to him in the earliest periods of the world. Of these last, the Adansonia digitata, or calabash tree, is perhaps one of the most extraordinary. Indigenous to the land of the patriarchs, and still outrivalling the patriarchal age, this stupendous tree, compared with which our own giant oak, in bulk as well as in years, is but an infant, seems to require not less than a thousand years to give it full vigour and maturity. Extending its enormous arms over the dry and barren soil from which it shoots naturally, it affords shelter to whole nations of barbarians, and n its pleasant subacid fruit administers an ample supply to their hunger.

Let it not, however, be imagined that, by pointing out such frequent instances of resemblance between animal and vegetable life, I mean to degrade the rank of animal being from its proper level; for it will be one of the chief objects of our subsequent studies to develope and delineate its multiform and characteristic superiorities. I am only tracing at present the common principle of vitality to its first outlines: I am endeavouring to unfold to you, in its simplest and rudest operations, that grand, and wonderful, and comprehensive system, which, though under different modifications, unquestionably controlling both plants and animals, from the first moment it begins to act infuses energy into the lifeless clod, draws forth form and beauty, and individual being, from unshapen matter, and stamps with organization and propensities the common

dust we tread upon. And if, in this its lowest scale of operation,— if, under the influence of these its simplest laws, and the mere powers (so far as we are able to trace them) of contractility and irritability, it be capable of producing effects thus striking, thus incomprehensible, what may we not expect when the outline is filled up and the system rendered complete? What may we not expect when we behold, superadded to the powers of contractility and irritability, those of sensation and voluntary motion? What, more especially, when to these are still further added the ennobling faculties of a rational and intelligent soul,—the nice organs of articulation and speech, the eloquence of language, -the means of interchanging ideas, and of embodying, if I may so express myself, all the phænomena of the mind?

Such are the important subjects to which our subsequent studies are to be directed. In the meantime, from the remarks which have already been hazarded, we cannot, I think, but be struck with the two following sublime characters, which pre-eminently, indeed, distinguish all the works of nature: - a grand comprehensiveness of scheme, a simple but beautiful circle of action, by which every system is made to contribute to the well-being of every system, every part to the harmony and happiness of the whole; and a nice, and delicate, and ever-rising gradation from shapeless matter to form, from form to feeling, from feeling to intellect, from the clod

to the crystal, from the crystal to the plant, from the plant to the animal, from brutal life to man. Here, placed on the summit of this stupendous pyramid, lord of all around him, the only being through the whole range of the visible creation endowed with a power of contemplating and appreciating the magnificent scenery by which he is encompassed, and of adoring its Almighty Architect at once the head, the heart, and the tongue of the whole - well, indeed, may he exult and rejoice! But let him rejoice with modesty. For, in the midst of this proud exaltation, it is possible that he forms but one of the lowest links in "the golden everlasting chain" of intelligence; that he stands on the mere threshold of the world of perception; and that there exists at least as wide a disproportion between the sublimest characters that ever were born of women, our Bacons, Newtons, and Lockes, our Aristotles, Des Cartes, and Eulers, and the humblest ranks of a loftier world, as there is between these highly-gifted mortals and the most unknowing of the animal creation. Yet MIND, thanks to its beneficent bestower! is itself immortal, and knowledge is eternally progressive; and hence man, too, if he improve the talents entrusted to him, as it is his duty to do, may yet hope, unblamed, to ascend hereafter as high above the present sphere of these celestial intelligences, as they are at present placed above the sphere of man. But these are speculations in some degree too sublime for us: the

moment we launch into them, that moment we become lost, and find it necessary to return with suitable modesty to our proper province, an examination of the world around us; where, with all the aids of which we can avail ourselves, we shall still find difficulties enough to try the wisdom of the wisest, and the patience of the most persevering.

233

LECTURE X.

ON THE PRINCIPLE OF LIFE, IRRITABILITY,
AND MUSCULAR POWER.

E

We have distinguished organic from inorganic matter; and have characterised the former, among other differences, by its being actuated in every separate form by an internal principle, and possessed of parts mutually dependent and contributory to each other's functions. What then is this internal principle, -this wonderful and ever active power, which, in some sort or other, equally pervades animals and vegetables,which extends from man to brutes, from brutes to zoophytes, from zoophytes to fucuses and confervas, the lowest tribes of the vegetable kingdom, whose general laws and phænomena constituted the subject of our last study, this fleeting and evanescent energy, which, unseen by the eye, untracked by the understanding, is only known, like its great Author, by its effects; but which, like him too, wherever it winds its career, is perpetually diffusing around it life and health, and harmony and happiness?

I do not here enter into the consideration of a thinking or intelligent principle, or even a prin