is likewise entitled to our gratitude, for he has added many new and useful hints. It has been the peculiar happiness of these two distinguished men, to know that they have infused more spirit into the study, and have created a greater eagerness for pursuits of this kind, than any other previous writers on vegetable physiology. Thousands of minds have been set to work-and in the right way, too-they have not only been taught to think for themselves, but have been taught how to set about thinking.

Vegetable physiology, as treated by these gentlemen, is one of the most fascinating and satisfactory studies in the world; and happy must that man account himself, who has leisure and abilities to walk out in the fields and orchards, and look at the wonders which the learning of these philosophers has laid open to him. He who makes this branch of science a study, feels himself at once elevated far above ordinary men. He is entrusted with the key of knowledge, and he can at any mo.. ment unlock the door and walk in a world of delights; innocent pleasures of which the ignorant can form no conception.

It is gratifying, likewise, to pursue the same experiments, and with the same results, that were so clearly laid down by these able and ingenious men; but it is still more gratifying to know that our investigations have led to some discoveries that may, ultimately, add new light to this branch of science.

The closest observation, and the clearest view of the subject, prove to us that there are two indisputable points of resemblance between a plant and an animal-vitality and instinct. These two elementary principles are imparted, continued, and extinguished, in the same manner, whether infused in a moving or fixed body. In many other particulars, although a similarity in the physical structure and capacities can be traced, yet the organic material is so very different that there is great danger in being deceived. But in the two grand leading pointsvitality and instinct-the same laws govern both plants and animals; vicissitudes of climate, light, shade, moisture, dryness, nourishment, care, neglect, produce the same effect on a tree as on a man. It is partly to ascertain how the internal organs of

each are disposed, and to trace a connection between them, that these minute investigations have been made. What a simplicity there is in all the works of nature, that, with only a variation of the same powers-life, instinct, and matter-build up every thing that lives, and moves, and has a being!

Plants have the instinctive power of motion, and are impelled to it by external as well as internal influences. They have movements peculiar to themselves, either in the search of food, or to protect themselves from injury. This movement is effected by elongating the rootlets, and by folding up the leaves. Such processes, for ever going on, could only result from an irritation or excitement in the system similar to that which takes place in the animal economy. The bird, the bee, and the new-born child, have no more reason to guide them, when they go to the exac tspot for nourishment, than the spongelets of a tree have, which drink in by a similar process-suction-the fluid nutriment that the rootlets and slender filaments place within their reach. They are the arms or feelers, on the surface of which the spongelets are placed; and being placed on the surfaces of all the ramifications of these extremities, they are thus brought into immediate contact with the aliment suited to them.

We are very willing to use the term "nervimotion,” as introduced by Dr. Dutrochet, but it appears to us that irritability is quite as suitable as the one proposed. By irritability in the animal system we do not imply any mental perception of sensation, but simply a physical capacity to react on the application of pressure or deleterious stimulus. If a fly and a chicken be suddenly deprived of their head-which part, in the higher order of animal life, is the seat of volition-they still remain susceptible of the same movements, for a certain length of time, to which they were subject when the will could control them. The leg of the spider called long-legs will sometimes keep in motion, while lying flat, for upwards of a quarter of an hour. It imitates the motion of walking exactly as if it was still attached to the body of the spider, and yet in no insect or animal is the ligament and cuticle which connects it with the body so frail and delicate-almost a touch will separate the whole leg, having three joints, from the body.

In consequence of the reproductive principle with which plants are so strongly endowed, and of the remoteness of the extremities from the main radiating point, they are allowed a corresponding quantity of the vital principle. They possess it in greater proportion, and it is of longer continuance in the system, than that which is allowed to animals. There is, likewise, a slower development of this vital energy, which enables a plant the longer to resist the changes of climate, and of those

casualties to which they are the more subject in consequence of being deprived of the powers of speech and locomotion. The reproductive capacity, which plants possess in so remarkable a degree, eminently proves that they have this superabundant quantity of the vital principle.

Each articulation or joint of a plant has the special power assigned to it, not only to receive from the roots its own share of the crude sap as it rises, but of retaining and apportioning this sap to its own use, so as to sustain the particular twig that emanates from this articulation. Of course, when the terminal shoot is separated from the joint there is a reservoir of this cambium or elaborated juice at the base, which is sufficient to sustain the slip until it can strike out roots and support itself.

There is an important fact corroborative of this, which is this-the extremities of the tallest trees exhibit the first appearance of life when excited by the sun's rays in the spring; they show as much animation and vigour after being exposed to the cold of a Siberian winter, as if the general circulation had never been checked. Whereas tortoises, and other animals which lie torpid during the winter, are obliged to draw their limbs within the shell, or curl up their bodies in such a manner as to bring the extremities as closely as possible to vital heat. Plants, therefore, have a power connected with that of divisibility, by which heat is generated at the articulated sections, and this heat is excited even before the frost is out of the ground in the spring.

Although the organic structure of plants varies so much in different species, yet the same phenomena of vitality, instinct, and irritability, exist in all. The circulation of sap is so rapid in the grape vine, owing to the peculiarity of the interstitial medium, that, when wounded, the exhaustion from the copious discharge often endangers the life of the plant. The same effect is produced in seasons of great drought: the grape vine suffers for the want of a constant supply of fluid nutriment; if it be withheld the plant slowly loses its energy, the leaves hang loosely and without motion, and the unripe flaccid berries wither on the vines. Here an analogy can be traced between the animal and plant; but our object is chiefly to speak of vegetation, and not to draw comparisons.

The electric fluid will sometimes prostrate the energies of the grape vine. We have seen the leaves of a whole vineyard hang lifeless after a warm, gentle, July shower, during the hottest period of the day. Many of the vines never recovered from this syncope, if so it may be called. A warm shower in mid-day will sometimes produce the like effect on the sensitive plant, but it always revives after the shower is over.

Every thing that has life is more or less affected by the elec

tric fluid; that the sensitive plant shows its presence so instantaneously, is owing to the peculiarity of the ligament which connects the articulations and the cellular tissues. But the same revulsion or collapse takes place in all plants, only in a greater or less degree according to the activity of the vital principle. If we wound the bark of a tree, no external motion is visible; this arises from the rigidity of its parts, yet we feel assured that some commotion takes place internally at the very instant that the injury occurs. The work of repair goes on immediately; for, no sooner is the bark bruised than there is a rush of secretive matter to the spot, which covers the wound from the air, and in a short time the broken bark is renewed, having acquired additional strength by the healing process.

The external motion of some plants, and the motion that we feel assured is going on within others, may as well be called irritability as nervimotion. No one refers to mental action for the production of that convulsive movement of the spider's leg, nor of the hen when the head has been chopped off. These movements are the remains of the same principle which is common to plants and animals-vitality. This power, life, gradually disappears from the parts when they are separated from the head, but neither sensation nor consciousness have any share in producing these irregular movements; they are altogether involuntary. It is a fact worthy of observation, that these convulsive movements will be more violent in a hen that has been chased about for some time before her head was cut off, than if she had been taken quietly from the roost.

We perceive, therefore, that on any emergency the vital principle can be accumulated, and that it will remain in the system for some time after the controlling power, the will, has been separated from it. The body of the hen flounders and writhes about without any effort of will or design, just as a paper kite is dashed about by the winds when the string has been cut from the hand which controlled its motions.

If matter, undergoing fermentation, be placed under ground within the reach of the spongelets of an exhausted tree, its vigour will be restored. It is the gaseous particles which infuse new life, and why may we not expect a similar result from an introduction of gases into the veins when the system is in a state of collapse or exhaustion? Why not hope that it may renew life in a body that is debilitated by typhus, or sinking with a protracted disease. It is reasonable to suppose that when a fever is subdued, or has worn itself out, the introduction of certain vivifying gases, through a fluid medium, would at once give a new tone to the system, and prevent it from sinking.

Thoughts like the above present themselves to the mind while

studying the beautiful science of vegetable physiology. It is in vain for the closet philosopher to insist that no conclusion can be drawn from analogies such as these, or that no analogies exist. Our knowledge will eventually amount to this-that gases have been selected, by the wisdom of the Almighty, as the propelling power which is to circulate all elementary matter. When bodies are to be formed, or when injuries are to be repaired, the process is effected through the medium of a fluid. All equable and slow depositions of matter have been transferred to their resting place by the instrumentality of gases aided by a fluid menstruum. But when a rupture or a dismemberment, or any convulsion of nature, is to take place, gases are the sole agents; they then want no fluid medium-they are sufficient of themselves to produce all the pains incident to the human body, and all the violent phenomena which occur on earth. They are as necessary to the existence of a plant as to an animal; and it is only when there is an excess, or too small a portion of them, that organized systems perish.

Nerves seem only necessary to a system where sensation is to be conveyed, and sensation, or a consciousness of it, appears only to belong to animal life. Pliancy and contractibility are all that the organs of a plant possess, and all that vegetation requires, if we except the power of absorption; and yet that power, on reflection, is a mere contractile force. But, in which ever way we view the subject, we still find that gases are the propelling power.

The vitality of plants and of the inferior order of animals, particularly those which have the power of reproducing a limb, or an outer case or skin, continues long after sensation has ceased-for we must insist on calling that violent action which the headless body of a chicken exhibits, the effect of the vital principle. It is of precisely the same nature as it was when it pervaded the whole system, during the time when the animal was completely imbued with it, and when the will could control the movements of each organ.

It may be urged that galvanism can produce similar movements; but, in the case of the headless chicken, the agency of that fluid is not perceptible, although we grant that the time is fast approaching when the propelling power of the galvanic and electric fluids will be identified with that which animates or renders active the principle of life itself. Of this we are certain, that electricity has a powerful effect on vegetationnot only blasting and shattering the largest trees, but rupturing the sap vessels-thus producing congestion and death. But still, even in this, the propelling power, that which transports the electric fluid, is gas.

Although it is needless to enquire into the nature of that