created on the system of having a living p them, capable of producing these various principle is not their material organization. when they die, like the animal body on a sud sists in all its completeness at that moment, no longer perform any of the functions of its . something different from heat, light, and elec can act upon its frame while it abides there, be of these aerial fluids can supply its place or after its departure. It is distinguished from from all inorganic matter by its peculiar powe possesses in both plants and animals, of count laws of chymical affinity while it is in the org although these begin to operate irresistibly as so retired.* Vegetable life resembles nothing known in · animal life, and with this it has a striking analog of their functional operations we have noticed to and these, in both, require the presence and co-op their living principle, and cease in both when the drawn. Its presence and activity first appear in the ger of the seed or bud, as they do in the animal egg v warmth of incubation. In plants germination have a specific and regular term of germination in e ticular species. But though cold represses it, ye pression only causes it in the regions of frost an spring up, as soon as the brief season of heat oce * Humboldt remarked this law, by which no vegetable sut. faction or decomposition in any part until its living principle from it: then a leaf changes, and a flower decays, and a bran but not till life has left that part. + Adamson has given this table of the periods in which th seeds germinate after being sown:- A By steeping the seed in the chlorine gas, the process was cress-seed then began its germination in 32 hours. that they would not grow in heterogeneous hydrogen Enc. 196. created on the system of having a living principle within them, capable of producing these various results. This principle is not their material organization, because this, when they die, like the animal body on a sudden death, subsists in all its completeness at that moment, and yet it can no longer perform any of the functions of its life. It is also something different from heat, light, and electricity, which can act upon its frame while it abides there, because neither of these aerial fluids can supply its place or do its offices after its departure. It is distinguished from its own and from all inorganic matter by its peculiar power, which life possesses in both plants and animals, of counteracting the laws of chymical affinity while it is in the organic frame, although these begin to operate irresistibly as soon as it has retired.* Vegetable life resembles nothing known in nature but animal life, and with this it has a striking analogy. Many of their functional operations we have noticed to be alike; and these, in both, require the presence and co-operation of their living principle, and cease in both when that is withdrawn. Its presence and activity first appear in the germination of the seed or bud, as they do in the animal egg under the warmth of incubation. In plants germination seems to have a specific and regular term of germination in each particular species. But though cold represses it, yet this repression only causes it in the regions of frost and snow to spring up, as soon as the brief season of heat occurs, with * Humboldt remarked this law, by which no vegetable suffers putrefaction or decomposition in any part until its living principle has retired from it then a leaf changes, and a flower decays, and a branch withers, but not till life has left that part. Adamson has given this table of the periods in which the following seeds germinate after being sown:- .... 9 days. .... Wheat; millet 1 day. Purslain. 10 Lettuce; aniseed Melon; cucumber; cress 5 Parsley 40 or 50 Almond; chestnut; peach 1 year. By steeping the seed in the chlorine gas, the process was hastened: cress-seed then began its germination in 32 hours. Achard found that they would not grow in heterogeneous hydrogen gas.--Loud. Enc. 196. a rapidity which the temperate climates do not experience.* It can lie dormant without expiring in some species, when it seemed to have forsaken them.t This living principle has the singular property of remaining dormant and inert for years or ages, without therefore ceasing to exist. We all know that seeds may be kept a long while unsown, and yet grow whenever planted in a suited soil. This, again, is like animals who have been found enclosed in trees, and yet have revived. When plants are buried in the ground to a greater depth than is natural to them for their proper growth, they do not vegetate; but they do not therefore die: they retain their power of vege tation to an unlimited period; and when, by any accident, brought so near the surface as to suit their evolution, they begin immediately to grow. Ground that has not been disturbed for some hundred years, on being ploughed or turned up for any considerable depth, has frequently surprised the cultivator by the appearance of plants which he never sowed, and often which were then unknown to the country. This has arisen from ancient seeds becoming deeply covered, and there remaining inert, but yet retaining their principle of life. This principle has been ascertained to be capable of existing in this latent state for above two thousand years unextinguished, and springing again into * A Lapland and Siberian yew exhibits remarkably rapid vegetation, beginning and fruiting in a single month; thus July 1.-Snow gone. 9.-Fields quite green. Aug. 2.-Fruit ripe. 18.-Snow. And from that time snow and ice to the 23d of June, when they begin to melt. † Thus mosses "Are extremely tenacious of life; and after being long dried, easily recover their health and vigour by moisture. Their beautiful structure cannot be too much admired."-Sir J. Smith, Intr. 493. "If the ground in old established botanic gardens be dug much deeper than ordinary, it frequently happens that species which have been long lost are recovered, from their seeds being latent in the soil."Ib. 94. A field that was thus ploughed up near Dunkeld, after a period of forty years' rest, yielded a considerable blade of black oats without sowing. It could have been only from the plough's bringing up to the surface seeds that had been formerly too deeply lodged for germination."Loud. Encyc. Gard. 194. active vegetation as soon as planted in a congenial soil.* It even remains unimpaired in blighted corn, and will grow from that as vigorously as from the perfect seed.+ But yet, although thus abiding in vitality in its dormant state for an indefinite length of time, such is its delicacy of existence when once roused into its living action, that it perishes for ever if it be prevented from continuing its growth.‡ This living principle can subsist in all its reproductive power in fruit-trees from one to two centuries, and in others for many more. Some of the poisons affect the activity of this principle, though they do not destroy it.¶ But although we can observe these effects, we do not know what vegetable life really is. We can discern it to be something distinct and different from all the known material agencies of nature. These can excite and affect and assist the agency, but cannot without it do what it does, nor be what it is. We are therefore authorized to deem it a peculiar sui generis principle, as distinct in plants from their material laws and substance as life and instinct are in animals. It is affectible or can be influenced by light, in its stem, leaf, and flower. It turns to this the upper surface of its leaves, and if they be forcibly turned from it they will At the Royal Institution in 1830, Mr. Houlton produced a bulbous root, which had been discovered in the hand of an Egyptian muinmy, where it had remained above two thousand years. On exposure to the atmosphere it germinated, and when planted in earth it grew with great rapidity. Jour. Roy. Instit. No. 1. † Sir Joseph Banks, in 1805, sowed eighty grains of the most blighted wheat in pots, in a hot-house, and had seventy-two healthful plants. "Those who convey seeds from distant countries should be instructed to keep them dry; for if they receive any damp, sufficient to cause an attempt at vegetation, they then necessarily die, because the process, as they are situated, cannot go on."-Smith's Introd. 99. An apricot-tree one hundred and twenty years old, was bearing fruit sufficient for any family.-Life of L. Kames, vol. ii. p. 73. Pear-trees planted in the time of King William were, by gradual paring away the old wood and bark, covering the garden walls with new branches and fine fruit in 1807.-Smith, Intr. p. 29. A yew-tree was in existence at Peronne, in Picardy, in 1790, which was mentioned in the original charter for building the church in 634.— Journ. of Science, No. 40, p. 412. The most vital parts of the stem of a tree are thought to be the innermost layers of the bark, and the outermost layers of the wood.-Quart. Journ. Agric. Thus sensitive plants lose their power of contracting, if laurel water, opium, or nux vomica be applied. So they contract from camphor, and do not dilate again.-Quart. Journ. Science, vol. ix. p. 203. |