« VorigeDoorgaan »
sess this adhesive, generative, quality, when applied to the bark of trees.
IV. Another instance of the compensatory system is in the autumnal crocus or meadow faffron, (cboleicum autumnaie). I have pitied this poor plant a thoufand times. Its blossom rises out of the ground in the most forlorn condition possible; without a sheath, a fence, a calyx, or even a leaf to protect it: and that, not in the spring, not to be visited by summer funs, but under all the difadvantage? of the declining year. When we come howeverto look more closely into the structure of this plant, we find that, instead of its being neglected, nature has gone out of her course to provide for its security, and to make up to it for all its desects. The seed-veflel, which in other plants is situated within the cup of the flower, or just beneath it, in this plant lies buried ten or twelve inches under ground within the bulbous root. The tube of the flower, which is seldom more than a few tenths of an inch long, in this plant extends down to the root. The styles always reach the seedveflel; but it is in this, by an elongation unknown to any other plant. All these singularities contribute to one end. "As this plant
blossoms blossoms late in the year, and, probably, would not have time to ripen its feeds before the access of winter which would destroy them, Providence has contrived its structure such, that this important office may be performed at a depth in the earth out of reach of the usual effects of frost*." That is to fay, in the autumn nothing is done above ground but the business of impregnation; which is an affair between the antheræ and the stigmata. The maturation of the impregnated seed, which, in other plants proceeds within a capsule, exposed together with the rest of the flower to the open air, is here carried on, and during the whole winter, within the heart, as we may fay, of the earth, that is, " out of the reach of the usual effects of frost." But then a new difficulty presented itself. Seeds, though persected, are known not to vegetate at this depth in the earth. Our seeds therefore, though so safely lodged, would, after all, be lost to the purpose for which all seeds are intended. Lest this should be the case, " a second admirable provision is made to raise them above the surface when they are persecuted, and to sow them at a proper distance;" viz. the germ grows up in the spring, upon a fruit-stalk, accompanied with leaves. The seeds now, in common with those of other plants, have the benefit of the summer, and are sown upon the surface. The order of vegetation externally is this. The plant produces its flowers in September; its leaves and fruits in the spring following.
V. I give the account of the dionaa muscipula, an extraordinary American plant, as some late authors have related it; but, .whether we be yet enough acquainted with the plant to bring every part of this account to the test of repeated and familiar observation, I am unable to fay. Its leaves are jointed, and furnished with two rows of strong prickles; their surfaces covered with a number of minute glands, which secrete a sweet liquor, that allures the approach of flies. When these parts are touched by the legs of flies, the two lobes of the leaf instantly spring up, the rows of prickles lock themselves fast together, and squeeze the unwary animal to death *." Here, Under a new model, we recognise the ancient
* Smellie's Phil, of Nat. Hist. vol. i. p. 5.
plan plan of nature; viz. the relation of parts and provisions to one another, to a common office, and to the utility of the organized body to which they belong. The attracting syrup, the rows of strong prickles, their position so as to interlock, the joints of the leaves; and, what is more than the rest, that singular irritability of their surfaces, by which they close at a touch; all bear a contributory part in producing an effect, connected either with the defence, or with the nutrition of the plant.
Hen we come to the elements, we take leave of our mechanics; because we come to those things, of the organization of which, if they be organized, we are confessedly ignorant. This ignorance is implied by their name. To fay the truth, our investigations are stopped long before we arrive at this point. But then it is for our comfort to find, that a knowledge of the constitution of the elements is not necessary for us. For instance, as Addison has well observed, "we know water sufficiently, when we know how to boil, how to freeze, how to evaporate, how to make it fresh, how to make it run or spout out, in what quantity and direction we please, without knowing what water is." The observation of this excellent writer has more propriety in it now, than it had at the time it was made: for the constitution, and the constituent parts, of water, appear in some measure to have been lately