euphorbia mauritanica; flower propagating flower from generation to generation.

But perhaps the plant most decisive upon this subject is the aërial epidendrum*, first, if I mistake not, described by that excellent Portuguese phytologist Loureiro, and denominated aërial from its very extraordinary properties. This is a native of Java, and the East Indies beyond the Ganges; and, in the latter region, it is no uncommon thing for the inhabitants to pluck it up, on account of the elegance of its leaves, the beauty of its flower, and the exquisite odour it diffuses, and to suspend it by a silken cord from the ceilings of their rooms; where, from year to year, it continues to put forth new leaves, new blossoms, and new fragrance, excited alone to fresh life and action by the stimulus of the surrounding atmosphere.

That stimulus is oxygene: ammonia is a good stimulus, but oxygene possesses far superior powers; and hence, without some portion of oxygene, few plants can ever be made to germinate. Hence, too, the use of cow-dung and other animal recrements, which consist of muriatic acid and ammonia: while in fat, oil, and other fluids, that contain little or no oxygene, and consist altogether, or nearly so, of hydrogene and carbone, seeds may be confined for ages without exhibiting any germination whatever. And hence, again, and the fact deserves to be extensively known, however torpid a seed may be, and destitute of all power to vegetate in any other substance, if steeped in a diluted solution of oxygenated muriatic acid, at a temperature of

* Epidendrum flos aëris.

about 46° or 48° of Fahrenheit, provided it still possess its principle of vitality, it will germinate in a few hours. And if, after this, it be planted, as it ought to be, in its appropriate soil, it will grow with as much speed and vigour as if it had evinced no torpitude whatever.

I have said that few plants can be made to germinate when the oxygene is small in quantity, and the hydrogene abundant: and I have made the limitation, because aquatic plants, and such as grow in marshes and other moist places, are remarkable not only for parting with a large quantity of oxygene gas, but also for absorbing hydrogene gas freely; and are hence peculiarly calculated for purifying the regions in which they flourish, and in some sort for correcting the mischief that flows from the decomposition of the dead vegetable and animal materials that is perpetually taking place in such situations, and loading the atmosphere with febrile and other miasms.

But the instances of resemblance between animal and vegetable physiology are innumerable. Some plants, like a few of our birds, more of our insects, and almost all our forest beasts, appear to sleep through the day, and to awake and become active at night; while the greater number, like the greater number of animals, resign themselves to sleep at sunset, and awake re-invigorated with the dawn. Like animals they all feel the living power excited by small degrees of electricity, but destroyed by severe shocks; and like animals, too, they differ in a very extraordinary degree in the duration of many of their species. Some tribes of boletus unfold themselves in a few hours, like the

ephemera and hemerobious tribes (May-fly and Spring-fly), and as speedily decay. Several of the fungi live only a few days; others weeks or months. Annual plants, like the greater part of our insects, live three, four, or even eight months. Biennial plants, like the longer-lived insects, and most of our shell-fishes, continue alive sixteen, eighteen, or even twenty-four months. Many of the herbaceous plants continue only a few years, but more for a longer period, and imitate all the variety to be met with in the greater number of birds, quadrupeds, and fishes; while shrubs and trees are, for the most part, coequal with the age of man, and a few of them equal that allotted 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 tribes of barbarians, and in 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 organisation 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 mean time, from the remarks which have already been hazarded, we cannot, I think, but be struck with the two following sublime characteristics, which preeminently, 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 intrusted 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