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Show [ 38 With nice [election modefi RUBIA blends Her vennil dyes, and o'er the cauldron bends; 'Vann 1nid the rifing fl:eam the Beauty glows, As bluihes in a tnifi the dewy rofe. With chemic art Jour favour' d youths aloof 375 Stain the white fleece, or firetch the tinted woof; 3 8o Ruhia. 1. 37 5· Madrler. Four males and one female. This plant_ is culti~ated in very large quanttties for dying red. If mixed with the food of young prgs or chiCkens, it colours their bones red. If they are fed alternate fortnights, with a mixture of madder, and with their ufual food alone, their bones will confifl: of concentric circles of white and red. l3elchier. Phil. Tranf. 1736. Ani mals fed with madder for the pur-ofe of thefe experiments were found upon diffeCl:ion to have thinner gall. Comment. ~e rebus. Lipfi::e. This circumfl:ance is worth farther attention. The colouring materials of vegetables, like thofc which ferve the purpofe of tanning, varnifhing, and the various medical purpofes, do not feem effential t0 the life of the plant; but feem given it as a defence againfl: the depredations of infects or other animals, to whom thefe materials are naufeous or deleterious. The colours of infects and many fmal\er animals contribute to conceal them from the larger ones which prey upon them. Caterpillars which feed on leaves are generally green; and earth-worms the colour of the earth which they inhabit; butterflies which frequent flowers are coloured like them ; fmall birds which frequent hedges have greenifh backs like the leaves, and light coloured bellies like the fky, and are hence lefs vifible to the hawk, who paffes under them or ov r them. Thofe birds which are much amongfl: flowers, as the goldfinch, (Fringilla Carduelis) are furnifhed with vivid colours. The lark, partridge, hare, are the colour of dry vegetables, or e:nth on which they rcfl:. And frogs vary their colour with the mud of the Hreams which they frequent; and thofe which live on trees are green. Fifh, which are generally fufpended in water, and [wallows, which are generaJiy fufpended in air, ha\'C th ir backs the colour of the diftant ground , aNd th eir bellies of the fky. In the colder climates many of thcfe become white during the exiflence of the fnows. Hence there is apparent llefign in the colours of animals, whil!1 thofe of vegetables feem confequent to the oth r properties of the materials which polfefs them. [ 39 J O'er Age's cheek the warn1th of youth diffufe, Or deck the pale-eyed nymph in rofeate hues. So when rviEDEA to exulting Greece Fro1n plunder' d CoLciirs bore the golden fleece; On the loud .fhore a n1agic pile ibe rais,d, The cauldron bubbled, and the faggots blaz' d; Pleafed on the boiling wave old JEsoN fwin1s, And feels new vigour firetch his fwelling limbs; Through his thrill'd nerves forgotten ardors dart, And warmer eddies circle round his heart ; With fofter fires his kindling eye-balls glow, And darker trc!fes wanton round his brow. Pleafed on the hailing wave. 1. 387. The !lory of JEfon becoming young, from the medicated bath of Medea, feems to have been intended to teach the efficacy of warm bathing in retarding the progrefs of old age. The words relaxation and bracing, which are generally thought expreffive of the effeCl:s of warm and cold bathing, are mechanical terms, properly applied to drums or firings; but are only metaphors when applied to the effects of cold or warm bathing on animal bodies. The immediate caufe of old age feems to refide in the inirritability of the finer veffels or parts of our fyfl:em; hence thefe ceafe to aCl:, and collapfe, or become horny or bony. The warm bath is peculiarly adapted to prevent thefe circumfiances by its increafing our irritability, and by moifl:ening and foftening the fkin, and the extremities of the finer veffels, which termmate in it. To thofe who are pail: the meridian of life, and have dry fkins, :md begin to be emaciated, the warm bath, for half an hour twice a week, I believe to be eminently ferviceable in retarding the advances of age. |